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Structure at 1.0 A resolution of a high-potential iron-sulfur protein involved in the aerobic respiratory chain of Rhodothermus marinus.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The aerobic respiratory chain of the thermohalophilic bacterium Rhodothermus marinus, a nonphotosynthetic organism from the Bacteroidetes/Chlorobi group, contains a high-potential iron-sulfur protein (HiPIP) that transfers electrons from a bc (1) analog complex to a caa (3) oxygen reductase. Here, we describe the crystal structure of the reduced form of R. marinus HiPIP, solved by the single-wavelength anomalous diffraction method, based on the anomalous scattering of the iron atoms from the [4Fe-4S](3+/2+) cluster and refined to 1.0 A resolution. This is the first structure of a HiPIP isolated from a nonphotosynthetic...
Source: Journal of Biological Inorganic Chemistry : JBIC - November 18, 2009 Category: Chemistry Authors: Stelter M, Melo AM, Hreggvidsson GO, Hjorleifsdottir S, Saraiva LM, Teixeira M, Archer M Tags: J Biol Inorg Chem Source Type: journals

The manganese/iron-carboxylate proteins: what is what, where are they, and what can the sequences tell us?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The manganese/iron-carboxylate proteins make up a recently discovered group of proteins that contain a heterodinuclear Mn/Fe redox cofactor. The chemical potential of the heterodinuclear metal site is just starting to be characterized, but available data suggest that it may have capabilities for similarly versatile chemistry as the extensively studied diiron-carboxylate cofactor. The presently identified members of the manganese/iron-carboxylate proteins are all sequence homologues of the radical-generating R2 subunit of class I ribonucleotide reductase, canonically a diiron protein. They are also commonly misannotated...
Source: Journal of Biological Inorganic Chemistry : JBIC - November 16, 2009 Category: Chemistry Authors: Högbom M Tags: J Biol Inorg Chem Source Type: journals

Steric hindrance effect of the equatorial ligand on Fe(IV)O and Ru(IV)O complexes: a density functional study.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The geometric structures and mechanisms for hydrogen abstraction from cyclohexane for four high-valent complexes, [Fe(IV)(O)(TMC)(NCMe)](2+) (where TMC is 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane; 1-NCMe), the inverted isomer [Fe(IV)(NCMe)(TMC)(O)](2+) (2-NCMe), [Ru(IV)(O)(TMC)(NCMe)](2+) (the ruthenium analogue of 1-NCMe; 3-NCMe), and the inverted isomer [Ru(IV)(NCMe)(TMC)(O)](2+) (4-NCMe), were investigated using density functional theory. The axial NCMe ligand was found to be sterically more hindered in 2-NCMe than in 1-NCMe, which is in accord with the calculated results that the Fe-L(axial) distance ...
Source: Journal of Biological Inorganic Chemistry : JBIC - November 15, 2009 Category: Chemistry Authors: Wang Y, Han K Tags: J Biol Inorg Chem Source Type: journals

Changes in non-core regions stabilise plastocyanin from the thermophilic cyanobacterium Phormidium laminosum.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report a theoretical investigation on the different stabilities of two plastocyanins. The first one belongs to the thermophilic cyanobacterium Phormidium laminosum and the second one belongs to its mesophilic relative Synechocystis sp. These proteins share the same topology and secondary-structure elements; however, the melting temperatures of their oxidised species differ by approximately 15 K. Long-time-scale molecular dynamics simulations, performed at different temperatures, show that the thermophilic protein optimises a set of intramolecular interactions (interstrand hydrogen bonding, salt bridging and hydrophobic ...
Source: Journal of Biological Inorganic Chemistry : JBIC - November 14, 2009 Category: Chemistry Authors: Muñoz-López FJ, Raugei S, De la Rosa MA, Díaz-Quintana AJ, Carloni P Tags: J Biol Inorg Chem Source Type: journals

Protein recognition in ferredoxin-P450 electron transfer in the class I CYP199A2 system from Rhodopseudomonas palustris.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CYP199A2 from Rhodopseudomonas palustris CGA009 is a heme monooxygenase that catalyzes the oxidation of para-substituted benzoic acids. CYP199A2 activity is reconstituted by a class I electron transfer chain consisting of the associated [2Fe-2S] ferredoxin palustrisredoxin (Pux) and a flavoprotein palustrisredoxin reductase (PuR). Another [2Fe-2S] ferredoxin, palustrisredoxin B (PuxB; RPA3956) has been identified in the genome. PuxB shares sequence identity and motifs with vertebrate-type ferredoxins involved in Fe-S cluster assembly but also 50% identity with Pux and it mediates electron transfer from PuR to CYP199A2,...
Source: Journal of Biological Inorganic Chemistry : JBIC - November 11, 2009 Category: Chemistry Authors: Bell SG, Xu F, Johnson EO, Forward IM, Bartlam M, Rao Z, Wong LL Tags: J Biol Inorg Chem Source Type: journals

Cell biology of copper.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19882181 [PubMed - as supplied by publisher] (Source: Journal of Biological Inorganic Chemistry : JBIC)
Source: Journal of Biological Inorganic Chemistry : JBIC - October 31, 2009 Category: Chemistry Authors: Culotta V Tags: J Biol Inorg Chem Source Type: journals

