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31 records returned

PpoC from Aspergillus nidulans is a Fusion Protein with one active HemeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In Aspergillus nidulans psi factor producing oxygenases (Ppos) are required for the production of so-called psi factors (precocious sexual inducer) - compounds that control balance between the sexual and asexual life cycle of the fungus. The genome of A. nidulans harbours three different ppo genes: ppoA, ppoB and ppoC. For all three enzymes two different heme containing domains are predicted: a fatty acid heme peroxidase/dioxygenase domain for the N-terminal region and a P450 heme thiolate domain for the C-terminal region. While PpoA was shown to use both heme domains for its bifunctional catalytic activity (linoleic acid ...
Source: BJ Plant - October 30, 2009 Category: Biochemistry Authors: F Brodhun, S Schneider, C Göbel, E Hornung, I Feussner Tags: BJ Signal Source Type: journals

Threonine at position 306 of the KAT1 potassium channel is essential for channel activity and is a target site for ABA-activated SnRK2/OST1/SnRK2.6 protein kinaseEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we have demonstrated that the carboxyl-terminus region of KAT1 acts as a phosphorylation target for the Arabidopsis calcium-independent, ABA-activated protein kinase SnRK2.6. This was confirmed by LC-MS/MS analysis, which showed that KAT1 Thr306 and Thr308 residues were modified by phosphorylation. The role of these specific residues was examined by single point mutation and measurement of KAT1 channel activities in Xenopus oocyte and yeast systems. Modification of Thr308 had minimal effect on KAT1 activity. On the other hand, modification of Thr306 reduced K+ transport uptake activity of KAT1 in both...
Source: BJ Plant - September 27, 2009 Category: Biochemistry Authors: A Sato, Y Sato, Y Fukao, M Fujiwara, T Umezawa, K Shinozaki, T Hibi, M Taniguchi, H Miyake, D B. Goto, N Uozumi Tags: BJ Signal Source Type: journals

EIN2, the central regulator of ethylene signalling, is localised at the ER membrane where it interacts with the ethylene receptor ETR1Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Genetic studies have identified the membrane protein Ethylene Insensitive 2 (EIN2) as a central component of ethylene signalling in Arabidopsis. In addition, EIN2 might take part in multiple hormone signalling pathways and in responses to pathogens as demonstrated by recent genetic and biochemical studies. Here we show, by an integrated approach of in vivo and in vitro fluorescence techniques, that EIN2 is localised at the ER membrane where it shows specific interaction with the ethylene receptor protein ETR1. (Source: BJ Plant)
Source: BJ Plant - September 20, 2009 Category: Biochemistry Authors: M MA Bisson, A Bleckmann, S Allekotte, G Groth Tags: BJ Plant Source Type: journals

Bifunctional cytosolic UDP-glucose 4-epimerases catalyze the interconversion between UDP-D-xylose and UDP-L-arabinose in plantsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
UDP-sugars serve as substrates in the synthesis of cell wall polysaccharides and are themselves generated through sequential interconversion reactions from UDP-glucose (UDP-Glc) as the starting substrate in the cytosol and the Golgi apparatus. For this study, a soluble enzyme with UDP-xylose (UDP-Xyl) 4-epimerase activity was purified about 300-fold from pea (Pisum sativum L.) sprouts by conventional chromatography. The N-terminal amino acid sequence of the enzyme revealed that it is encoded by a predicted UDP-Glc 4-epimerase gene, PsUGE1, and distinct from UDP-Xyl 4-epimerase localized in the Golgi apparatus. Recombinant ...
Source: BJ Plant - September 14, 2009 Category: Biochemistry Authors: T Kotake, R Takata, R Verma, M Takaba, D Yamaguchi, T Orita, S Kaneko, K Matsuoka, T Koyama, W Reiter, Y Tsumuraya Tags: BJ Plant Source Type: journals

