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'Sulfo-click' for ligation as well as for site-specific conjugation with peptides, fluorophores, and metal chelatorsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The 'sulfo-click' reaction, which is a chemoselective amidation reaction involving the reaction of an aminoethane sulfonyl azide with a thio acid, encompasses a new approach for ligation and conjugation. Detailed protocols are provided for decorating biologically active peptides or dendrimers with biophysical tags, fluorescent probes, metal chelators, and small peptides by using this reaction as a novel, metal-free 'sulfo-click' approach. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. (Source: Journal of Peptide Science)
Source: Journal of Peptide Science - November 20, 2009 Category: Biochemistry Authors: Dirk T. S. Rijkers, Remco Merkx, Cheng-Bin Yim, Arwin J. Brouwer, Rob M. J. Liskamp Source Type: journals

Novel analogues of arginine vasopressin containing [alpha]-2-indanylglycine enantiomers in position 2Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Continuing our efforts to obtain potent and selective analogues of AVP we synthesized and pharmacologically evaluated ten new compounds modified at position 2 with [alpha]-2-indanylglycine or its D-enantiomer (Igl or D-Igl, respectively). All the peptides were tested for pressor, antidiuretic, and in vitro uterotonic activities. We also determined the binding affinity of these compounds to human OT receptor. The Igl2 substitution resulted in a significant change of the pharmacological profile of the peptides. The new analogues were moderate or potent OT antagonists (pA2 values ranging from 7.19 to 7.98) and practically did...
Source: Journal of Peptide Science - November 18, 2009 Category: Biochemistry Authors: Anna Kwiatkowska, Ma[lstrok]gorzta [Sacute]leszy[nacute]ska, Izabela Derdowska, Adam Prahl, Dariusz Sobolewski, Lenka Borovi[ccaron]ková, Ji[rcaron]ina Slaninová, Bernard Lammek Source Type: journals

On the use of N-dicyclopropylmethyl aspartyl-glycine synthone for backbone amide protectionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
To prevent aspartimide formation and related side products in Asp-Xaa, particularly Asp-Gly-containing peptides, usually the 2-hydroxy-4-methoxybenzyl (Hmb) backbone amide protection is applied for peptide synthesis according to the Fmoc-protocols. In the present study, the usefulness of the recently proposed acid-labile dicyclopropylmethyl (Dcpm) protectant was analyzed. Despite the significant steric hindrance of this bulky group, N-terminal H-(Dcpm)Gly-peptides are quantitatively acylated by potent acylating agents, and alternatively the dipeptide Fmoc-Asp(OtBu)-(Dcpm)Gly-OH derivative can be used as a building block. I...
Source: Journal of Peptide Science - November 18, 2009 Category: Biochemistry Authors: René Röder, Petra Henklein, Hardy Weißhoff, Clemens Mügge, Michael Pätzel, Ulrich Schubert, Louis A. Carpino, Peter Henklein Source Type: journals

Structure-antigenicity of the V3 region of SIVmac envelope glycoproteinEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of this study was to analyze the immunogenicity and antigenicity of the V3 domain (Cys313-Cys346) of the external envelope glycoprotein gp125 of SIVmac251. The corresponding peptide was synthesized and characterized as linear and cyclic peptides. Our results showed that this region, as for HIV-1, contained an immunodominant epitope. The antigenicity was similar for the linear and cyclic peptides when tested against a panel of 15 sera from SIV infected macaques. Similarly, both peptide structures presented similar immunogenicity as shown by the characterization of the anti-peptide antibodies produced in rabbit...
Source: Journal of Peptide Science - November 12, 2009 Category: Biochemistry Authors: Fabrice Gaston, Tahar Babas, Faouzi Lakhdar-Ghazal, Elmostafa Bahraoui Source Type: journals

Identification of a novel antitumor peptide based on the screening of an Ala-library derived from the LALF32-51 regionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Novel therapeutic peptides are increasingly making their way into clinical application. The cationic and amphipathic properties of certain peptides allow them to cross biological membranes in a non-disruptive way without apparent toxicity increasing drug bioavailability. By modifying the primary structure of the Limulus-derived LALF32-51 peptide we designed a novel peptide, L-2, with antineoplastic effect and cell-penetrating capacity. Interestingly, L-2 induced cellular cytotoxicity in a variety of tumor cell lines and systemic injection into immunocompetent and nude mice bearing established solid tumor, resulted in subst...
Source: Journal of Peptide Science - November 11, 2009 Category: Biochemistry Authors: Maribel G. Vallespi, Julio R. Fernandez, Isis Torrens, Isbel Garcia, Hilda Garay, Osmani Mendoza, Milaid Granadillo, Viviana Falcon, Boris Acevedo, Raimundo Ubieta, Gerardo E. Guillen, Osvaldo Reyes Source Type: journals

Microwave-assisted TFA cleavage of peptides from Merrifield resinEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Microwave-assisted (MW) reactions are of special interest to the chemical community due to faster reaction times, cleaner reactions and higher product yields. The adaptation of MW to solid phase peptide synthesis resulted in spectacular syntheses of difficult peptides. In the case of Merrifield support, used frequently in synthesis of special peptides, the conditions used in product cleavage are not compatible with off-resin monitoring of the reaction progress. The application of MW irradiation in product removal from Merrifield resin using trifluoroacetic acid (TFA) was investigated using model tetrapeptides and the effec...
Source: Journal of Peptide Science - November 11, 2009 Category: Biochemistry Authors: Alicja Kluczyk, Magdalena Rudowska, Piotr Stefanowicz, Zbigniew Szewczuk Source Type: journals