Copper redistribution in Atox1-deficient mouse fibroblast cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Quantitative synchrotron X-ray fluorescence (SXRF) imaging of adherent mouse fibroblast cells deficient in antioxidant-1 (Atox1), a metallochaperone protein responsible for delivering Cu to cuproenzymes in the trans-Golgi network, revealed striking differences in the subcellular Cu distribution compared with wild-type cells. Whereas the latter showed a pronounced perinuclear localization of Cu, the Atox1-deficient cells displayed a mostly unstructured and diffuse distribution throughout the entire cell body. Comparison of the SXRF elemental maps for Zn and Fe of the same samples showed no marked differences between the...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 29, 2009 Category: Chemistry Authors: McRae R, Lai B, Fahrni CJ Tags: J Biol Inorg Chem Source Type: journals

Copper in the brain and Alzheimer's disease.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Alzheimer's disease (AD) is the most common form of neurodegenerative disease. The brain is particularly vulnerable to oxidative damage induced by unregulated redox-active metals such as copper and iron, and the brains of AD patients display evidence of metal dyshomeostasis and increased oxidative stress. The colocalisation of copper and amyloid beta (Abeta) in the glutamatergic synapse during NMDA-receptor-mediated neurotransmission provides a microenvironment favouring the abnormal interaction of redox-potent Abeta with copper under conditions of copper dysregulation thought to prevail in the AD brain, resulting in t...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 28, 2009 Category: Chemistry Authors: Hung YH, Bush AI, Cherny RA Tags: J Biol Inorg Chem Source Type: journals

Neuroprotective action of FK-506 (tacrolimus) after seizures induced with pilocarpine: quantitative and topographic elemental analysis of brain tissue.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the present work, X-ray fluorescence microscopy with a synchrotron source for the exciting radiation was applied for topographic and quantitative elemental analysis of rat brain tissue in pilocarpine-induced epilepsy and neuroprotection with FK-506. The mass per unit area of the elements P, S, Cl, K, Ca, Fe, Cu, Zn, Se, Br, and Rb was determined in four fields of the hippocampal formation (sectors 1 and 3 of Ammon's horn-CA1, CA3; dentate gyrus; hilus of dentate gyrus) and the parietal cortex. The results obtained for epileptic rats treated with FK-506 (SNF) were compared with data obtained previously for epileptic ...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 28, 2009 Category: Chemistry Authors: Chwiej J, Janeczko K, Marciszko M, Czyzycki M, Rickers K, Setkowicz Z Tags: J Biol Inorg Chem Source Type: journals

Role of a novel disulfide bridge within the all-beta fold of soluble Rieske proteins.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Rieske proteins and Rieske ferredoxins are present in the three domains of life and are involved in a variety of cellular processes. Despite their functional diversity, these small Fe-S proteins contain a highly conserved all-beta fold, which harbors a [2Fe-2S] Rieske center. We have identified a novel subtype of Rieske ferredoxins present in hyperthermophilic archaea, in which a two-cysteine conserved SKTPCX((2-3))C motif is found at the C-terminus. We establish that in the Acidianus ambivalens representative, Rieske ferredoxin 2 (RFd2), these cysteines form a novel disulfide bond within the Rieske fold, which can be ...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 28, 2009 Category: Chemistry Authors: Botelho HM, Leal SS, Veith A, Prosinecki V, Bauer C, Fröhlich R, Kletzin A, Gomes CM Tags: J Biol Inorg Chem Source Type: journals

Human copper transporter Ctr1 is functional in Drosophila, revealing a high degree of conservation between mammals and insects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Living cells have to carefully control the intracellular concentration of trace metals, especially of copper, which is at the same time essential but owing to its redox activity can also facilitate generation of reactive oxygen species. Mammals have two related copper transporters, Ctr1 and Ctr2, with Ctr1 playing the major role. The fruit fly Drosophila has three family members, termed Ctr1A, Ctr1B, and Ctr1C. Ctr1A is expressed throughout development, and a null mutation causes lethality at an early stage. Ctr1B ensures efficient copper uptake in the intestinal tract, whereas Ctr1C is mainly expressed in male gonads....
Source: Journal of Biological Inorganic Chemistry : JBIC - October 25, 2009 Category: Chemistry Authors: Hua H, Georgiev O, Schaffner W, Steiger D Tags: J Biol Inorg Chem Source Type: journals

Structural organization of human Cu-transporting ATPases: learning from building blocks.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Copper-transporting ATPases (Cu-ATPases) ATP7A and ATP7B play an essential role in human physiological function. Their primary function is to deliver copper to the secretory pathway and export excess copper from the cell for removal or further utilization. Cells employ Cu-ATPases in numerous physiological processes that include the biosynthesis of copper-dependent enzymes, lactation, and response to hypoxia. Biochemical studies of human Cu-ATPases and their orthologs have demonstrated that Cu-ATPases share many common structural and mechanistic characteristics with other members of the P-type ATPase family. Nevertheles...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 23, 2009 Category: Chemistry Authors: Barry AN, Shinde U, Lutsenko S Tags: J Biol Inorg Chem Source Type: journals

The metal ion requirements of Arabidopsis thaliana Glx2-2 for catalytic activity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In an effort to better understand the structure, metal content, the nature of the metal centers, and enzyme activity of Arabidopsis thaliana Glx2-2, the enzyme was overexpressed, purified, and characterized using metal analyses, kinetics, and UV-vis, EPR, and (1)H NMR spectroscopies. Glx2-2-containing fractions that were purple, yellow, or colorless were separated during purification, and the differently colored fractions were found to contain different amounts of Fe and Zn(II). Spectroscopic analyses of the discrete fractions provided evidence for Fe(II), Fe(III), Fe(III)-Zn(II), and antiferromagnetically coupled Fe(I...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 15, 2009 Category: Chemistry Authors: Limphong P, McKinney RM, Adams NE, Makaroff CA, Bennett B, Crowder MW Tags: J Biol Inorg Chem Source Type: journals

