Tuesday, January 24, 2012

synthetic peptides| What is synthetic peptides|Papers onsynthetic peptides |Research on synthetic peptides | Publications on synthetic peptides


1.
Bull Exp Biol Med. 2011 Feb;150(4):495-9.

Effects of peptides lys-glu-asp-gly and ala-glu-asp-gly on hormonal activity and structure of the thyroid gland in hypophysectomized young chickens and old hens.

[Article in English, Russian]

Source

Chita State Medical Academy, Russia. bi_kuznik@mail.ru.

Abstract

Hypophysectomy in 5-days chickens and old hens was followed by hormonal disturbances and structural changes in the thyroid gland. Administration of peptides Lys-Glu-Asp-Gly and Ala-Glu-Asp-Gly synthesized on the basis the amino acid composition of extracts from the anterior and posterior lobes of the pituitary gland, respectively, to hypophysectomized birds for 40 days significantly reduced the degree of these changes. The normalizing effect ofsynthetic peptides on the concentration of thyrotrophic hormone and thyroid hormones in old hens was less pronounced than in chickens.

PMID:
22268052
[PubMed - in process]
2.
J Biol Chem. 2012 Jan 20. [Epub ahead of print]

Tyrosines in the Carboxy-terminus of Syk once Phosphorylated Interact with Signaling Proteins including TULA-2, a Negative Regulator of Mast Cell Degranulation.

Source

NIDCR, United States.

Abstract

Activation of the high affinity IgE receptor (FcεRI) results in the tyrosine phosphorylation of two conserved tyrosines located close to the carboxy terminus of the protein tyrosine kinase Syk. Synthetic peptides representing the last ten amino acids of the tail of Syk with these two tyrosines either nonphosphorylated or phosphorylated were used to precipitate proteins from mast cell lysates. Proteins specifically precipitated by the phosphorylated peptide were identified by mass spectrometry. These included the adaptor proteins SLP-76, Nck-1, Grb2 and GADS and the proteins phosphatases SHIP-1 and UBASH3B (also known as TULA-2). The presence of these in the precipitates was further confirmed by immunoblotting. Using the peptides as probes in far westerns showed direct binding of the phosphorylated peptide to Nck-1 and SHIP-1. Immunoprecipitations suggested that there were complexes of these proteins associated with Syk especially after receptor activation; in these complexes are Nck, SHIP-1, SLP-76, Grb2 and TULA-2 (UBASH3B or STS-1). The decreased expression of TULA-2 by treatment of mast cells with siRNA increased the FcεRI-induced tyrosine phosphorylation of the activation loop tyrosines of Syk and the phosphorylation of phospholipase C-2γ. There was parallel enhancement of the receptor-induced degranulation and NFAT or NFκB activation indicating that TULA-2 like SHIP-1 functions as a negative regulator of FcεRI signaling in mast cells. Therefore the terminal tyrosines of Syk once phosphorylated bind complexes of proteins that are positive and negative regulators of signaling in mast cells.

PMID:
22267732
[PubMed - as supplied by publisher]
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3.
Chembiochem. 2012 Jan 20. doi: 10.1002/cbic.201100643. [Epub ahead of print]

Chemical Biology Approaches Reveal Conserved Features of a C-Terminal Processing PDZ Protease.

Source

Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstrasse 2, 45117 Essen (Germany).

Abstract

Several proteases like the high temperature requirement A (HtrA) protein family containing internal or C-terminal PDZ domains play key roles in protein quality control in the cell envelope of Gram-negative bacteria. While several HtrA proteases have been extensively characterized, many features of C-terminal processing proteases such as tail-specific protease (Tsp) are still unknown. To fully understand these cellular control systems, individual domains need to be targeted by specific peptides acting as activators or inhibitors. Here, we describe the identification and design of potent inhibitors and activators of Tsp. Suitable synthetic substrates of Tsp were identified and served as a basis for the generation of boronic acid-based peptide inhibitors. In addition, a proteomic screen of E. coli cell envelope proteins using a synthetic peptide library was performed to identify peptides capable of amplifying Tsp's proteolytic activity. The implications of these findings for the regulation of PDZ proteases and for future mechanistic studies are discussed.

Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PMID:
22267294
[PubMed - as supplied by publisher]
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4.
Chemistry. 2012 Jan 20. doi: 10.1002/chem.201101975. [Epub ahead of print]

Cu(II) Coordination Chemistry of Patellamide Derivatives: Possible Biological Functions of Cyclic Pseudopeptides.

Source

Universität Heidelberg, Anorganisch-Chemisches Institut, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany). peter.comba@aci.uni-heidelberg.de.

Abstract

Two synthetic derivatives of the naturally occurring cyclic pseudooctapeptides patellamide A-F and ascidiacyclamide, that is, H(4) pat(2) , H(4) pat(3) , as well as their Cu(II)  complexes are described. These cyclic peptide derivatives differ from the naturally occurring macrocycles by the variation of the incorporated heterocyclic donor groups and the configuration of the amino acids connecting the heterocycles. The exchange of the oxazoline and thiazole groups by dimethylimidazoles or methyloxazoles leads to more rigid macrocycles, and the changes in the configuration of the side chains leads to significant differences in the folding of the cyclic peptides. These variations allow a detailed study of the various possible structural changes on the chemistry of the Cu(II)  complexes formed. The coordination of Cu(II) with these macrocyclic species was monitored by high-resolution electrospray mass spectrometry (ESI-MS), spectrophotometric (UV/Vis) and circular dichroic (CD) titrations, and electron paramagnetic resonance (EPR) spectroscopy. Density functional theory (DFT) calculations and molecular mechanics (MM) simulations have been used to model the structures of the Cu(II)  complexes and provide a detailed understanding of their geometric preferences and conformational flexibility. This is related to the Cu(II)  coordination chemistry and the reactivity of the dinuclear Cu(II)  complexes towards CO(2) fixation. The variation observed between the natural and various synthetic peptide systems enables conclusions about structure-reactivity correlations, and our results also provide information on why nature might have chosen oxazolines and thiazoles as incorporated heterocycles.

Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PMID:
22266951
[PubMed - as supplied by publisher]
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5.
Anesthesiology. 2012 Jan 19. [Epub ahead of print]

Molecular Changes Induced in Rat Liver by Hemorrhage and Effects of Melanocortin Treatment.

Source

* Postdoctoral Fellow, Center for Surgical Research, ** Director, Center for Preclinical Investigation, Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico, Milano, Italy. † Assistant Professor of Pharmacology, ‡Postgraduate Student, # Postdoctoral Fellow, †† Full Professor of Pharmacology, Department of Biomedical Sciences, Section of Pharmacology, University of Modena and Reggio Emilia, Modena, Italy. § Research Assistant, Department of Internal Medicine, University of Milano, Milano, Italy. ‖ Associate Professor of Pharmaceutical Chemistry, Department of Pharmaceutical Chemistry and Toxicology, University of Napoli "Federico II," Napoli, Italy.

Abstract

BACKGROUND:

Melanocortin peptides improve hemodynamic parameters and prevent death during severe hemorrhagic shock. In the present research we determined influences of a synthetic melanocortin 1/4 receptor agonist on the molecular changes that occur in rat liver during hemorrhage.

METHODS:

Controlled-volume hemorrhage was performed in adult rats under general anesthesia by a stepwise blood withdrawal until mean arterial pressure fell to 40 mmHg. Then rats received either saline or the synthetic melanocortin 1/4 receptor agonist Butir-His-D-Phe-Arg-Trp-Sar-NH2 (Ro27-3225; n = 6-8 per group). Hemogasanalysis was performed throughout a 60-min period. Gene expression in liver samples was determined at 1 or 3 h using quantitative real-time polymerase chain reaction.