Phenylalanine ammonia-lyase from tobacco (Nicotiana tabacum)-characterization of the four tobacco PAL genes and active heterotetrameric enzymesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
L-Phenylalanine ammonia-lyase (PAL), the first enzyme of phenylpropanoid biosynthesis, is often encoded by multigene families in plants. A PCR-based approach was used to isolate cDNA clones corresponding to the four PAL genes of tobacco (Nicotiana tabacum). By careful comparison of cDNA and genomic clones, a new PAL gene (PAL4) was defined. PCR-amplification of PAL sequences from cDNA led to the generation of chimeric clones between PAL1 and PAL4, and incorrect annotation of PAL4 ESTs as PAL1 in the EST database has given rise to a randomly shuffled tentative consensus sequence. The PAL2 previously described in the literat...
Source: BJ Plant - September 1, 2009 Category: Biochemistry Authors: A I Reichert, X He, R A Dixon Tags: BJ Plant Source Type: journals

Conditions of endoplasmic reticulum stress stimulate lipid droplet formation in Saccharomyces cerevisiaeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lipid droplets (LDs) are cellular organelles which can be found in nearly all eukaryotic cells. Despite their importance in cell biology as highlighted by their implication in many devastating diseases, the mechanism underlying LD biogenesis remains largely unknown. Here we report that conditions of endoplasmic reticulum (ER) stress stimulate LD formation in Saccharomyces cerevisiae. We found that LDs accumulated in yeast mutants with compromised protein glycosylation or ER-associated protein degradation. Moreover, Tunicamycin and Brefeldin A, agents which induce ER stress were found to stimulate LD formation. In contrast ...
Source: BJ Plant - August 25, 2009 Category: Biochemistry Authors: W Fei, H Wang, X Fu, C Bielby, H Yang Tags: BJ Metabolism Source Type: journals

The eukaryotic GCP1 is a conserved mitochondrial protein required for progression of embryo development beyond the globular stage in Arabidopsis thalianaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this report on GCP1-type proteins from eukaryotic organisms we demonstrate that GCP1 is a mitochondrial protein in Homo sapiens (called here GCP1/OSGEPL1) and Arabidopsis thaliana that is located/anchored to the inner mitochondrial membrane. Analysis of mRNA and protein levels revealed that the expression of GCP1/OSGEPL1 in A. thaliana and H. sapiens is tissue- and organ-specific and depends on developmental stage, suggesting a more specialized function for this protein. We show that homozygous A. thaliana GCP1 T-DNA insertion lines are embryo-lethal. Embryos in homozygous seeds are arrested at the globular stage and fa...
Source: BJ Plant - August 20, 2009 Category: Biochemistry Authors: K Haussuehl, P F Huesgen, M Meier, P Dessi, E Glaser, J Adamski, I Adamska Tags: BJ Plant Source Type: journals

A novel variant of ferredoxin-dependent sulfite reductase having preferred substrate specificity for nitrite in Cyanidioschyzon merolaeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plant nitrite reductase (NiR) and sulfite reductase (SiR) have common features in structure and function. Both enzymes are generally distinguished in terms of substrate specificity for nitrite and sulfite. The Cyanidioschyzon merolae genome encodes two SiR homologs (CmSiRA and CmSiRB), but no NiR homolog. The facts that most known SiRs have a low nitrite-reducing activity and that CmSiRB is mapped between the genes for nitrate transporter and nitrate reductase implied that CmSiRB could have a potential function as a nitrite-reducing enzyme. To verify this hypothesis, we produced a recombinant form of CmSiRB and characteriz...
Source: BJ Plant - July 20, 2009 Category: Biochemistry Authors: K Sekine, Y Sakakibara, T Hase, N Sato Tags: BJ Plant Source Type: journals

The NRAMP6 metal transporter contributes to cadmium toxicityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Natural Resistance Associated Macrophage Protein (NRAMP) homologues are evolutionarily conserved divalent metal transporters. In Arabidopsis, AtNRAMP3 and AtNRAMP4 play a key role in iron nutrition of the germinating plantlet by remobilizing vacuolar Fe stores. Here we describe the molecular and physiological characterization of AtNRAMP6. AtNRAMP6 is predominantly expressed in the dry seed embryo and to a lesser extent in aerial parts. Its promoter activity is found diffusely distributed in cotyledons and hypocotyls as well as in the vascular tissue region of leaf and flower. We show that AtNRAMP6 transcript coexists with ...
Source: BJ Plant - June 21, 2009 Category: Biochemistry Authors: R Cailliatte, B Lapeyre, J Briat, S Mari, C Curie Tags: BJ Plant Source Type: journals