Colostrum and bioactive, colostral peptides differentially modulate the innate immune response of intestinal epithelial cellsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Characterization and identification of peptides with bioactivity from food have received considerable interest recently since such bioactive components must be adequately documented if they are part of functional food claims. We have characterized peptides from colostrum or those generated by a simulated gastrointestinal digest (GI) and tested them for bioactivity using murine intestinal (mICc12) cells and compared with bioactivity of intact colostrum. The peptides were recovered in the permeate after dialysis. The presence of peptides in the permeate was confirmed by C18 RP-HPLC, determination of free amino termini and MA...
Source: Journal of Peptide Science - November 10, 2009 Category: Biochemistry Authors: Ann Louise Worsøe Jørgensen, Helle Risdahl Juul-Madsen, Jan Stagsted Source Type: journals

Folding in Solution of the C - Catalytic Protein Fragment of Angiotensin Converting Enzyme Sotirios-Spyridon M. Vamvakas, Leondios Leondiadis, George Pairas, Evy Manessi-Zoupa, Georgios A. Spyroulias and Paul CordopatisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The original article to which this Erratum refers was published in Journal of Peptide Science, 2009: 15: Pages 504-510 (Source: Journal of Peptide Science)
Source: Journal of Peptide Science - November 3, 2009 Category: Biochemistry Tags: Errata Source Type: journals

First selective agonist of the neuropeptide Y1-receptor with reduced sizeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Selective NPY analogues are potent tools for tumour targeting. Their Y1-receptors are significantly over-expressed in human breast tumours, whereas normal breast tissue only expresses Y2-receptors. The endogenous peptide consists of 36 amino acids, whereas smaller peptides are preferred because of better labelling efficiencies. As Y1-receptor agonists enhance the tumour to background ratio compared to Y1-receptor antagonists, we were interested in the development of Y1-receptor selective agonists. We designed 19 peptides containing the C-terminus of NPY (28-36) with several modifications. By using competition receptor bind...
Source: Journal of Peptide Science - November 3, 2009 Category: Biochemistry Authors: Denise Zwanziger, Ilka Böhme, Diana Lindner, Annette G. Beck-Sickinger Tags: Research Articles Source Type: journals

Peptide T exhibits a well-defined structure in fluorinated solvent at low temperatureEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The structure of Peptide T was determined by solution NMR spectroscopy, under strong structure-inducing conditions: 40% hexafluoro-2-propanol aqueous solution at 5 °C. Under these conditions it was possible to detect medium-range NOEs for the first time for this peptide. This allowed a much better-defined structure to be determined for Peptide T in comparison with earlier NMR and computational studies. Peptide structures consistent with the experimental restraints were generated using a restrained MD simulation with a full empirical force field. Residues 4-8 of Peptide T take on a well-defined structure with a heavy atom ...
Source: Journal of Peptide Science - October 29, 2009 Category: Biochemistry Authors: Tran-Chin Yang, Jennifer Rendell, Wayne Gulliver, Valerie Booth Source Type: journals

One-pot protection and activation of amino acids using pentafluorophenyl carbonatesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Protection of the amino group and activation of the carboxylic acid groups are the most important steps associated with any peptide synthesis protocol; hence, a one-pot process to achieve these is highly desirable. A possible strategy is to use pentafluorophenyl carbonates to simultaneously protect the amino group as a carbamate derivative and activate the carboxylic acid group as a pentafluorophenyl ester. A detailed study is carried out to understand the scope and limitations of this method using five different pentaflurophenyl carbonates. The efficiency of these one-pot reactions depends largely on the nature of the pen...
Source: Journal of Peptide Science - October 23, 2009 Category: Biochemistry Authors: Ramesh Ramapanicker, Nasir Baig Rashid Baig, Kavita De, Srinivasan Chandrasekaran Source Type: journals

Minimal motif peptide structure of metzincin clan zinc peptidases in micellesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we focused our attention on the zinc-binding motif of the metzincin clan family, HEXXHXXGXXH; this family contains the general zinc-binding sequence His-Glu-Xaa-Xaa-His (HEXXH) and the extended GXXH region. We adopted the motif sequence of stromelysin-1 and investigated the folding properties of the Trp-labeled peptides WAHEIAHSLGLFHA (STR-W1), AWHEIAHSLGLFHA (STR-W2), AHEIAHSLGWFHA (STR-W11), and AHEIAHSLGLFHWA (STR-W14) in the presence and absence of zinc ions in hydrophobic micellar environments by circular dichroism (CD) measurements. We accessed successful incorporation of these zinc peptides into micel...
Source: Journal of Peptide Science - October 14, 2009 Category: Biochemistry Authors: Akira Onoda, Takako Suzuki, Hiroaki Ishizuka, Rumiko Sugiyama, Shinya Ariyasu, Takeshi Yamamura Source Type: journals

The cytotoxic effects of the anti-bacterial peptides on leukocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In conclusion we show here that antimicrobial peptides are not cytotoxic for the resting eukaryotic cells but can be cytotoxic on activated immune cells through distinct mechanisms of cell death. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. (Source: Journal of Peptide Science)
Source: Journal of Peptide Science - October 13, 2009 Category: Biochemistry Authors: Sergiu-Bogdan Catrina, Essam Refai, Mats Andersson Source Type: journals