RESULTS:

At 1 h, in saline-treated shocked rats, there were significant increases in activating transcription factor 3 (Atf3), early growth response 1 (Egr1), heme oxygenase (decycling) 1 (Hmox1), FBJ murine osteosarcoma viral oncogene homolog (Fos), and jun oncogene (Jun). These changes were prevented by Ro27-3225 (mean ± SEM: Atf3 152.83 ± 58.62 vs. 579.00 ± 124.13, P = 0.002; Egr1 13.21 ± 1.28 vs. 26.63 ± 1.02, P = 0.001; Hmox1 3.28 ± 0.31 vs. 166.54 ± 35.03, P = 0.002; Fos 4.36 ± 1.03 vs. 14.90 ± 3.44, P < 0.001; Jun 6.62 ± 1.93 vs. 15.07 ± 2.09, P = 0.005; respectively). Increases in alpha-2-macroglobulin (A2m), heat shock 70kD protein 1A (Hspa1a), erythropoietin (Epo), and interleukin-6 (Il6) occurred at 3 h in shocked rats and were prevented by Ro27-3225 treatment (A2m 6.90 ± 0.82 vs. 36.73 ± 4.00, P < 0.001; Hspa1a 10.34 ± 3.28 vs. 25.72 ± 3.64, P = 0.001; Epo 0.49 ± 0.13 vs. 2.37 ± 0.73, P = 0.002; Il6 1.05 ± 0.15 vs. 1.88 ± 0.23, P < 0.001; respectively). Further, at 3 h in shocked rats treated with Ro27-3225 there were significant increases in tight junction protein 1 (Tjp1; 27.30 ± 2.43 vs. 5.03 ± 1.68, P < 0.001) and nuclear receptor subfamily 4, group A, member 1 (Nr4a1; 91.03 ± 16.20 vs. 30.43 ± 11.0, P = 0.01) relative to sham animals. Treatment with Ro27-3225 rapidly restored blood pressure, hemogasanalysis parameters, and lactate blood levels.

CONCLUSIONS:

Melanocortin treatment significantly prevents most of the systemic and hepatic detrimental changes induced by hemorrhage.

PMID:
22266570
[PubMed - as supplied by publisher]
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6.
Peptides. 2012 Jan 13. [Epub ahead of print]

Identification of cDNAs encoding allatotropin and allatotropin-like peptides from the silkworm, Bombyx mori.

Source

Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.

Abstract

The cDNAs encoding allatotropin (AT) and allatotropin-like peptides (ATLPs) were isolated from the silkworm, Bombyx mori. Similar to those of the tobacco hornworm, Manduca sexta, four peptides (AT, ATLP1, ATLP2, and ATLP3) are present in three different variants generated by alternative splicing. RT-PCR analyses showed that these splice variants are expressed in the central nervous system with differing expression patterns in each ganglion. Immunohistochemistry using an anti-AT antibody confirmed that AT-expressing cells were located in these central nervous ganglia as well as in two large anterior cells of the frontal ganglia. Injection of synthetic AT and ATLP-1 into B. mori larvae increased the latency to feed, indicating that AT and ATLP might function in the regulation of feeding behavior in B. mori.

Copyright © 2012. Published by Elsevier Inc.

PMID:
22265806
[PubMed - as supplied by publisher]
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7.
Bioconjug Chem. 2012 Jan 22. [Epub ahead of print]

Atrial natriuretic peptide-Fc, ANP-Fc, fusion proteins: semi-synthesis, in vitro activity and pharmacokinetics in rats.

Abstract

Atrial natriuretic peptide (ANP) may be a useful molecule for the treatment of cardiovascular diseases due to its potent natriuretic effects. In an effort to prolong the short in vivo half-life of ANP, fusions of the peptide to the Fc domain of IgG were generated using a semi-synthetic methodology. Synthetic ANP peptides were synthesized with thioesters at either the N- or C-termini of the peptide and subsequently linked to the N-terminus of recombinantly-expressed Fc using native chemical ligation. The linker length between the ANP and Fc moieties was varied between 2, 11 or 16 amino acids. In addition, either one ("monomeric") or two ("dimeric") ANP peptides were linked to Fc to study whether this modification had an effect on in vitro activity and/or in vivo half-life. The various constructs were studied for in vitro activity using a cell-based cGMP assay. The ANP-Fc fusion constructs were between 16 and ~375-fold weaker than unconjugated ANP in this assay, and a trend was observed where the most potent conjugates were those with longer linkers and in the dimeric configuration. The pharmacokinetics of several constructs were assessed in rats, and the half-life of the ANP-Fc's were found to be approximately two orders of magnitude longer than that of the unconjugated peptide. There was no significant difference in terminal half-life between the monomeric and dimeric constructs (2.8-5.5 h), but a trend was observed where the Cmax of the monomeric constructs was approximately 3-fold higher than the dimeric constructs, although the origin of this effect is not understood. These novel ANP-Fc fusion constructs hold promise for future therapeutic application in the treatment of cardiovascular diseases.