A cotton kinesin GhKCH2 interacts with both microtubules and microfilamentsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a cotton kinesin GhKCH2, which contains a calponin homology (CH) domain at the N-terminus, was analyzed in vitro and in vivo to understand its interaction with the two cytoskeletal elements. A specific antibody to GhKCH2 was prepared and used for immunolabeling experiments. Some GhKCH2 spots appeared along a few microtubules and microfilaments in developing cotton fibers. His-tagged N-terminus of GhKCH2 (GhKCH2-N) could coprecipitate with microfilaments and strongly bind to actin filaments at a ratio of monomeric actin:GhKCH2-N = 1:0.6. The full length GhKCH2 recombinant protein was shown to bind to and cros...
Source: BJ Plant - May 6, 2009 Category: Biochemistry Authors: T Xu, Z Qu, X Yang, X Qin, J Xiong, Y Wang, D Ren, G Liu Tags: BJ Plant Source Type: journals

Plasma membrane microdomains from hybrid aspen cells are involved in cell wall polysaccharide biosynthesisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report here the first isolation of DRMs from purified plasma membranes of a tree species, the hybrid aspen Populus tremula x tremuloides, and their biochemical characterization. Plasma membranes were solubilised with Triton X-100 and the resulting DRMs were isolated by flotation in sucrose gradients. The DRMs were enriched in sterols, sphingolipids and glycosylphosphatidylinositol-anchored proteins and thus exhibited similar properties as DRMs from other species. However, they contained key carbohydrate synthases involved in cell wall polysaccharide biosynthesis, namely callose ((1→3)-β-D-glucan) and cellu...
Source: BJ Plant - February 13, 2009 Category: Biochemistry Authors: L Bessueille, N Sindt, M Guichardant, S Djerbi, T T. Teeri, V Bulone Tags: BJ Plant Source Type: journals

Formation of macromolecular complex of carbonic anhydrases in the chloroplast of a marine diatom by the function of the C-terminal helixEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A β-type carbonic anhydrase, PtCA1, of the marine diatom Phaeodactylum tricornutum was previously shown to occur in the chloroplast as clumped particles on the girdle lamellae. A series of deletions was carried out on the PtCA1 gene, ptca1, at regions encode N- or C-terminal domains of the mature PtCA1. These deletion constructs were fused with the enhanced-green-fluorescent-protein gene, egfp, introduced, and expressed in the cells of P. tricornutum. All three types of N-terminal deletions, ∆52-63, ∆64-75, and ∆76-87 relative to the initiation methionine showed little interference with the part...
Source: BJ Plant - February 9, 2009 Category: Biochemistry Authors: Y Kitao, Y Matsuda Tags: BJ Plant Source Type: journals

Physical state of {kappa}-carrageenan modulates the mode of action of {kappa}-carrageenase from Pseudoalteromonas carrageenovoraEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Pseudoalteromonas carageenovora κ-carrageenase is a glycoside hydrolase involved in the bioconversion of carrageenans. Carrageenans are sulphated galactans that are densely packed in red algal cell walls. Previous crystallographic investigations revealed that the active site of κ-carrageenase has a tunnel-shaped topology, suggesting a processive mode of action for this enzyme. To biochemically characterise the enzymatic depolymerisation of κ-carrageenan, soluble and solid substrates (in both gel and powder forms) were incubated with P. carageenovora κ-carrageenase. The average molecular weight o...
Source: BJ Plant - February 5, 2009 Category: Biochemistry Authors: M Lemoine, P Nyvall Collén, W Helbert Tags: BJ Plant Source Type: journals