Working outside the protein-synthesis rules: insights into non-ribosomal peptide synthesisEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Non-ribosomally synthesized microbial peptides show remarkable structural diversity and constitute a widespread class of the most potent antibiotics and other important pharmaceuticals that range from penicillin to the immunosuppressant cyclosporine. They are assembled independent of the ribosome in a nucleic acids-independent way by a group of multimodular megaenzymes called non-ribosomal peptide synthetases. These biosynthetic machineries rely not only on the 20 canonical amino acids, but also use several different building blocks, including D-configured- and [beta]-amino acids, methylated, glycosylated and phosphorylate...
Source: Journal of Peptide Science - October 12, 2009 Category: Biochemistry Authors: Mohamed A. Marahiel Source Type: journals

Microwave-assisted solid-phase peptide synthesis at 60 °C: alternative conditions with low enantiomerizationEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, aimed to further examine enantiomerization under such condition and study the applicability of our protocols to microwave-SPPS, peptides containing L-Ser, L-His, L-Cys and/or L-Met were manually synthesized traditionally, at 60 °C using conventional heating and at 60 °C using microwave heating. Detailed assessment of all crude peptides (in their intact and/or fully hydrolyzed forms) revealed that, except for the microwave-assisted coupling of L-Cys, all other reactions occurred with low levels of amino acid enantiomerization ( (Source: Journal of Peptide Science)
Source: Journal of Peptide Science - October 12, 2009 Category: Biochemistry Authors: Carina Loffredo, Nilson A. Assunção, Juergen Gerhardt, M. Terêsa Machini Miranda Source Type: journals

Convergent solid-phase and solution approaches in the synthesis of the cysteine-rich Mdm2 RING finger domainEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The RING finger domain of the Mdm2, located at the C-terminus of the protein, is necessary for regulation of p53, a tumor suppressor protein. The 48-residues long Mdm2 peptide is an important target for studying its interaction with small anticancer drug candidates. For the chemical synthesis of the Mdm2 RING finger domain, the fragment condensation on solid-phase and the fragment condensation in solution were studied. The latter method was performed using either protected or free peptides at the C-terminus as the amino component. Best results were achieved using solution condensation where the N-component was applied with...
Source: Journal of Peptide Science - October 12, 2009 Category: Biochemistry Authors: Zoe Vasileiou, Kostas Barlos, Dimitrios Gatos Source Type: journals

Ghrelin - a novel generation of anti-obesity drug: design, pharmacomodulation and biological activity of ghrelin analoguesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ghrelin is a unique bioactive peptide with respect to both the structure and its biological function. This 28-amino acid peptide is modified with an n-octanoyl group at serine-3, and accordingly is the only lipidated biologically active peptide hormone known so far. Ghrelin binds to the so-called ghrelin or GHS receptor, a member of the class A of G-protein coupled receptors, which leads to Ca2+ release intracellularly due to the activation of the Gq-system. Interestingly, the ghrelin receptor shows a significant constitutive activity which means that in addition to agonists and antagonists, inverse agonists play an import...
Source: Journal of Peptide Science - September 29, 2009 Category: Biochemistry Authors: Constance Chollet, Karolin Meyer, Annette G. Beck-Sickinger Source Type: journals

Efficient method of circumventing insolubility problems with fully protected peptide carboxylates via in situ direct thioesterification reactionsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A straightforward and convenient protocol is presented for the direct thioesterification of fully protected peptide C-terminal carboxylates synthesized by Fmoc strategy. This methodology specifically serves to overcome the frequent insolubility problem of these fully protected carboxolate isolates during the thioesterification process by carrying out the reaction as an in situ procedure on the freshly cleaved 1% TFA/DCM solution of carboxylate. The direct thioesterification of a number of insolubility prone peptide systems is explored and compared with some control systems for ease of conversion to the corresponding thioes...
Source: Journal of Peptide Science - September 28, 2009 Category: Biochemistry Authors: Stevenson Flemer Jr Source Type: journals

Receptor assay guided structure-activity studies of helicokinin insect neuropeptides and peptidomimetic analoguesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Neuropeptides control numerous physiological processes in insects. The regulation of water balance is a crucial aspect of homeostasis in terrestrial insects and has been shown to be under endocrine control, primarily by corticotrophin releasing factor (CRF)-related peptides and kinins. For helicokinin I, a diuretic neuropeptide from the economically important insect pest Heliothis virescens, detailed structure-activity relationships have been established based on truncated structures, diverse amino acid scans and peptidomimetic analogues. The activities of selected compounds on functional expressed helicokinin receptors ar...
Source: Journal of Peptide Science - September 28, 2009 Category: Biochemistry Authors: Jürgen Scherkenbeck, Horst-Peter Antonicek, Kathrin Vogelsang, Tino Zdobinsky, Karin Brücher, Denise Rehländer, Heru Chen Source Type: journals