PMID:
22263969
[PubMed - as supplied by publisher]
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8.
Comb Chem High Throughput Screen. 2012 Jan 19. [Epub ahead of print]

SPED-(Styrene-Polyethyleneglycol Diacrylate-9-Decen-1-ol)- A Novel Resin for Solid Phase Peptide Synthesis; Synthesis and Characterization of Biologically Potent Endothelin Classes of Peptides.

Source

Chemical Biology, Rajiv Gandhi Centre for Biotechnology, Poojappura, Thiruvananthapuram- 695 014, Kerala, India. gsvinod@rgcb.res.in.

Abstract

Here we present a novel beaded chemically stable, highly permeable hydrophobic/hydrophilic balanced support for solid phase peptide synthesis. The resin (SPED) was prepared by free radical suspension polymerization using monomers styrene and 9-decen-1-ol with amphiphilic cross-linking agent polyethyleneglycol diacrylate (Mn≈ 258). Different cross-linking densities were prepared to check the extent of swelling in different polar and non-polar solvents. The SPED resin was characterized with IR, 13C NMR and surface by SEM. The chemical stability of the support in various peptidesynthetic conditions was investigated and monitored by IR spectroscopy. To evaluate the applicability of the new resin insynthetic conditions more challenging peptide sequence of retro-ACP (74-65) was synthesized and compared to commercially available Merrifield resin. The efficiency of SPED was further confirmed by synthesizing biologically important endothelin family of peptides in high yield and purity. The purity of all peptides was checked by RP-HPLC and mass by MALDI-TOF MS.

PMID:
22263861
[PubMed - as supplied by publisher]
9.
Biomed Mater. 2012 Jan 20;7(1):012002. [Epub ahead of print]

Recombinant protein scaffolds for tissue engineering.

Source

CSIRO Materials Science and Engineering, Bayview Avenue, Clayton 3169, Australia.

Abstract

New biological materials for tissue engineering are now being developed using common genetic engineering capabilities to clone and express a variety of genetic elements that allow cost-effective purification and scaffold fabrication from these recombinant proteins, peptides or from chimeric combinations of these. The field is limitless as long as the gene sequences are known. The utility is dependent on the ease, product yield and adaptability of these protein products to the biomedical field. The development of recombinant proteins as scaffolds, while still an emerging technology with respect to commercial products, is scientifically superior to current use of natural materials or synthetic polymer scaffolds, in terms of designing specific structures with desired degrees of biological complexities and motifs. In the field of tissue engineering, next generation scaffolds will be the key to directing appropriate tissue regeneration. The initial period of biodegradable synthetic scaffolds that provided shape and mechanical integrity, but no biological information, is phasing out. The era of protein scaffolds offers distinct advantages, particularly with the combination of powerful tools of molecular biology. These include, for example, the production of human proteins of uniform quality that are free of infectious agents and the ability to make suitable quantities of proteins that are found in low quantity or are hard to isolate from tissue. For the particular needs of tissue engineering scaffolds, fibrous proteins like collagens, elastin, silks and combinations of these offer further advantages of natural well-defined structural scaffolds as well as endless possibilities of controlling functionality by genetic manipulation.

PMID:
22262725
[PubMed - as supplied by publisher]
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10.
J Dermatol Sci. 2011 Dec 30. [Epub ahead of print]

Mapping of B cell epitopes on desmoglein 3 in pemphigus vulgaris patients by the use of overlapping peptides.

Source

Department of Dermatology, University of Lübeck, Lübeck, Germany.