Multicopper oxidases: a workshop on copper coordination chemistry, electron transfer, and metallophysiology.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Multicopper oxidases (MCOs) are unique among copper proteins in that they contain at least one each of the three types of biologic copper sites, type 1, type 2, and the binuclear type 3. MCOs are descended from the family of small blue copper proteins (cupredoxins) that likely arose as a complement to the heme-iron-based cytochromes involved in electron transport; this event corresponded to the aerobiosis of the biosphere that resulted in the conversion of Fe(II) to Fe(III) as the predominant redox state of this essential metal and the solubilization of copper from Cu(2)S to Cu(H(2)O)( n ) (2+). MCOs are encoded in gen...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 8, 2009 Category: Chemistry Authors: Kosman DJ Tags: J Biol Inorg Chem Source Type: journals

Posttranslational regulation of copper transporters.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Copper is an essential but potentially harmful trace element involved in many enzymatic processes that require redox chemistry. Cellular copper homeostasis in mammals is predominantly maintained by posttranslational regulation of copper import and export through the copper import proteins hCTR1 and hCTR2 and the copper exporters ATP7A and ATP7B. Regulation of copper uptake and export is achieved by modulation of transporter expression, copper-dependent and copper-independent trafficking of the different transporters, posttranslational modifications, and interacting proteins. In this review we systematically discuss the...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 7, 2009 Category: Chemistry Authors: van den Berghe PV, Klomp LW Tags: J Biol Inorg Chem Source Type: journals

Kinetics and mechanism of exogenous anion exchange in FeFbpA-NTA: significance of periplasmic anion lability and anion binding activity of ferric binding protein A.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The bacterial transferrin ferric binding protein A (FbpA) requires an exogenous anion to facilitate iron sequestration, and subsequently to shuttle the metal across the periplasm to the cytoplasmic membrane. In the diverse conditions of the periplasm, numerous anions are known to be present. Prior in vitro experiments have demonstrated the ability of multiple anions to fulfill the synergistic iron-binding requirement, and the identity of the bound anion has been shown to modulate important physicochemical properties of iron-bound FbpA (FeFbpA). Here we address the kinetics and mechanism of anion exchange for the FeFbpA...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 7, 2009 Category: Chemistry Authors: Heymann JJ, Gabričević M, Mietzner TA, Crumbliss AL Tags: J Biol Inorg Chem Source Type: journals

Tumor cellular proteasome inhibition and growth suppression by 8-hydroxyquinoline and clioquinol requires their capabilities to bind copper and transport copper into cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have previously reported that when mixed with copper, 8-hydroxyquinoline (8-OHQ) and its analog clioquinol (CQ) inhibited the proteasomal activity and proliferation in cultured human cancer cells. CQ treatment of high-copper-containing human tumor xenografts also caused cancer suppression, associated with proteasome inhibition in vivo. However, the nature of the copper dependence of these events has not been elucidated experimentally. In the current study, using chemical probe molecules that mimic the structures of 8-OHQ and CQ, but have no copper-binding capability, we dissected the complex cellular processes elici...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 6, 2009 Category: Chemistry Authors: Zhai S, Yang L, Cui QC, Sun Y, Dou QP, Yan B Tags: J Biol Inorg Chem Source Type: journals

Regulation of copper transport in Arabidopsis thaliana: a biochemical oscillator?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plants are among the most versatile higher eukaryotes in accommodating environmental copper availability to largely variable demands. In particular, copper deficiency in soils is a threat for plant survival since it mostly affects reproductive structures. One of the strategies that plant cells use to overcome this situation is to increase copper levels by expressing high-affinity copper transporters delivering the metal to the cytosol. In this minireview, we discuss recent advances in the structure, function, and regulation of the CTR/COPT family of copper transporters, and pay special attention to the Arabidopsis thal...
Source: Journal of Biological Inorganic Chemistry : JBIC - October 1, 2009 Category: Chemistry Authors: Peñarrubia L, Andrés-Colás N, Moreno J, Puig S Tags: J Biol Inorg Chem Source Type: journals

Response of Gram-positive bacteria to copper stress.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Gram-positive bacteria Enterococcus hirae, Lactococcus lactis, and Bacillus subtilis have received wide attention in the study of copper homeostasis. Consequently, copper extrusion by ATPases, gene regulation by copper, and intracellular copper chaperoning are understood in some detail. This has provided profound insight into basic principles of how organisms handle copper. It also emerged that many bacterial species may not require copper for life, making copper homeostatic systems pure defense mechanisms. Structural work on copper homeostatic proteins has given insight into copper coordination and bonding and has...
Source: Journal of Biological Inorganic Chemistry : JBIC - September 22, 2009 Category: Chemistry Authors: Solioz M, Abicht HK, Mermod M, Mancini S Tags: J Biol Inorg Chem Source Type: journals