The pH sensitivity of histidine-contain- ing lytic peptidesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, histidine-containing peptides were constructed by selectively replacing the corresponded lysine residues in a lytic peptide LL-1 with histidines. Interestingly, all resulting peptides demonstrated pH-dependent activities. The cell lysis activities of these peptides could be increased up to four times as the solution pHs dropped from pH = 7.4 to pH = 5.5. The pH sensitivity of a histidine-containing peptide was determined by histidine substitution numbers. Peptide derivatives with more histidines were associated with increased pH sensitivity. Results showed that not the secondary structures but pH-affected ce...
Source: Journal of Peptide Science - September 28, 2009 Category: Biochemistry Authors: Zhigang Tu, Albert Young, Christopher Murphy, Jun F. Liang Source Type: journals

ObituaryEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
No Abstract. (Source: Journal of Peptide Science)
Source: Journal of Peptide Science - September 28, 2009 Category: Biochemistry Authors: Roger M. Freidinger, Daniel F. Veber Source Type: journals

Synthesis and receptor binding of opioid peptide analogues containing [beta]3-homo-amino acidsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
[beta]-Amino acids containing hybrid peptides and [beta]-peptides show great potential as peptidomimetics. In this paper we describe the synthesis and affinity toward the µ- and [delta]-opioid receptors of [beta]-peptides, analogues of Leu-enkephalin, deltorphin I, dermorphin and [alpha],[beta]-hybrides, analogues of deltorphin I. Substitution of [alpha]-amino acid residues with [beta]3-homo-amino acid residues, in general resulted in decrease of affinity to opioid receptors. However, the incorporation [beta]3h-D-Ala in position 2 or [beta]3hPhe in position 3 of deltorphin I resulted in potent and selective ligand for [de...
Source: Journal of Peptide Science - September 28, 2009 Category: Biochemistry Authors: Dominika Wilczy[nacute]ska, Piotr Kosson, Maria Kwasiborska, Andrzej Ejchart, Aleksandra Olma Source Type: journals

Local formation of angiotensin peptides with paracrine activity by adipocytesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A local paracrine angiotensin (ANG) system influences the insulin sensitivity and cell differentiation of adipose tissue. The limited view of a merely systemic renin-angiotensin-aldosterone-system with ANG II (1-8) as the main mediator of ANG-related effects may oversimplify the situation. The aim was to analyze the degradation of ANG by using capillary electrophoresis (CE) techniques. The supernatant of cultured 3T3-L1 adipocytes was used directly, and some data on degraded peptides were combined with a biological effect. The formation of several peptides such as ANG II (1-8), - III (2-8), - IV (3-8), and ANG (1-7) as deg...
Source: Journal of Peptide Science - September 28, 2009 Category: Biochemistry Authors: Felix Weiland, Eugen J. Verspohl Source Type: journals

The inherent flexibility of peptides and protein fragments quantitized by CD in conjunction with CCA+Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
ECD spectroscopy is traditionally used for rapid, non-atomic level structure analysis of natural products such as peptides and proteins. Unlike globular proteins, peptides less frequently adopt a single 3D-fold in a time average manner. Moreover, they exhibit an ensemble of conformers composed of a multitude of substantially different structures. In principle, both ECD- and vibrational circular dichroism (VCD)-spectroscopy are sensitive enough to pick up structural information on these dynamic ensembles. However, the interpretation of the raw spectral data of these highly dynamic molecular systems can be cumbersome. The he...
Source: Journal of Peptide Science - September 18, 2009 Category: Biochemistry Authors: Imre Jákli, András Perczel Source Type: journals

Quality specifications for peptide drugs: a regulatory-pharmaceutical approachEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Peptide drugs, as all types of pharmaceuticals, require adequate specifications (i.e. quality attributes, procedures and acceptance criteria) as part of their quality assurance to ensure the safety and efficacy of drug substances (i.e. active pharmaceutical ingredients) and drug products (i.e. finished pharmaceutical dosage forms). Compendial monographs are updated regularly to keep up with the most recent advances in peptide synthesis (e.g. reduced by-products) and analytical technology. Nevertheless, currently applied pharmacopoeial peptide specifications are barely harmonized yet (e.g. large differences between the Euro...
Source: Journal of Peptide Science - September 11, 2009 Category: Biochemistry Authors: Valentijn Vergote, Christian Burvenich, Christophe Van de Wiele, Bart De Spiegeleer Source Type: journals

Incorporation of N-amidino-pyroglutamic acid into peptides using intramolecular cyclization of [alpha]-guanidinoglutaric acidEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
N-terminal modification of peptides by unnatural amino acids significantly affects their enzymatic stability, conformational properties and biological activity. Application of N-amidino-amino acids, positively charged under physiological conditions, can change peptide conformation and its affinity to the corresponding receptor. In this article, we describe synthesis of short peptides, containing a new building block - N-amidino-pyroglutamic acid. Although direct guanidinylation of pyroglutamic acid and oxidation of N-amidino-proline using RuO4 did not produce positive results, N-amidino-Glp-Phe-OH was synthesized on Wang p...
Source: Journal of Peptide Science - September 8, 2009 Category: Biochemistry Authors: Sergey Burov, Yulia Moskalenko, Marina Dorosh, Zoya Shkarubskaya, Evgeny Panarin Source Type: journals