Single-myb histone proteins from Arabidopsis thaliana: Quantitative study of telomere binding specificity and kineticsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Proteins that bind telomeric DNA modulate the structure of chromosome ends and control telomere function and maintenance. It has been shown that Arabidopsis thaliana AtTRB proteins from the single-myb-histone (SMH) family selectively bind double-stranded telomeric DNA and interact with the telomeric protein AtPOT1b, which is involved in telomere capping. Here we performed the first quantitative DNA binding study of this plant-specific family of proteins. Interactions of full-length proteins AtTRB1 and AtTRB3 with telomeric DNA were analyzed by electrophoretic mobility-shift assay, fluorescence anisotropy and surface plasmo...
Source: BJ Plant - December 22, 2008 Category: Biochemistry Authors: C Hofr, P Šultesová, M Zimmermann, I Mozgová, P Procházková Schrumpfová, M Wimmerová, J Fajkus Tags: BJ Plant Source Type: journals

Mapping of a copper binding site on the small CP12 chloroplastic protein, using top down mass spectrometry and site- directed mutagenesesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CP12 is a small chloroplastic protein involved in the Calvin cycle that was shown to bind copper, a metal ion involved in modulation of its transition from reduced to oxidized state. In order to describe CP12 copper binding properties, copper-IMAC experiments and site-directed mutagenesis based on computational modeling, were coupled to top-down mass spectrometry (ESI-MS and MSMS). Copper-IMAC experiments allowed the primary characterization of mutation effects upon copper binding. Top-down MSMS experiments carried out under non-denaturing conditions on wild-type and mutant CP12/Cu2+ complexes then allowed fragment ions sp...
Source: BJ Plant - December 22, 2008 Category: Biochemistry Authors: J Erales, B Gontero, J Whitelegge, F Halgand Tags: BJ Structure Source Type: journals

Effect of Arabidopsis COP10 ubiquitin E2 enhancement activity across E2 families and functional conservation among its canonical homologsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Arabidopsis thaliana COP10 is a ubiquitin-conjugating enzyme (E2) variant (UEV) which is required for repression of seedling photomorphogenesis in darkness. COP10 forms a complex (the CDD complex) with DET1 and DDB1a in vivo and can enhance the activity of ubiquitin-conjugating enzyme (E2) in vitro. To investigate whether COP10 might act as a general regulator of ubiquitin-conjugating enzymes, we tested the specificity of COP10 E2 enhancement activity across E2 families of Arabidopsis. We found that COP10 is capable of enhancing members from four E2 subgroups significantly, while having a milder effect on another. Surprisi...
Source: BJ Plant - December 5, 2008 Category: Biochemistry Authors: O Lau, X Deng Tags: BJ Plant Source Type: journals

Characterization of the phenylurea hydrolases A and B: founding members of a novel amidohydrolase subgroupEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mycobacterium brisbanense strain JK1, a bacterium capable of degrading the herbicide diuron, was isolated from herbicide exposed soil. A gene/enzyme system with diuron-hydrolase activity was isolated from this strain and named phenylurea hydrolase B (puhB/PuhB) because of its close similarity to the previously characterised phenylurea hydrolase A (puhA/PuhA). Both phenylurea hydrolases (PUHs) were heterologously expressed, purified and characterised. The PUHs were found to oligomerise as hexamers in solution, with each monomer containing a mononuclear Zn2+ active site. Sequence analysis shows that these enzymes belong to t...
Source: BJ Plant - November 11, 2008 Category: Biochemistry Authors: J L Khurana, C J Jackson, C Scott, G Pandey, I Horne, R J Russell, A John Herlt, C J Easton, J G Oakeshott Tags: BJ Cell Source Type: journals