Copper and zinc bis(thiosemicarbazonato) complexes with a fluorescent tag: synthesis, radiolabelling with copper-64, cell uptake and fluorescence studies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The synthesis of new copper(II) bis(thiosemicarbazonato) complexes with an appended pyrene chromophore and their zinc(II) analogues is reported. The new proligands and their copper(II) and zinc(II) complexes were characterised by a combination of NMR, EPR, high performance liquid chromatography, mass spectrometry, electronic spectroscopy and electrochemical measurements. The new copper(II) complexes are fluorescent as a consequence of an appended pyrene substituent that is separated from the sulphur coordinating to the metal ion by five bonds. The emission from the pyrene substituent is concentration- and solvent-depen...
Source: Journal of Biological Inorganic Chemistry : JBIC - September 21, 2009 Category: Chemistry Authors: Lim S, Price KA, Chong SF, Paterson BM, Caragounis A, Barnham KJ, Crouch PJ, Peach JM, Dilworth JR, White AR, Donnelly PS Tags: J Biol Inorg Chem Source Type: journals

Cisplatin interaction with phosphatidylserine bilayer studied by solid-state NMR spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, (13)C, (31)P, and (15)N solid-state NMR spectra of 1-palmitoyl-2-oleoyl phosphatidylserine (POPS) bilayers, POPS bilayers with 10 mol% cisplatin, and POPS bilayers with 30 mol% cisplatin were acquired. In addition, (15)N{(31)P} rotational echo double resonance spectra of POPS bilayers with 30 mol% cisplatin were acquired. The data demonstrate that the serine head group of phosphatidylserine binds to the aquated form of cisplatin and that cisplatin release of ammine takes place. It appears that the cisplatin release of ammine is followed by another cisplatin-POPS complex formation, possibly with cisplatin bin...
Source: Journal of Biological Inorganic Chemistry : JBIC - September 18, 2009 Category: Chemistry Authors: Jensen M, Bjerring M, Nielsen NC, Nerdal W Tags: J Biol Inorg Chem Source Type: journals

A combined computational and experimental investigation of the [2Fe-2S] cluster in biotin synthase.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Biotin synthase was the first example of what is now regarded as a distinctive enzyme class within the radical S-adenosylmethionine superfamily, the members of which use Fe/S clusters as the sulphur source in radical sulphur insertion reactions. The crystal structure showed that this enzyme contains a [2Fe-2S] cluster with a highly unusual arginine ligand, besides three normal cysteine ligands. However, the crystal structure is at such a low resolution that neither the exact coordination mode nor the role of this exceptional ligand has been elucidated yet, although it has been shown that it is not essential for enzyme ...
Source: Journal of Biological Inorganic Chemistry : JBIC - September 18, 2009 Category: Chemistry Authors: Fuchs MG, Meyer F, Ryde U Tags: J Biol Inorg Chem Source Type: journals

Structure of the Ni(II) complex of Escherichia coli peptide deformylase and suggestions on deformylase activities depending on different metal(II) centres.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Crystal structures of polypeptide deformylase (PDF) of Escherichia coli with nickel(II) replacing the native iron(II) have been solved with chloride and formate as metal ligands. The chloro complex is a model for the correct protonation state of the hydrolytic hydroxo ligand and the protonated status of the Glu133 side chain as part of the hydrolytic mechanism. The ambiguity that recently some PDFs have been identified with Zn(2+) ion as the active-site centre whereas others are only active with Fe(2+) (or Co(2+), Ni(2+)) is discussed with respect to Lewis acid criteria of the metal ion and substrate activation by the ...
Source: Journal of Biological Inorganic Chemistry : JBIC - September 3, 2009 Category: Chemistry Authors: Yen NT, Bogdanović X, Palm GJ, Kühl O, Hinrichs W Tags: J Biol Inorg Chem Source Type: journals

Crystal structures of Streptococcus pyogenes Dpr reveal a dodecameric iron-binding protein with a ferroxidase site.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
DNA-binding protein from starved cells (Dps)-like proteins are key factors involved in oxidative stress protection in bacteria. They bind and oxidize iron, thus preventing the formation of harmful reactive oxygen species that can damage biomolecules, particularly DNA. Dps-like proteins are composed of 12 identical subunits assembled in a spherical structure with a hollow central cavity. The iron oxidation occurs at 12 intersubunit sites located at dimer interfaces. Streptococcus pyogenes Dps-like peroxide resistance protein (Dpr) has been previously found to protect the catalase-lacking S. pyogenes bacterium from oxida...
Source: Journal of Biological Inorganic Chemistry : JBIC - September 1, 2009 Category: Chemistry Authors: Haikarainen T, Tsou CC, Wu JJ, Papageorgiou AC Tags: J Biol Inorg Chem Source Type: journals

Scanning chimeragenesis: the approach used to change the substrate selectivity of fatty acid monooxygenase CYP102A1 to that of terpene omega-hydroxylase CYP4C7.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CYP102A1 is a highly active, water-soluble, bacterial monooxygenase enzyme that contains both substrate-binding heme and diflavin reductase subunits, both in a single polypeptide. Recently we developed a procedure which uses the known structure of the substrate-bound heme domain of CYP102A1 and its sequence homology with a cytochrome P450 of unknown structure, both of which react with a common substrate but produce different products, to create recombinant enzymes which have substrate selectivity different from that of CYP102A1, and produce the product of the enzyme of unknown structure. Insect CYP4C7, a terpene hydrox...
Source: Journal of Biological Inorganic Chemistry : JBIC - August 29, 2009 Category: Chemistry Authors: Chen CK, Berry RE, Shokhireva TK, Murataliev MB, Zhang H, Walker FA Tags: J Biol Inorg Chem Source Type: journals