Modifying the conserved C-terminal tyrosine of the peptide hormone PYY3-36 to improve Y2 receptor selectivityEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The Y2 selective PYY derived peptide PYY3-36 was recently shown to play a role in appetite regulation. Novel PYY3-36 analogs with high selectivity for the Y2 receptor could be potential drug candidates for the treatment of obesity. The C-terminal pentapeptide segment of PYY3-36 is believed to bind to the Y receptors. Tyr-36 is highly conserved across species and only few successful modifications of Tyr-36 have been documented. PYY3-36 analogs were prepared using solid-phase peptide chemistry and tested for binding to the Y1, Y2 and Y4 receptor subtypes by radioligand displacement assay. The Y2 receptor agonists with the be...
Source: Journal of Peptide Science - September 7, 2009 Category: Biochemistry Authors: Søren L. Pedersen, Birgitte Holst, Niels Vrang, Knud J. Jensen Source Type: journals

Synthesis of peptide thioesters via an N-S acyl shift reaction under mild acidic conditions on an N-4,5-dimethoxy-2-mercaptobenzyl auxiliary groupEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An efficient method of peptide thioester synthesis is described. The reaction is based on an N-4,5-dimethoxy-2-mercaptobenzyl (Dmmb) auxiliary-assisted N-S acyl shift reaction after assembling a peptide chain by Fmoc-solid phase peptide synthesis. The Dmmb-assisted N-S acyl shift reaction proceeded efficiently under mildly acidic conditions, and the peptide thioester was obtained by treating the resulting S-peptide with sodium 2-mercaptoethanesulfonate. No detectable epimerization of the amino acid residue adjacent to the thioester moiety in the case of Leu was found. The reactions were also amenable to the on-resin prepar...
Source: Journal of Peptide Science - September 4, 2009 Category: Biochemistry Authors: Ken'ichiroh Nakamura, Tomoki Kanao, Tomoya Uesugi, Toshiaki Hara, Takeshi Sato, Toru Kawakami, Saburo Aimoto Source Type: journals

Switching between low and high affinity for the Syk tandem SH2 domain by irradiation of azobenzene containing ITAM peptidomimeticsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, photoswitchable ITAM peptidomimetics containing an azobenzene moiety were synthesized. Irradiation of these constructs changes the distance between the two SH2 binding epitopes and therefore, they may be used as photoswitches. The affinity of the cis- and trans-isomer for tSH2 was assayed with SPR. The ITAM peptidomimetic with the smallest linker displayed the largest difference in affinity between the two isomers (at least 100-fold), and the affinity of the cis-isomer was comparable to monovalent binding. The ITAM mimics with larger photoswitchable linkers displayed modest differences. These results indicat...
Source: Journal of Peptide Science - August 27, 2009 Category: Biochemistry Authors: Joeri Kuil, Loek T.M. van Wandelen, Nico J. de Mol, Rob M.J. Liskamp Source Type: journals

The use of post-translationally modified peptides for detection of biomarkers of immune-mediated diseasesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Biomarkers are decision-making tools at the basis of clinical diagnostics and essential for guiding therapeutic treatments. In this context, autoimmune diseases represent a class of disorders that need early diagnosis and steady monitoring. These diseases are usually associated with humoral or cell-mediated immune reactions against one or more of the body's own constituents. Autoantibodies fluctuating in biological fluids can be used as disease biomarkers and they can be, thus, detected by diagnostic immunoassays using native autoantigens. However, it is now accepted that post-translational modifications may affect the imm...
Source: Journal of Peptide Science - August 26, 2009 Category: Biochemistry Authors: Anna Maria Papini Source Type: journals

Morphology of self-assembled structures formed by short peptides from the amyloidogenic protein tau depends on the solvent in which the peptides are dissolvedEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The aggregation behavior of peptides Ac-VQIVYK-amide (AcPHF6) and Ac-QIVYK-amide (AcPHF5) from the amyloidogenic protein tau was examined by atomic force microscopy (AFM) and fluorescence microscopy. Although AcPHF5 did not show enhancement of thioflavin T (ThT) fluorescence in aqueous buffer, distinct aggregates were discernible when peptide was dissolved in organic solvents such as methanol (MeOH), trifluoroethanol (TFE), and hexafluoroisopropanol (HFIP) dried on mica and examined by AFM. Self-association was evident even though the peptide did not have the propensity to form secondary structures in the organic solvents....
Source: Journal of Peptide Science - August 26, 2009 Category: Biochemistry Authors: Nitin Chaudhary, Shashi Singh, Ramakrishnan Nagaraj Source Type: journals

Preliminary studies on noncovalent hyperbranched polymers based on PNA and DNA building blocksEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this work, we report thermodynamic, kinetic, and microrheological studies relative to the formation of PNA- and PNA/DNA-based noncovalent polymeric systems, useful tools for biotechnological and bioengineering applications. We realized two kinds of systems: a PNA-based system formed by a self-assembling PNA tridendron, and a PNA/DNA hybrid system formed by a PNA tridendron and a DNA linker. The formation of a three-dimensional polymeric network, by means of specific Watson-Crick base pairing, was investigated by a detailed UV and CD spectroscopic study. Preliminary microrheology experiments were performed on both system...
Source: Journal of Peptide Science - August 18, 2009 Category: Biochemistry Authors: Maria Moccia, Domenica Musumeci, Giovanni N. Roviello, Sabato Fusco, Margherita Valente, Enrico M. Bucci, Roberto Sapio, Carlo Pedone, Paolo A. Netti Source Type: journals