Abstract

BACKGROUND:

Pemphigus vulgaris (PV) is a severe autoimmune blistering disease associated with autoantibodies to desmoglein 3 (Dsg 3), a transmembrane glycoprotein of the cadherin family. Previous studies mainly focused on the mapping of conformational epitopes of Dsg 3 using recombinant fragments of Dsg 3 and competition ELISA.

OBJECTIVE:

Here, we performed a mapping of linear B cell epitopes on Dsg 3 in PV patients by the use of overlappingsynthetic peptides.

METHODS:

A set of 254 overlapping synthetic peptides of 14 amino acids length covering the entire Dsg 3 extracellular domain was generated. Sera of patients with active PV (n=10) and healthy volunteers (n=10) were tested for IgG reactivity with the 254 peptides by ELISA. Testing each peptide separately, 7 major antigenic sites were identified. In order to validate these reactivities, 7 corresponding peptides of 13-33 amino acids in length were generated and employed by ELISA. Additional sera of active PV patients (n=17) and healthy volunteers (n=20) were tested and the most reactive peptide was used to specifically purify anti-Dsg 3 antibodies from PV sera (n=3).

RESULTS:

The major autoantibody reactivity in PV sera was mapped to amino acids 333-356 within the EC3 domain. Purifying patients IgG using the identified peptide, however, failed to induce acantholysis in keratinocyte dissociation assay.

CONCLUSION:

We conclude that linear epitopes do not play a major pathogenic role in human PV.

Copyright © 2011 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

PMID:
22261006
[PubMed - as supplied by publisher]
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11.
Trends Biotechnol. 2012 Jan 17. [Epub ahead of print]

Exploiting cell surface thiols to enhance cellular uptake.

Source

Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.

Abstract

Efficient cellular delivery is one of the key issues that has hampered the therapeutic development of novel syntheticbiomolecules such as oligonucleotides, peptides and nanoparticles. The highly specialized cellular plasma membrane specifically internalizes compounds through tightly regulated mechanisms. It is possible to exploit these natural mechanisms of cellular uptake with rationally designed reagents. Here, we discuss how thiol groups (-SH) naturally present on the cell surface (exofacial thiols) can be used to enhance cellular association and internalization of various materials bearing thiol-reactive groups in their structure. We propose that such thiol modifications should be considered in future design of synthetic biomolecules for optimized cellular delivery.

Copyright © 2011 Elsevier Ltd. All rights reserved.

PMID:
22260747
[PubMed - as supplied by publisher]
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12.
J Virol. 2012 Jan 18. [Epub ahead of print]

INHIBITION OF THE LATENT MEMBRANE PROTEIN-1 IMPAIRS THE GROWTH AND TUMORIGENESIS OF AN EBV-LATENCY II TRANSFORMED T-CELL.

Source

CNRS UMR8161, Institut de Biologie de Lille, IFR 142, Université Lille-Nord de France, 1 rue du Pr Calmette, 59021 Lille Cedex.

Abstract

The Epstein-Barr virus (EBV) is a common human herpes virus. Its infection is associated with several human malignancies where it expresses a set of latent proteins among which is the latent membrane protein LMP1. LMP1 is able to transform numerous cell types and is considered the main oncogenic protein of EBV. The mechanism of action is based on mimicry to activated members of the TNF receptor superfamily, through its ability to bind similar adapters and to activate signaling pathways. We previously generated two unique models: a monocytic and lymphocytic (NC5) cell line immortalized by EBV which expresses the type II latency program.Here, we generated LMP1 dominant negatives (DNs), based on fusion between green fluorescent protein (GFP) and TES1 or TES2 (Transformation Effectors Site) of LMP1. Then, we generated cell lines conditionally expressing these DNs. These DNs inhibit NFkB and Akt pathways resulting in impairment of survival processes and increased apoptosis in these cell lines. This pro-apoptotic effect is due to reduced interaction of LMP1 with specific adapters and the recruitment of these adapters to DNs which enable generation of an apoptotic complex involving TRADD, FADD and caspase-8. Similar results were obtained with cell lines displaying a latency III program in which LMP1-DNs decrease cell viability. Finally, we prove that syntheticpeptides display similar inhibitory effects in EBV infected cells. DNs derived from LMP1 could be used to develop therapeutic approaches in malignant diseases associated with EBV.