Structural analysis of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase in complex with xylotetraose reveals a different binding mechanism compared to other members of the same familyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Arabinoxylan arabinofuranohydrolases (AXH) are α-L-arabinofuranosidases that specifically hydrolyze the glycosidic bond between arabinofuranosyl substituents and xylopyranosyl backbone residues from arabinoxylan. Bacillus subtilis was recently shown to produce an AXH that cleaves arabinose units from O-2- or O-3-monosubstituted xylose residues: BsAXH-m2,3. Crystallographic analysis reveals a two domain structure for this enzyme: a catalytic domain displaying a 5-bladed β-propeller fold characteristic to glycoside hydrolase family (GH) 43 and a carbohydrate binding module (CBM) with a β-sandwich fold be...
Source: BJ Plant - November 4, 2008 Category: Biochemistry Authors: E Vandermarliere, T M Bourgois, M D. Winn, S Van Campenhout, G Volckaert, J A. Delcour, S V. Strelkov, A Rabijns, C M. Courtin Tags: BJ Structure Source Type: journals

Comparative analysis of CAX2-like cation transporters indicates functional and regulatory diversityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Internal compartmentalisation of metals is an important metal tolerance mechanism in many organisms. In plants and fungi, sequestration into the vacuole is a major detoxification mechanism for metals. Cation transport into the vacuole can be mediated by cation/H+ exchanger (CAX) transporters. The Arabidopsis thaliana AtCAX2 transporter was previously shown to transport Ca2+, Cd2+ and Mn2+. To assess the conservation of functional and regulatory characteristics of CAX2-like transporters in higher plants, we have characterized AtCAX2 orthologues from Arabidopsis (AtCAX5), tomato (LeCAX2) and barley (HvCAX2). Substrate specif...
Source: BJ Plant - October 24, 2008 Category: Biochemistry Authors: C Edmond, T Shigaki, S Ewert, M D Nelson, J M Connorton, V Chalova, Z Noordally, J K. Pittman Tags: BJ Plant Source Type: journals

Activation of a nuclear localized-SIPK in tobacco cells challenged by cryptogein, an elicitor of plant defence reactionsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
When a plant cell is challenged by a well-defined stimulus, complex signal transduction pathways are activated to promote the modulation of specific sets of genes and in fine to develop adaptive responses. In this context, protein phosphorylation plays a fundamental role through the activation of multiple protein kinase families. While the involvement of protein kinases at the plasma membrane and cytosolic levels are now well documented, their nuclear counterparts are still poorly investigated. In the field of plant defense reactions, no known study has yet reported the activation of a nuclear protein kinase and / or its n...
Source: BJ Plant - October 16, 2008 Category: Biochemistry Authors: J Dahan, C Pichereaux, M Rossignol, S Blanc, D Wendehenne, A Pugin, S Bourque Tags: BJ Plant Source Type: journals

Arabidopsis thaliana GLX2-1 contains a dinuclear metal binding site but is not a glyoxalase 2Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In an effort to probe the structure and function of a predicted mitochondrial glyoxalase 2 (GLX2-1) from Arabidopsis thaliana, GLX2-1 was cloned, over-expressed, purified, and characterized using metal analyses, kinetics, and UV-Vis, EPR, and 1H NMR spectroscopies. The purified enzyme was purple and contained substoichiometric amounts of iron and zinc; however, metal binding studies reveal that GLX2-1 can bind nearly 2 equivalents of either iron or zinc and that the most stable analog of GLX2-1 is the iron-containing form. UV-Vis spectra of the purified enzyme suggest the presence of Fe(II) in the protein, but the Fe(II) c...
Source: BJ Plant - September 9, 2008 Category: Biochemistry Authors: P Limphong, M W. Crowder, B Bennett, C A. Makaroff Tags: BJ Structure Source Type: journals

Identification of new protein substrates for the chloroplast ATP-dependent Clp protease supports its constitutive role in ArabidopsisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we have examined in detail the only viable knockout mutant to date of one of these subunits in Arabidopsis thaliana, ClpR1. Loss of ClpR1 caused a slow-growth phenotype, with chlorotic leaves during early development that later partially recovered upon maturity. Analysis of the Clp proteolytic core in the clpR1 mutant (clpR1-1) revealed ca. 10% of the wild type levels remaining, likely due to a relative increase in the closely related ClpR3 protein and its partial substitution of ClpR1 in the core complex. A proteomic approach using an in organello proteolytic assay revealed 19 new potential substrates for t...
Source: BJ Plant - August 29, 2008 Category: Biochemistry Authors: T M Stanne, L LE Sjögren, S Koussevitzky, A K Clarke Tags: BJ Plant Source Type: journals