Design of a bioactive cell-penetrating peptide: when a transduction domain does more than transduceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The discovery of cell-penetrating peptides (CPPs) has facilitated delivery of peptides into cells to affect cellular behavior. Previously, we were successful at developing a phosphopeptide mimetic of the small heat shock-like protein HSP20 . Building on this success we developed a cell-permeant peptide inhibitor of mitogen-activated protein kinase-activated protein kinase 2 (MK2). It is well documented that inhibition of MK2 may be beneficial for a myriad of human diseases including those involving inflammation and fibrosis. During the optimization of the activity and specificity of the MK2 inhibitor (MK2i) we closely exam...
Source: Journal of Peptide Science - August 17, 2009 Category: Biochemistry Authors: Brian Ward, Brandon L. Seal, Colleen M. Brophy, Alyssa Panitch Source Type: journals

Membrane association and selectivity of the antimicrobial peptide NK-2: a molecular dynamics simulation studyEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In an effort to better understand the initial mechanism of selectivity and membrane association of the synthetic antimicrobial peptide NK-2, we have applied molecular dynamics simulation techniques to elucidate the interaction of the peptide with the membrane interfaces. A homogeneous dipalmitoylphosphatidylglycerol (DPPG) and a homogeneous dipalmitoylphosphatidylethanolamine (DPPE) bilayers were taken as model systems for the cytoplasmic bacterial and human erythrocyte membranes, respectively. The results of our simulations on DPPG and DPPE model membranes in the gel phase show that the binding of the peptide, which is co...
Source: Journal of Peptide Science - August 17, 2009 Category: Biochemistry Authors: Jutarat Pimthon, Regine Willumeit, Andreas Lendlein, Dieter Hofmann Source Type: journals

Synthesis of protein kinase C[delta] C1b domain by native chemical ligation methodology and characterization of its folding and ligand bindingEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The C1b domain of protein kinase C[delta] (PKC[delta]), a potent receptor for ligands such as diacylglycerol and phorbol esters, was synthesized by utilizing native chemical ligation. With this synthetic strategy, the domain was efficiently constructed and shown to have high affinity ligand binding and correct folding. The C1b domain has been utilized for the development of novel ligands for the control of phosphorylation by PKC family members. This strategy will pave the way for the efficient construction of C1b domains modified with fluorescent dyes, biotin, etc. Copyright © 2009 European Peptide Society and John Wiley ...
Source: Journal of Peptide Science - August 11, 2009 Category: Biochemistry Authors: Nami Ohashi, Wataru Nomura, Mai Kato, Tetsuo Narumi, Nancy E. Lewin, Peter M. Blumberg, Hirokazu Tamamura Source Type: journals

Effect of Leucine and Lysine substitution on the antimicrobial activity and evaluation of the mechanism of the HPA3NT3 analog peptideEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, a HPA3NT3-analog (FKKLKKLFKKILKLK-NH2) peptide was designed. In this analog, two Trp residues (positions 12, 14) were replaced with Leu, and Arg and Asn (positions 3, 13) were replaced with Lys to investigate the role of amino acid substitution and increased cationicity on antimicrobial and hemolytic activities. In fungal and Gram-negative bacterial cells, HPA3NT3-analog activity was unchanged or slightly enhanced when compared to the HPA3NT3 peptide. In addition, a twofold decrease in activity against Gram-positive bacteria was observed. The HPA3NT3-analog also induced less hemolysis (4.2%) than the HPA3NT3...
Source: Journal of Peptide Science - July 29, 2009 Category: Biochemistry Authors: Ramamourthy Gopal, Seong-Cheol Park, Kyeoung-Ju Ha, Seung Joo Cho, Si Wouk Kim, Peter I. Song, Jae-Woon Nah, Yoonkyung Park, Kyung-Soo Hahm Source Type: journals

Synergistic antioxidative activities of hydroxycinnamoyl-peptidesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Antioxidants have become an important subject of study as an active ingredient for cosmetics and preservatives for food. We synthesized antioxidative peptide conjugates of hydroxycinnamic acids (HCAs) such as ferulic acid (FA), caffeic acid (CA), and sinapic acid (SA) by SPPS method. We measured their potential antioxidant properties by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging test and lipid autoxidation inhibition test. When the antioxidative peptides, such as glutathione analogue (GS(Bzl)H) and carnosine (CAR), were conjugated to HCAs, their antioxidative activities were enhanced significantly. CA-peptides...
Source: Journal of Peptide Science - July 28, 2009 Category: Biochemistry Authors: Seon-Yeong Kwak, Hyo-Suk Seo, Yoon-Sik Lee Source Type: journals

Solid-phase peptide synthesis using acetonitrile as a solvent in combination with PEG-based resinsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This manuscript shows that ACN can be an excellent choice for the coupling of hindered amino acids as illustrated by the coupling of Fmoc-amino acids on free amino acids anchored on a BAL synthesis. Furthermore, ACN can be a good alternative for solid-phase peptide synthesis in the absence of DMF (washings, removal of Fmoc, and coupling). Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd. (Source: Journal of Peptide Science)
Source: Journal of Peptide Science - July 23, 2009 Category: Biochemistry Authors: Gerardo A. Acosta, Montserrat del Fresno, Marta Paradis-Bas, Maria Rigau-DeLlobet, Simon Côté, Miriam Royo, Fernando Albericio Source Type: journals