PMID:
22258264
[PubMed - as supplied by publisher]
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13.
J Proteome Res. 2012 Jan 18. [Epub ahead of print]

The Precision of Heavy-Light Peptide Ratios Measured by MALDI-TOF Mass Spectrometry.

Abstract

We have investigated the precision of peptide quantitation by MALDI-TOF mass spectrometry (MS) using 6 pairs of proteotypic peptides (light) and same-sequence stable isotope labeled synthetic internal standards (heavy). These were combined in two types of dilution curves spanning 100-fold and 2,000-fold ratios. Coefficients of variation (CV; standard deviation divided by mean value) were examined across replicate MALDI spots using a reflector acquisition method requiring 100,000 counts for the most intense peak in each summed spectrum. The CV of light/heavy peptide centroid peak area ratios determined on 4 replicate spots per sample, averaged across 11 points of a 100-fold dilution curve and over all 6 peptides, was 2.2% (ranging from 1.5-3.7% among peptides) at 55 fmol total (light + heavy) of each peptide applied per spot, and 2.5% at 11 fmol applied. The average CV of measurements at near-equivalence (light = heavy, the center of the dilution curve) for the six peptides was 1.0%, about 17-fold lower CV than that observed when 5 peptideswere ratio'ed to a sixth peptide (i.e., a different-sequence internal standard). Response curves across the 100-fold range were not completely linear, but could be closely modeled by a power law fit giving R2 values > 0.998 for all peptides. The MALDI-TOF MS method was used to determine the endogenous level of a proteotypic peptide (EDQYHYLLDR) of human protein C inhibitor (PCI) in a plasma digest after enrichment by capture on a high affinity anti-peptide antibody, a technique called Stable Isotope Standards and Capture by Anti-Peptide Antibodies (SISCAPA). The level of PCI was determined to be 770 ng/mL with a replicate measurement CV of 1.5% and a >14,000-fold target enrichment via SISCAPA. These results indicate that MALDI-TOF technology can provide precise quantitation of high-to-medium abundance peptide biomarkers over a 100-fold dynamic range when ratio'ed to same-sequence labeled internal standards and enriched to near purity by specific antibody capture. The robustness and throughput of MALDI-TOF in comparison to conventional nano-LC-MS technology could enable currently impractical large-scale verification studies of protein biomarkers.

PMID:
22257466
[PubMed - as supplied by publisher]
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14.
J Pept Sci. 2012 Jan 17. doi: 10.1002/psc.1436. [Epub ahead of print]

Determination of counter-ions in synthetic peptides by ion chromatography, capillary isotachophoresis and capillary electrophoresis.

Source

Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdansk, al. Hallera 107, 80-416, Gdansk, Poland. wojmrozik@gumed.edu.pl.

Abstract

The utility of three various analytical techniques [ion chromatography (IC), capillary electrophoresis (CE) and isotachophoresis (ITP)] was tested in the determination of counter-ions in synthetic peptides. The analyzed ions were acetates, trifluoroacetates and chlorides. IC provided the best results; CE, except limit of detection and limit of quantification, exhibited the comparable results. ITP was classified as the less useful because of the problem with the determination of the chloride ions. Nevertheless, all the three techniques were able to analyze trifluoroacetates and acetates ions with satisfactory results. Except analytical methods, three procedures using hydrochloric acid (HCl) (at two different concentrations) and acetic acid as sample solvents processed by lyophilization were tested. It has been found that the lyophilization not only by HCl but also by acetic acid is a simple and cheap procedure for removal of toxic trifluoroacetic counter-ions from peptides on satisfactory levels. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

PMID:
22252914
[PubMed - as supplied by publisher]
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15.
J Pept Sci. 2012 Jan 16. doi: 10.1002/psc.1434. [Epub ahead of print]

Synthesis of anticancer heptapeptides containing a unique lipophilic β(2,2) -amino acid building block.

Source

Department of Pharmacy, Faculty of Health Sciences, University of Tromsø, NO-9037, Tromsø, Norway.