ENDOR and ESEEM investigation of the Ni-containing superoxide dismutase.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Superoxide dismutases (SODs) protect cells against oxidative stress by disproportionating O(2) (-) to H(2)O(2) and O(2). The recent finding of a nickel-containing SOD (Ni-SOD) has widened the diversity of SODs in terms of metal contents and SOD catalytic mechanisms. The coordination and geometrical structure of the metal site and the related electronic structure are the keys to understanding the dismutase mechanism of the enzyme. We performed Q-band (14)N,(1/2)H continuous wave (CW) and pulsed electron-nuclear double resonance (ENDOR) and X-band (14)N electron spin echo envelope modulation (ESEEM) on the resting-state ...
Source: Journal of Biological Inorganic Chemistry : JBIC - August 25, 2009 Category: Chemistry Authors: Lee HI, Lee JW, Yang TC, Kang SO, Hoffman BM Tags: J Biol Inorg Chem Source Type: journals

Serum-protein interactions with anticancer Ru(III) complexes KP1019 and KP418 characterized by EPR.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, electron paramagnetic resonance (EPR) measurements, combined with incubation under physiological conditions, and separation of protein-bound fractions, have been used to characterize the interactions of these complexes with human serum albumin (hsA), human serum transferrin (hsTf) apoprotein, and whole human serum. The strong EPR signals observed in these experiments demonstrate that both complexes are primarily retained in the 3+ oxidation state in the presence of serum components. Rapid, noncovalent binding of KP1019 was observed in the presence of both hsA and serum, indicating that the predominant intera...
Source: Journal of Biological Inorganic Chemistry : JBIC - August 25, 2009 Category: Chemistry Authors: Cetinbas N, Webb MI, Dubland JA, Walsby CJ Tags: J Biol Inorg Chem Source Type: journals

Differences in coordination states of substituted tyrosine residues and quaternary structures among hemoglobin M probed by resonance Raman spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Among the four types of hemoglobin (Hb) M with a substitution of a tyrosine (Tyr) for either the proximal (F8) or distal (E7) histidine in the alpha or beta subunits, only Hb M Saskatoon (betaE7Tyr) assumes a hexacoordinate structure and its abnormal subunits can be reduced readily by methemoglobin (metHb) reductase. This is distinct from the other three M Hbs. To gain new insight into the cause of the difference, we examined the ionization states of E7 and F8 Tyrs by UV resonance Raman (RR) spectroscopy and Fe-O(Tyr) bonding by visible RR spectroscopy. Hb M Iwate (alphaF8Tyr), Hb M Boston (alphaE7Tyr), and Hb M Hyde P...
Source: Journal of Biological Inorganic Chemistry : JBIC - August 22, 2009 Category: Chemistry Authors: Aki Y, Nagai M, Nagai Y, Imai K, Aki M, Sato A, Kubo M, Nagatomo S, Kitagawa T Tags: J Biol Inorg Chem Source Type: journals

Structural and mechanistic insights into the oxy form of tyrosinase from molecular dynamics simulations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The first, long time scale (16-ns) ligand field molecular dynamics (LFMD) simulations of the oxy form of tyrosinase are reported. The calculations use our existing type 3 copper force field for the peroxido-bridged [Cu(2)O(2)](2+) unit which is here translated from MMFF into the AMBER format together with a new charge scheme. The protein secondary and tertiary structures are not significantly altered by removing the 'caddie' protein, ORF378, which must be bound to tyrosinase before crystals will grow. A comprehensive principal component analysis of the Cartesian coordinates from the final 8 ns shows that the protein ba...
Source: Journal of Biological Inorganic Chemistry : JBIC - August 18, 2009 Category: Chemistry Authors: Deeth RJ, Diedrich C Tags: J Biol Inorg Chem Source Type: journals

Reactivity of platinum-based antitumor drugs towards a Met- and His-rich 20mer peptide corresponding to the N-terminal domain of human copper transporter 1.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cellular uptake of platinum-based antitumor drugs is a critical step in the mechanism of the drug action and associated resistance, and deeper understanding of this step may inspire development of novel methods for new drugs with reduced resistance. Human copper transporter 1 (hCtr1), a copper influx protein, was recently found to facilitate the cellular entry of several platinum drugs. In the work reported here, we constructed a Met- and His-rich 20mer peptide (hCtr1-N20) corresponding to the N-terminal domain of hCtr1, which is the essential domain of hCtr1 for transporting platinum drugs. The interactions of the pep...
Source: Journal of Biological Inorganic Chemistry : JBIC - August 7, 2009 Category: Chemistry Authors: Wu Z, Liu Q, Liang X, Yang X, Wang N, Wang X, Sun H, Lu Y, Guo Z Tags: J Biol Inorg Chem Source Type: journals

A peroxynitrite complex of copper: formation from a copper-nitrosyl complex, transformation to nitrite and exogenous phenol oxidative coupling or nitration.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Discussions include the structures (including electronic description) of the copper-nitrosyl and copper-peroxynitrite complexes and the formation of the latter, based on density functional theory calculations and accompanying spectroscopic data. PMID: 19662443 [PubMed - as supplied by publisher] (Source: Journal of Biological Inorganic Chemistry : JBIC)
Source: Journal of Biological Inorganic Chemistry : JBIC - August 6, 2009 Category: Chemistry Authors: Park GY, Deepalatha S, Puiu SC, Lee DH, Mondal B, Narducci Sarjeant AA, Del Rio D, Pau MY, Solomon EI, Karlin KD Tags: J Biol Inorg Chem Source Type: journals

SBIC news. A note from the President.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19636602 [PubMed - in process] (Source: Journal of Biological Inorganic Chemistry : JBIC)
Source: Journal of Biological Inorganic Chemistry : JBIC - July 30, 2009 Category: Chemistry Authors: Hambley T Tags: J Biol Inorg Chem Source Type: journals