Salt-stress-induced association of phosphatidylinositol-4,5-bisphosphate with clathrin-coated vesicles in plantsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Plants exposed to hyperosmotic stress undergo changes in membrane dynamics and lipid composition to maintain cellular integrity and avoid membrane leakage. Various plant species respond to hyperosmotic stress with transient increases in phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2), however, the physiological role of such increases is unresolved. Here, the spatio-temporal dynamics of stress-induced changes in phosphoinositides (PIs) were analyzed in subcellular fractions of Arabidopsis leaves to delineate possible physiological roles. Unlabeled lipids were separated by thin-layer-chromatography and quantified accor...
Source: BJ Plant - August 22, 2008 Category: Biochemistry Authors: S König, T Ischebeck, J Lerche, I Stenzel, I Heilmann Tags: BJ Plant Source Type: journals

Structure-function analysis of plant aquaporin AtPIP2;1 gating by divalent cations and protonsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Water channel proteins (aquaporins) of the Plasma membrane Intrinsic Protein(PIP) subfamily provide means for fine and quick adjustments of the plant water status. A molecular model for gating of PIPs by cytosolic protons (H+) and divalent cations was derived from the atomic structure of spinach SoPIP2;1 in an open- and a closed-pore conformation. Here, we produced in Pichia pastoris the Arabidopsis AtPIP2;1 homolog, either wild-type (WT) or with mutations at residues supposedly involved in gating. Stopped-flow spectrophotometric measurements showed that, upon reconstitution in proteoliposomes, all forms function as water ...
Source: BJ Plant - July 21, 2008 Category: Biochemistry Authors: L Verdoucq, A Grondin, C Maurel Tags: BJ Plant Source Type: journals

Carotenoid oxygenases involved in plant branching catalyze a highly specific, conserved apocarotenoid cleavage reactionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recent studies with the high-tillering mutants in Oryza sativa, the more axillary growth (max) mutants in Arabidopsis thaliana and the ramosus (rms) mutants in Pisum sativum have indicated the presence of a novel plant hormone that inhibits branching in an auxin-dependent manner. The synthesis of this inhibitor is initiated by the two carotenoid cleaving oxygenases (CCDs) OsCCD7/OsCCD8b, MAX3/MAX4 and RMS5/1 in rice, Arabidopsis and pea, respectively. MAX3 and MAX4 are thought to catalyze the successive cleavage of a carotenoid substrate yielding an apocarotenoid that, possibly after further modification, inhibits the outg...
Source: BJ Plant - July 18, 2008 Category: Biochemistry Authors: A Alder, I Holdermann, P Beyer, S Al-Babili Tags: BJ Plant Source Type: journals

A novel protein phosphatase indirectly regulates phytochrome interacting factor 3 via phytochromeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Light signal transduction in plants involves an intricate series of pathways which is finely regulated by interactions between specific signaling proteins, as well as by protein modifications such as phosphorylation and ubiquitination. The identification of novel phytochrome-interacting proteins and the precise signaling mechanisms that they mediate is still ongoing. In our current study, we show that the newly identified putative phytochrome-associated protein, PAPP2C (phytochrome-associated protein phosphatase type 2C), interacts in the nucleus with phytochrome A (phyA) and B (phyB), both in vitro and in vivo. Moreover, ...
Source: BJ Plant - June 20, 2008 Category: Biochemistry Authors: B Phee, J Kim, D Shin, J Yoo, K Park, Y Han, Y Kwon, M Cho, J Jeon, S Bhoo, T Hahn Tags: BJ Plant Source Type: journals