Abstract

We report a series of synthetic anticancer heptapeptides (H-KKWβ(2,2) WKK-NH(2) ) containing eight different central lipophilic β(2,2) -amino acid building blocks, which have demonstrated high efficiency when used as scaffolds in small cationic antimicrobial peptides and peptidomimetics. The most potent peptides in the present study had IC(50) values of 9-23 µm against human Burkitt's lymphoma and murine B-cell lymphoma and were all nonhaemolytic (EC(50)  > 200 µm). The most promising peptide 10e also demonstrated low toxicity against human embryonic lung fibroblast cells and peripheral blood mononuclear cells and exceptional proteolytic stability. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

PMID:
22249949
[PubMed - as supplied by publisher]
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16.
J Pept Sci. 2012 Jan 16. doi: 10.1002/psc.1430. [Epub ahead of print]

The use of 2,2'-dithiobis(5-nitropyridine) (DTNP) for deprotection and diselenide formation in protected selenocysteine-containing peptides.

Source

Department of Chemistry, Saint Michael's College, One Winooski Park, Colchester, VT, 05439, USA.

Abstract

In contrast to the large number of sidechain protecting groups available for cysteine derivatives in solid phase peptide synthesis, there is a striking paucity of analogous selenocysteine Se-protecting groups in the literature. However, the growing interest in selenocysteine-containing peptides and proteins requires a corresponding increase in availability ofsynthetic routes into these target molecules. It therefore becomes important to design new sidechain protection strategies for selenocysteine as well as multiple and novel deprotection chemistry for their removal. In this paper, we outline the synthesis of two new Fmoc selenocysteine derivatives [Fmoc-Sec(Meb) and Fmoc-Sec(Bzl)] to accompany the commercially available Fmoc-Sec(Mob) derivative and incorporate them into two model peptides. Sec-deprotection assays were carried out on these peptides using 2,2'-dithiobis(5-nitropyridine) (DTNP) conditions previously described by our group. The deprotective methodology was further evaluated as to its suitability towards mediating concurrent diselenide formation in oxytocin-templated target peptides. Sec(Mob) and Sec(Meb) were found to be extremely labile to the DTNP conditions whether in the presence or absence of thioanisole, whereas Sec(Bzl) was robust to DTNP in the absence of thioanisole but quite labile in its presence. In multiple Sec-containing model peptides, it was shown that bis-Sec(Mob)-containing systems spontaneously cyclize to the diselenide using 1 eq DTNP, whereas bis-Sec(Meb) and Sec(Bzl) models required additional manipulation to induce cyclization. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

PMID:
22249911
[PubMed - as supplied by publisher]
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17.
Mycopathologia. 2012 Jan 17. [Epub ahead of print]

Synthetic Peptides Mimic gp75 from Paracoccidioides brasiliensis in the Diagnosis of Paracoccidioidomycosis.

Source

Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de São Paulo-Escola Paulista de Medicina, Disciplina de Imunologia, Rua Botucatu, 862, 4º andar, São Paulo, 04023-900, Brazil.

Abstract

Paracoccidioidomycosis (PCM) is a systemic granulomatous disease, endemic in Latin America, caused by the thermal dimorphic fungus Paracoccidioides brasiliensis. Although some fungal antigens have already been characterized and used for serological diagnosis, cross-reactions have been frequently observed. Thus, the examination of fungal forms in clinical specimens or isolation of P. brasiliensis by culture is still the most frequent method for the diagnosis of this mycosis. In this study, a random peptide phage display library was used to select mimotopes of P. brasiliensis, which were employed as antigens in an indirect enzyme-linked immunosorbent assay. The protective monoclonal antibody against experimental PCM (anti-gp75) was used as molecular target to screen a phage display library. That approach led to a synthetic peptide named P2, which was synthesized and tested against PCM patients' sera to check whether it was recognized. There was significant recognition of P2 by sera of untreated PCM patients when compared with normal human sera. Sera from treated PCM group, patients with other mycosis or co-infected with HIV had much lower recognition of P2 than untreated patient group. The test showed a sensitivity of 100 and 94.59% of specificity in relation to human sera control. These data indicate a potential use of P2 as diagnostic tool in PCM. Its application for serological diagnosis of PCM may contribute to the development and standardization of simpler, faster and highly reproducible immunodiagnostic tests at low cost.