Immobilization of the hyperthermophilic hydrogenase from Aquifex aeolicus bacterium onto gold and carbon nanotube electrodes for efficient H(2) oxidation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report high catalytic currents for H(2) oxidation up to 1 mA cm(-2), 10 times higher than at the bare electrode. Interestingly, high stability of the direct catalytic process was observed when encapsulating A. aeolicus [NiFe]-hase I into a carboxylic functionalized single walled carbon nanotube network. This suggests a peculiar interaction between the enzyme and the electrode material. The parameters that governed the orientation of the enzyme before electron transfer were thus investigated using self-assembled-monolayer gold electrodes. No control of the orientation by the charge or the hydrophobicity of the interface ...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 21, 2009 Category: Chemistry Authors: Luo X, Brugna M, Tron-Infossi P, Giudici-Orticoni MT, Lojou E Tags: J Biol Inorg Chem Source Type: journals

Catalysis of iron core formation in Pyrococcus furiosus ferritin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The hollow sphere-shaped 24-meric ferritin can store large amounts of iron as a ferrihydrite-like mineral core. In all subunits of homomeric ferritins and in catalytically active subunits of heteromeric ferritins a diiron binding site is found that is commonly addressed as the ferroxidase center (FC). The FC is involved in the catalytic Fe(II) oxidation by the protein; however, structural differences among different ferritins may be linked to different mechanisms of iron oxidation. Non-heme ferritins are generally believed to operate by the so-called substrate FC model in which the FC cycles by filling with Fe(II), oxi...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 21, 2009 Category: Chemistry Authors: Honarmand Ebrahimi K, Hagedoorn PL, Jongejan JA, Hagen WR Tags: J Biol Inorg Chem Source Type: journals

Biomimetic oxidative treatment of spruce wood studied by pyrolysis-molecular beam mass spectrometry coupled with multivariate analysis and (13)C-labeled tetramethylammonium hydroxide thermochemolysis: implications for fungal degradation of wood.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this work, pyrolysis-molecular beam mass spectrometry analysis coupled with principal components analysis and (13)C-labeled tetramethylammonium hydroxide thermochemolysis were used to study lignin oxidation, depolymerization, and demethylation of spruce wood treated by biomimetic oxidative systems. Neat Fenton and chelator-mediated Fenton reaction (CMFR) systems as well as cellulosic enzyme treatments were used to mimic the nonenzymatic process involved in wood brown-rot biodegradation. The results suggest that compared with enzymatic processes, Fenton-based treatment more readily opens the structure of the lignocel...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 20, 2009 Category: Chemistry Authors: Arantes V, Qian Y, Kelley SS, Milagres AM, Filley TR, Jellison J, Goodell B Tags: J Biol Inorg Chem Source Type: journals

Importance of dynamical processes in the coordination chemistry and redox conversion of copper amyloid-beta complexes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Interaction of Cu ions with the amyloid-beta (Abeta) peptide is linked to the development of Alzheimer's disease; hence, determining the coordination of Cu(I) and Cu(II) ions to Abeta and the pathway of the Cu(I)(Abeta)/Cu(II)(Abeta) redox conversion is of great interest. In the present report, we use the room temperature X-ray absorption near edge structure to show that the binding sites of the Cu(I) and Cu(II) complexes are similar to those previously determined from frozen-solution studies. More precisely, the Cu(I) is coordinated by the imidazole groups of two histidine residues in a linear fashion. However, an NMR...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 17, 2009 Category: Chemistry Authors: Hureau C, Balland V, Coppel Y, Solari PL, Fonda E, Faller P Tags: J Biol Inorg Chem Source Type: journals

NMR structural analysis of the soluble domain of ZiaA-ATPase and the basis of selective interactions with copper metallochaperone Atx1.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A Cu(I) metallochaperone, Atx1, interacts with the amino-terminal domain of a Cu(I)-transporting ATPase, PacS(N), but not with a domain of related Zn-transporting ATPase, ZiaA(N) in Synechocystis PCC 6803. This is thought to prevent ZiaA(N) from acquiring Cu(I), which it binds more tightly than Zn. Solution structures of Atx1, PacS(N), and the heterodimer were previously described. Here we report solution structural studies of the ZiaA(N) soluble domain. Apo-ZiaA(N) has a typical ferredoxin-like fold followed by an atypical 34 residues of unstructured polypeptide containing a His(7) motif. ZiaA(N) competes with the met...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 15, 2009 Category: Chemistry Authors: Banci L, Bertini I, Ciofi-Baffoni S, Poggi L, Vanarotti M, Tottey S, Waldron KJ, Robinson NJ Tags: J Biol Inorg Chem Source Type: journals

Uptake of diterbium transferrin, a potential multi-photon-excited microscopy probe, into human leukemia K562 cells via a transferrin-receptor-mediated process.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Our present study provided new evidence for diterbium transferrin (Tb(2)Tf) as a potential multi-photon-excited microscopy probe. It indicated that the Tb(2)Tf complex can be transported into human leukemia K562 cells via a process mediated by transferrin (Tf) receptors as an intact entity and with no obvious cellular toxicity. The supporting evidence includes the following. First, the transport kinetic behavior of Tb was compared with that of the Tf moiety. The Tb was determined by inductively coupled plasma mass spectrometry and Tf was determined by fluorescence activated cell sorting analysis. The kinetic synchroniz...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 14, 2009 Category: Chemistry Authors: Yuan L, Du P, Wang K, Yang XG Tags: J Biol Inorg Chem Source Type: journals