Evolving improved Synechococcus Rubisco functional expression in Escherichia coliEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The photosynthetic CO2-fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) has long been a target for engineering kinetic improvements. Towards this goal we used a Rubisco dependent Escherichia coli (RDE) selection system to evolve Synechococcus PCC6301 Form I Rubisco under different selection pressures. In the fastest growing colonies the Rubisco large (L) subunit substitutions Ile-174-Val, Gln-212-Leu, Met-262-Thr, Phe-345-Leu or Phe-345-Ile were repeatedly selected and shown to increase functional Rubisco expression 4 to 7-fold in the RDE and 5 to 17-fold when expressed in XL1-Blue E. coli. Introduci...
Source: BJ Plant - May 19, 2008 Category: Biochemistry Authors: O Mueller-Cajar, S Whitney Tags: BJ Plant Source Type: journals

Plant plasma membrane water channels conduct the signaling molecule H2O2Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hydrogen peroxide (H2O2) is a relatively long-lived reactive oxygen species that signals between cells and organisms. H2O2 signaling in plants is essential for response to stress, defense against pathogens, and the regulation of programmed cell death. Although H2O2 diffusion across membranes is often considered as a passive property of lipid bilayers, native membranes represent significant barriers for hydrogen peroxide. We addressed the question of whether channels might facilitate H2O2 transport across plasma membranes. The expression of several plant plasma membrane aquaporins in yeast, including PIP2;1 from Arabidopsis...
Source: BJ Plant - May 8, 2008 Category: Biochemistry Authors: M Dynowski, G Schaaf, D Loque, O Moran, U Ludewig Tags: BJ Signal Source Type: journals

Molecular control of the glucan-synthase-like protein NaGSL1 and callose synthesis during growth of Nicotiana alata pollen tubesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The protein NaGSL1 (Nicotiana alata glucan synthase-like 1) is implicated in the synthesis of callose, the 1,3-β-glucan that is the major polysaccharide in the walls of N. alata pollen tubes. Here we examine the production, intracellular location and post-translational processing of NaGSL1, and relate each of these to the regulation of pollen-tube callose synthase (CalS). The 220-kDa NaGSL1 polypeptide is produced after pollen-tube germination and accumulates during pollen-tube growth, as does CalS. A combination of membrane fractionation and immuno-electron microscopy revealed that NaGSL1 was present predominantly ...
Source: BJ Plant - May 7, 2008 Category: Biochemistry Authors: L Brownfield, S Wilson, E Newbigin, A Bacic, S Read Tags: BJ Plant Source Type: journals

Insights into substrate specificity of plant peptide deformylase, an essential enzyme with potential for the development of novel biotechnology applications in agricultureEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The crystal structure of Arabidopsis thaliana peptide deformylase (AtPDF1B; EC 3.5.1.88), a plant specific deformylase, has been determined at a resolution of 2.4 Å. The overall fold of AtPDF1B is similar to other peptide deformylases that have been reported. Evidence from the crystal structure and gel filtration chromatography indicates that AtPDF1B exists as a symmetric dimer. PDF1B is essential in plants and has preferred substrate specificity towards the photosystem II D1 polypeptide. Comparative analysis of AtPDF1B, AtPDF1A, and the type 1B deformylase from Escherichia coli, identifies a number of differences i...
Source: BJ Plant - April 16, 2008 Category: Biochemistry Authors: L M.A. Dirk, J J. Schmidt, Y Cai, J C. Barnes, K M. Hanger, N R. Nayak, M A. Williams, R B. Grossman, R L Houtz, D Rodgers Tags: BJ Plant Source Type: journals

Biochemical function of typical and variant Arabidopsis thaliana U-box E3 ubiquitin-protein ligasesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion, both typical and atypical Arabidopsis U-box proteins were active E3s. The overlap in the E3/E2 selectivity suggests that in vivo specificity is not determined only by the E3/E2 interactions but also by other parameters, e.g. co-existence or interactions with additional domains. The biochemical functions of AtPUB49 suggest that the protein can be involved in folding or degradation of protein substrates. Similar functions can also be retained within a protein complex with separate chaperone and U-box proteins. (Source: BJ Plant)
Source: BJ Plant - April 7, 2008 Category: Biochemistry Authors: J Wiborg, C O'Shea, K Skriver Tags: BJ Plant Source Type: journals