PMID:
22249604
[PubMed - as supplied by publisher]
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18.
Plant Cell. 2012 Jan 13. [Epub ahead of print]

The Apoplastic Oxidative Burst Peroxidase in Arabidopsis Is a Major Component of Pattern-Triggered Immunity.

Source

School of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom.

Abstract

In plants, reactive oxygen species (ROS) associated with the response to pathogen attack are generated by NADPH oxidases or apoplastic peroxidases. Antisense expression of a heterologous French bean (Phaseolus vulgaris) peroxidase (FBP1) cDNA in Arabidopsis thaliana was previously shown to diminish the expression of two Arabidopsis peroxidases (peroxidase 33 [PRX33] and PRX34), block the oxidative burst in response to a fungal elicitor, and cause enhanced susceptibility to a broad range of fungal and bacterial pathogens. Here we show that mature leaves of T-DNA insertion lines with diminished expression of PRX33 and PRX34 exhibit reduced ROS and callose deposition in response to microbe-associated molecular patterns (MAMPs), including the synthetic peptides Flg22 and Elf26 corresponding to bacterial flagellin and elongation factor Tu, respectively. PRX33 and PRX34 knockdown lines also exhibited diminished activation of Flg22-activated genes after Flg22 treatment. These MAMP-activated genes were also downregulated in unchallenged leaves of the peroxidase knockdown lines, suggesting that a low level of apoplastic ROS production may be required to preprime basal resistance. Finally, the PRX33 knockdown line is more susceptible to Pseudomonas syringae than wild-type plants. In aggregate, these data demonstrate that the peroxidase-dependent oxidative burst plays an important role in Arabidopsis basal resistance mediated by the recognition of MAMPs.

PMID:
22247251
[PubMed - as supplied by publisher]
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19.
J Leukoc Biol. 2012 Jan 13. [Epub ahead of print]

The role of the Src family kinase Lyn in the immunomodulatory activities of cathelicidin peptide LL-37 on monocytic cells.

Source

Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.

Abstract

Cathelicidin LL-37 is a multifunctional, immunomodulatory and antimicrobial host-defense peptide of the human immune system. Here, we identified the role of SFKs in mediating the chemokine induction activity of LL-37 in monocytic cells. LL-37 induced SFK phosphorylation; and chemical inhibitors of SFKs suppressed chemokine production in response to LL-37 stimulation. SFKs were required for the downstream activation of AKT, but Ca(2+)-flux and MAPK induction were SFK-independent. Through systematic siRNA knockdown of SFK members, a requirement for Lyn in mediating LL-37 activity was identified. The involvement of Lyn in cathelicidin activities was further confirmed using Lyn-knockout mouse BMDMs. The role of SFKs and Lyn was also demonstrated in the activities of the synthetic cationic IDR peptides, developed as novel, immunomodulatory therapeutics. These findings elucidate the common molecular mechanisms mediating the chemokine induction activity of natural and synthetic cationic peptides in monocytic cells and identify SFKs as a potential target for modulating peptide responses.

PMID:
22246800
[PubMed - as supplied by publisher]
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20.
Biophys Chem. 2011 Dec 24. [Epub ahead of print]

Characterization of channel-forming peptide nanostructures.

Abstract

We have prepared fluorescent analogs of known ion-channel-forming synthetic peptide nanostructures. These analogs were designed as probes to gain insight about the mechanism by which self-assembling amphiphilic peptides interact with lipid membranes. Conformational studies demonstrated that the labeled analogs retain their propensity to adopt a strong helical conformation in 2,2,2-trifluoroethanol and lipid bilayers. Attenuated total reflectance results indicated that the fluorescent peptide nanostructures are under an incorporation equilibrium between two forms, adsorbed at the surface or incorporated within the bilayer, similar to their unlabeled counterparts. However, when using a HeLa mimicking membrane, the proportion of peptide nanostructures in the transmembrane orientation decreases significantly. Finally, we were able to show by confocal microscopy studies that fluorescent analogs internalized into HeLa cells and localized into both the membranes of inner organelles and the cell membrane.

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