QM/MM investigation into binding of square-planar platinum complexes to DNA fragments.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A series of calculations employing hybrid quantum mechanics/molecular mechanics methods to explore the binding of square-planar complexes to fragments of DNA are reported. Methylated analogues of the parent compound cis-[Pt(en)Cl(2)], where en is ethylenediamine, show considerable variation in in vitro cytotoxicity depending on the number and position of methyl groups. Calculations reveal variations in the structure and the binding energy of adducts to single- and double-stranded fragments of DNA. Most such variations are relatively small, but the introduction of three or four methyls on nitrogen of ethylenediamine sig...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 8, 2009 Category: Chemistry Authors: Gkionis K, Platts JA Tags: J Biol Inorg Chem Source Type: journals

Kinetic and redox properties of MnP II, a major manganese peroxidase isoenzyme from Panus tigrinus CBS 577.79.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A manganese peroxidase (MnP) isoenzyme from Panus tigrinus CBS 577.79 was produced in a benchtop stirred-tank reactor and purified to apparent homogeneity. The purification scheme involving ultrafiltration, affinity chromatography on concanavalin-A Sepharose, and gel filtration led to a purified MnP, termed "MnP II," with a specific activity of 288 IU mg(-1) protein and a final yield of 22%. The enzyme turned out to be a monomeric protein with molecular mass of 50.5 kDa, pI of 4.07, and an extent of N-glycosylation of about 5.3% of the high-mannose type. The temperature and pH optima for the formation of malonate manga...
Source: Journal of Biological Inorganic Chemistry : JBIC - July 3, 2009 Category: Chemistry Authors: Petruccioli M, Frasconi M, Quaratino D, Covino S, Favero G, Mazzei F, Federici F, D'Annibale A Tags: J Biol Inorg Chem Source Type: journals

Chemistry, antiproliferative properties, tumor selectivity, and molecular mechanisms of novel gold(III) compounds for cancer treatment: a systematic study.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The antiproliferative properties of a group of 13 structurally diverse gold(III) compounds, including six mononuclear gold(III) complexes, five dinuclear oxo-bridged gold(III) complexes, and two organogold(III) compounds, toward several human tumor cell lines were evaluated in vitro using a systematic screening strategy. Initially all compounds were tested against a panel of 12 human tumor cell lines, and the best performers were tested against a larger 36-cell-line panel. Very pronounced antiproliferative properties were highlighted in most cases, with cytotoxic potencies commonly falling in the low micromolar-and eve...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 19, 2009 Category: Chemistry Authors: Casini A, Kelter G, Gabbiani C, Cinellu MA, Minghetti G, Fregona D, Fiebig HH, Messori L Tags: J Biol Inorg Chem Source Type: journals

Molecular dynamics simulations of mouse ferrochelatase variants: what distorts and orientates the porphyrin?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Molecular dynamics simulations of the wild-type and variant forms of the mouse ferrochelatase in complex with the product (haem) have been performed using the GROMOS96 force field, in the NpT ensemble. Ferrochelatase, the last enzyme in the catalytic pathway of the haem biosynthesis, catalyses the reaction of insertion of a ferrous ion into protoporphyrin IX by distorting the planar geometry of the latter reactant. The simulations presented aim at understanding the role of active-site residues in this catalytic process. Analysis of the simulation trajectories explains the consequences of the mutations introduced and sh...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 19, 2009 Category: Chemistry Authors: Szefczyk B, Cordeiro MN, Franco R, Gomes JA Tags: J Biol Inorg Chem Source Type: journals

Interaction between cyanobacterial copper chaperone Atx1 and zinc homeostasis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cyanobacterial Atx1 is a copper chaperone which interacts with two copper-transporting ATPases to assist copper supply to plastocyanin and cytochrome oxidase. ZiaA is a Zn(2+)-exporting ATPase and ziaA expression is regulated by ZiaR. Here we show that gene expression from the ziaA operator promoter, monitored using reverse transcriptase PCR and lacZ fusions, is elevated in Deltaatx1 mutants. Although Cu(+) tightly binds recombinant ZiaR in vitro, Cu(+) is less effective at dissociating ZiaR-DNA complexes than Zn(2+) and crucially ziaA expression responds to Zn(2+) but not copper in both wild-type and Deltaatx1 cells. ...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 19, 2009 Category: Chemistry Authors: Dainty SJ, Patterson CJ, Waldron KJ, Robinson NJ Tags: J Biol Inorg Chem Source Type: journals

Reaction of human metallothionein-3 with cisplatin and transplatin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Human metallothioneins, small cysteine- and metal-rich proteins, play an important role in the acquired resistance to platinum-based anticancer drugs. These proteins contain a M(II)(4)(CysS)(11) cluster and a M(II)(3)(CysS)(9) cluster localized in the alpha-domain and the beta-domain, respectively. The noninducible isoform metallothionein-3 (Zn(7)MT-3) is mainly expressed in the brain, but was found overexpressed in a number of cancer tissues. Since the structural properties of this isoform substantially differ from those of the ubiquitously occurring Zn(7)MT-1/Zn(7)MT-2 isoforms, the reactions of cis-diamminedichlorid...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 17, 2009 Category: Chemistry Authors: Karotki AV, Vašák M Tags: J Biol Inorg Chem Source Type: journals