Cell selectivity-membrane phospholipids relationship of the antimicrobial effects shown by pleurocidin enantiomeric peptidesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, confocal laser scanning microscopy indicates that the Ple enantiomers internalize into the cell surface. The present results also suggest that they could be characterized by a membrane-active mechanism. To further elucidate their selective membranolytic activities, we conducted a fluorescence analysis. A study with 1,6-diphenyl-1,3,5-hexatriene, a hydrophobic molecule, showed that the L-and the D-enantiomer exert more potent antibacterial or antifungal activity than their opposite enantiomer, respectively. Furthermore, we synthesized liposomes by using representative phospholipids consisting of bacterial or ...
Source: Journal of Peptide Science - July 15, 2009 Category: Biochemistry Authors: Juneyoung Lee, Cana Park, Seong-Cheol Park, Eun-Rhan Woo, Yoonkyung Park, Kyung-Soo Hahm, Dong Gun Lee Source Type: journals

Design of potent 9-mer antimicrobial peptide analogs of protaetiamycine and investigation of mechanism of antimicrobial actionEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we designed four 9-mer peptide analogs based on the sequence of RLWLAIGRG-NH2, in which Gly or Ile was substituted with Arg, Lys, or Trp to optimize the balance between the hydrophobicity and cationicity of the peptides and to increase bacterial cell selectivity. We measured their toxicity to bacteria and mammalian cells as well as their ability to permeabilize model phospholipid membranes. Substitution of Arg for Gly9 at the C-terminus (9Pbw1) resulted in two- to fourfold improvement in antibacterial activity. Further substitution of Gly7 with Lys (9Pbw2 and 9Pbw4) caused four- to eightfold improvement in t...
Source: Journal of Peptide Science - July 14, 2009 Category: Biochemistry Authors: Soyoung Shin, Jin-Kyoung Kim, Jee-Young Lee, Ki-Woong Jung, Jae-Sam Hwang, Juneyoung Lee, Dong Gun Lee, Iksoo Kim, Song Yub Shin, Yangmee Kim Source Type: journals

Antimicrobial peptide interactions with silica bead supported bilayers and E. coli: buforin II, magainin II, and arenicinEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Using the unique quantitative capabilities of hyperspectral confocal microscopy combined with multivariate curve resolution, a comparative approach was employed to gain a deeper understanding of the different types of interactions of antimicrobial peptides (AMPs) with biological membranes and cellular compartments. This approach allowed direct comparison of the dynamics and local effects of buforin II, magainin II, and arenicin with nanoporous silica bead supported bilayers and living E. coli. Correlating between experiments and comparing these responses have yielded several important discoveries for pursuing the underlyin...
Source: Journal of Peptide Science - July 8, 2009 Category: Biochemistry Authors: Ryan W. Davis, Dulce C. Arango, Howland D. T. Jones, Mark H. Van Benthem, David M. Haaland, Susan M. Brozik, Michael B. Sinclair Source Type: journals

Cationic oligopeptides with the repeating sequence L-lysyl-L-alanyl-L-alanine: conformational and thermal stability study using optical spectroscopic methodsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The infrared (IR), vibrational circular dichroism (VCD), and electronic circular dichroism (ECD) spectra of short cationic sequential peptides (L-Lys-L-Ala-L-Ala)n (n = 1, 2, and 3) were measured over a range of temperatures (20-90 °C) in aqueous solution at near-neutral pH values in order to investigate their solution conformations and thermally induced conformational changes. VCD spectra of all three oligopeptides measured in the amide I[prime] region indicate the presence of extended helical polyproline II (PPII)-like conformation at room temperature. UV-ECD spectra confirmed this conclusion. Thus, the oligopeptides ad...
Source: Journal of Peptide Science - July 4, 2009 Category: Biochemistry Authors: Vladimír Setni[ccaron]ka, Jan Hlavá[ccaron]ek, Marie Urbanová Source Type: journals

Screening for glucose-triggered modifications of glutathioneEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Nonenzymatic protein glycation is caused by a Schiff's base reaction between the aldehyde groups of reducing sugars and the primary amines of proteins. These structures may undergo further Amadori rearrangement and free radical-mediated oxidation to finally generate irreversible advanced glycation end products (AGEs). One of the factors known to modulate the glycation of proteins is glutathione, the most abundant nonprotein thiol tripeptide with the [gamma]-linkage, H-Glu(Cys-Gly-OH)-OH (GSH). Screening for products formed by GSH with D-glucose is an essential step in understanding the participation of GSH in glycation (th...
Source: Journal of Peptide Science - July 2, 2009 Category: Biochemistry Authors: Ivanka Jeri[cacute], [Scaron]tefica Horvat Source Type: journals

Inhibition of A[beta]42 aggregation using peptides selected from combinatorial librariesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Increasing evidence suggests that the aggregation of the small peptide A[beta]42 plays an important role in the development of Alzheimer's disease. Inhibiting the initial aggregation of A[beta]42 may be an effective treatment for preventing, or slowing, the onset of the disease. Using an in vivo screen based on the enzyme EGFP, we have searched through two combinatorially diverse peptide libraries to identify peptides capable of inhibiting A[beta]42 aggregation. From this initial screen, three candidate peptides were selected and characterized. ThT studies indicated that the selected peptides were capable of inhibiting amy...
Source: Journal of Peptide Science - June 26, 2009 Category: Biochemistry Authors: Michael Baine, Daniel S. Georgie, Elelta Z. Shiferraw, Theresa P. T. Nguyen, Luiza A. Nogaj, David A. Moffet Source Type: journals

An engineered tryptophan zipper-type peptide as a molecular recognition scaffoldEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In an effort to develop a structured peptide scaffold that lacks a disulfide bond and is thus suitable for molecular recognition applications in the reducing environment of the cytosol, we investigated engineered versions of the trpzip class of [beta]-hairpin peptides. We have previously shown that even most highly folded members of the trpzip class (i.e. the 16mer peptide HP5W4) are substantially destabilized by the introduction of mutations in the turn region and therefore not an ideal peptide scaffold. To address this issue, we used a FRET-based live cell screening system to identify extended trpzip-type peptides with a...
Source: Journal of Peptide Science - June 24, 2009 Category: Biochemistry Authors: Zihao Cheng, Robert E. Campbell Source Type: journals

Folding in solution of the C-catalytic protein fragment of angiotensin-converting enzymeEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present here the cloning, overexpression in Escherichia coli, purification and structural study of the Ala959 to Ser1066 region (ACE_C) that corresponds to the C-catalytic domain of human somatic angiotensin-I-converting enzyme. ACE_C was purified under denatured conditions and the yield was 6 mg/l of culture. Circular dichroism (CD) spectroscopy indicated that 1,1,1-trifluoroethanol (TFE) is necessary for the correct folding of the protein fragment. The described procedure can be used for the production of an isotopically labelled ACE959-1066 protein fragment in order to study its structure in solution by NMR spectrosc...
Source: Journal of Peptide Science - June 22, 2009 Category: Biochemistry Authors: Sotirios-Spyridon M. Vamvakas, Leondios Leondiadis, George Pairas, Evy Manessi-Zoupa, Georgios A. Spyroulias, Paul Cordopatis Source Type: journals

De novo generation of antimicrobial LK peptides with a single tryptophan at the critical amphipathic interfaceEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
De novo design of amphipathic model peptides has been successful for generating many antimicrobial peptides with various lengths and amino acid compositions. Here, we suggest a very simple strategy to design antimicrobial peptides with a short length and a simple amino acid composition. Amphipathic helical properties were conferred by using only leucines and lysines and a single tryptophan was positioned at the critical amphipathic interface between the hydrophilic ending side and the hydrophobic starting side, in the helical wheel projection. According to this rule, the model peptides with 7 to 13 residues exhibited antim...
Source: Journal of Peptide Science - June 18, 2009 Category: Biochemistry Authors: Su-Jin Kang, Hyung-Sik Won, Wahn-Soo Choi, Bong-Jin Lee Source Type: journals

Esculentin 1-21: a linear antimicrobial peptide from frog skin with inhibitory effect on bovine mastitis-causing bacteriaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mastitis, or inflammation of the mammary gland, is the most common and expensive illness of dairy cows throughout the world. Although stress and physical injuries may give rise to inflammation of the udders, infections by bacteria or other microorganisms remain the major cause, and infusion of antibiotics is the main treatment approach. However, the increased emergence of multidrug-resistant pathogens and the production of milk contaminated with antibiotics has become a serious threat in the livestock. Hence, there is an urgent need for the discovery of new therapeutic agents with a new mode of action. Gene-encoded AMPs, w...
Source: Journal of Peptide Science - June 10, 2009 Category: Biochemistry Authors: Alfonso Enrique Islas-Rodrìguez, Ludovica Marcellini, Barbara Orioni, Donatella Barra, Lorenzo Stella, Maria Luisa Mangoni Source Type: journals

Structure dependence of biological activities for primate cathelicidinsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have analysed the effects of variations in orang-utan (ppy), rhesus macaque (mmu) and leaf eater (pob) monkey orthologues of the human cathelicidin LL-37, on a range of relevant biological activities. These host defence peptides range in cationicity from +4 to +10, and while the more cationic pob and mmuRL-37 are in a monomeric and unstructured form in bulk solution (F-form), the human and ppyLL-37 are in an aggregated/helical form (A-form). The in vitro antibacterial activity depended strongly on both the structural form and the charge. F-form peptides were more potent against Gram-positive and -negative bacteria and l...
Source: Journal of Peptide Science - May 27, 2009 Category: Biochemistry Authors: Linda Tomasinsig, Francesca Morgera, Nikolinka Antcheva, Sabrina Pacor, Barbara Skerlavaj, Margherita Zanetti, Alessandro Tossi Source Type: journals

Structural determinants for selective recognition of peptide ligands for endothelin receptor subtypes ETA and ETBEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The molecular basis for recognition of peptide ligands endothelin-1, -2 and -3 in endothelin receptors is poorly understood. Especially the origin of ligand selectivity for ETA or ETB is not clearly resolved. We derived sequence-structure-function relationships of peptides and receptors from mutational data and homology modeling. Our major findings are the dissection of peptide ligands into four epitopes and the delineation of four complementary structural portions on receptor side explaining ligand recognition in both endothelin receptor subtypes. In addition, structural determinants for ligand selectivity could be descri...
Source: Journal of Peptide Science - May 24, 2009 Category: Biochemistry Authors: Jens Lättig, Alexander Oksche, Michael Beyermann, Walter Rosenthal, Gerd Krause Source Type: journals