Water-soluble molybdenocene complexes with both proliferative and antiproliferative effects on cancer cell lines and their binding interactions with human serum albumin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Two water-soluble molybdenocene complexes containing oxygen chelating ligands, maltolato and malonate, have been synthesized to elucidate the role of the ancillary ligands in the molybdenocene cytotoxic activity. The structural characterizations of these species by (1)H NMR and IR spectroscopies suggest that both molybdenocene complexes contain the ligands in a bidentate fashion and elemental analysis and mass spectrometry corroborate the proposed formula for the species to be Cp(2)Mo(malonate) and [Cp(2)Mo(maltolato)]Cl (Cp is cyclopentadienyl). Metal-albumin binding studies were pursued using UV-vis spectroscopy and ...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 17, 2009 Category: Chemistry Authors: Feliciano I, Matta J, Meléndez E Tags: J Biol Inorg Chem Source Type: journals

Solution structure and dynamics of S100A5 in the apo and Ca(2+)-bound states.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
S100A5 is a calcium binding protein of the S100 family, with one canonical and one S100-specific EF-hand motif per subunit. Although its function is still unknown, it has recently been reported to be one of the S100 proteins able to interact with the receptor for advanced glycation end products. The homodimeric solution structures of S100A5 in both the apo and the calcium(II)-loaded forms have been obtained, and show a conformational rearrangement upon calcium binding. This rearrangement involves, in particular, the hinge loop connecting the N-terminal and the C-terminal EF-hand domains, the reorientation of helix III ...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 17, 2009 Category: Chemistry Authors: Bertini I, Das Gupta S, Hu X, Karavelas T, Luchinat C, Parigi G, Yuan J Tags: J Biol Inorg Chem Source Type: journals

(1)H and (13)C NMR spectroscopic studies of the ferriheme resonances of three low-spin complexes of wild-type nitrophorin 2 and nitrophorin 2(V24E) as a function of pH.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The ferriheme resonances of the low-spin (S = 1/2) complexes of wild-type (wt) nitrophorin 2 (NP2) and its heme pocket mutant NP2(V24E) with imidazole (ImH), histamine (Hm), and cyanide (CN(-)) as the sixth ligand have been investigated by NMR spectroscopy as a function of pH (4.0-7.5). For the three wt NP2 complexes, the ratio of the two possible heme orientational isomers, A and B, remains almost unchanged (ratio of A:B approximately 1:6 to 1:5) over this wide pH range. However, strong chemical exchange cross peaks appear in the nuclear Overhauser effect spectroscopy/exchange spectroscopy (NOESY/EXSY) spectra for the...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 10, 2009 Category: Chemistry Authors: Yang F, Knipp M, Shokhireva TK, Berry RE, Zhang H, Walker FA Tags: J Biol Inorg Chem Source Type: journals

Orally available Mn porphyrins with superoxide dismutase and catalase activities.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, EUK-418 and several new analogs (the EUK-400 series) were synthesized and shown to exhibit superoxide dismutase, catalase, and peroxidase activities in vitro. Some also protected PC12 cells against staurosporine-induced cell death. All EUK-400 compounds were stable in simulated gastric fluid, and most were substantially more lipophilic than the salen Mn complexes EUK-189 and EUK-207, which lack oral activity. Pharmacokinetics studies demonstrate the presence of all EUK-400 series compounds in the plasma of rats after oral administration. These EUK-400 series compounds are potential oral therapeutic agents fo...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 5, 2009 Category: Chemistry Authors: Rosenthal RA, Huffman KD, Fisette LW, Damphousse CA, Callaway WB, Malfroy B, Doctrow SR Tags: J Biol Inorg Chem Source Type: journals

Synthesis, characterization, and reaction pathways for the formation of a GMP adduct of a cytotoxic thiocyanato ruthenium arene complex.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The organoruthenium complex [(eta(6)-hmb)Ru(en)(Cl)][PF(6)] (hmb is hexamethylbenzene, en is ethylenediamine) undergoes facile aquation and then reacts with KSCN in unbuffered solution to give the S-coordinated thiocyanato product [(eta(6)-hmb)Ru(en)(S-SCN)](+) which slowly converts to the thermodynamically favored N-bound complex [(eta(6)-hmb)Ru(en)(N-NCS)](+) (1 (+)). Complex 1 was synthesized and characterized by X-ray crystallography and mass spectrometry. Despite its lack of hydrolysis over 24 h, complex 1 exhibits moderate cytotoxicity (IC(50) 24 muM) towards the human ovarian cancer cell line A2780, comparable w...
Source: Journal of Biological Inorganic Chemistry : JBIC - June 4, 2009 Category: Chemistry Authors: Wang F, Habtemariam A, van der Geer EP, Deeth RJ, Gould R, Parsons S, Sadler PJ Tags: J Biol Inorg Chem Source Type: journals

Recent developments of the quantum chemical cluster approach for modeling enzyme reactions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The quantum chemical cluster approach for modeling enzyme reactions is reviewed. Recent applications have used cluster models much larger than before which have given new modeling insights. One important and rather surprising feature is the fast convergence with cluster size of the energetics of the reactions. Even for reactions with significant charge separation it has in some cases been possible to obtain full convergence in the sense that dielectric cavity effects from outside the cluster do not contribute to any significant extent. Direct comparisons between quantum mechanics (QM)-only and QM/molecular mechanics (M...
Source: Journal of Biological Inorganic Chemistry : JBIC - May 31, 2009 Category: Chemistry Authors: Siegbahn PE, Himo F Tags: J Biol Inorg Chem Source Type: journals