摘要:

AbstractRegulatory pressure has compelled the chemical manufacturing industry to reduce the use of organic solvents in synthetic chemistry, and there is currently a strong focus on replacing these solvents with water. Here, we describe an efficient in‐water solution‐phase peptide synthesis method using Boc‐amino acids. It is based on a coupling reaction utilizing suspended water‐dispersible nanoparticle reactants. Using this method, peptides were obtained in good yield and with high purity. Copyright © 2011 European Peptide Society and John Wiley&S

ISSN:1075-2617    

DOI:10.1002/psc.1367

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractWe previously reported that a novel targeted drug termed hybrid epidermal growth factor receptor (EGFR)‐lytic peptide, made by chemical conjugation of targeted binding peptide and cell‐killing, lytic‐peptide components, has selective cytotoxic activity that allows it to discriminate between normal and cancer cells. In addition,in vivoanalysis revealed that this hybrid peptide displays significant antitumor activity in a xenograft model of human breast and pancreatic cancer in mice. Here, we characterized antilytic peptide antibody, which was raised from rabbit serum using the antigen of lytic peptide conjugated with keyhole limpet hemocyanin. It was found that antilytic peptide antibody is specific to the lytic peptide as assessed by both ELISA and surface plasmon resonance analysis and can also bind to EGFR‐lytic peptide. Epitope mapping analysis using Biacore showed that two successive lysine regions in the lytic‐peptide sequence are significant for recognition by this antibody. In addition, it was shown that this antibody can detect lytic‐based hybrid peptide in serum samples from mouse blood and also in cultured breast cancer MDA‐MB‐231 cell samples by immunocytochemical staining experiments. It was found that the maximum concentrations of this peptide in serum were reached within 15–30 min of i.v. administration of EGFR‐lytic peptide to mice. These results indicate that this antibody will be a useful tool for the detection of lytic‐based peptides to investigate theirin vivostability and pharmacokinetics. Copyright © 2011 European Peptide Society an

ISSN:1075-2617    

DOI:10.1002/psc.1349

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractHuman glucagon‐like peptide‐1 (hGLP‐1) and its mimetics have emerged as therapies for type 2 diabetes. However, clinical treatment of diabetes with hGLP‐1 is ineffective because of rapid DPPIV‐mediated hGLP‐1 degradation in the circulation. In this study, we investigated the protective effect of recombinant human glucagon‐like peptide‐1 (rhGLP‐1) treatment on STZ‐induced diabetic mice. Mice were treated daily with rhGLP‐1 (24 nmol/kg body weight) starting before or after STZ injection (40 mg/kg body weight) to induce diabetes. Mice pretreated with rhGLP‐1 before but not after STZ showed significantly reduced blood glucose levels (P<0.05), increased oral glucose tolerance (area under the curve, 1740 ± 71.18 vs 2416 ± 205.6,P<0.05). Furthermore, the bioproduct of lipid peroxidation, MDA, was reduced and SOD and GSH‐PX activities were enhanced globally and in pancreas of mice that received rhGLP‐1 pretreatment before STZ, when comparing with STZ‐treated mice. Finally, STZ‐induced pancreatic islet damage was rescued by rhGLP‐1 pretreatment. Taken together, the results of this study demonstrate that rhGLP‐1 pretreatment has a protective effect against STZ‐induced diabetes in mice. These findings suggest that the GLP‐1 pretreatment may be a new therapeutic strategy in the preventive and protective treatment during diabetes initiation and progression. Copyright © 2011 Europea

ISSN:1075-2617    

DOI:10.1002/psc.1352

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractDivalent metal‐ion transporter 1 (DMT1) belongs to a large class of metal‐ion transporters that drive the translocation of a wide range of divalent metal substrates across membranes toward the cytosol with couple of protons. Two highly conserved histidines in the sixth transmembrane domain (TMD6) are essential for metal transport activity in DMT1. In the present study, we determine the high‐resolution structures of three 25‐residue peptides, corresponding to TMD6 of the wildtype DMT1 (the segment 255–279) and its H267A and H272A mutants, in 30% TFE‐d2aqueous solution by the combined use of circular dichroism (CD) and NMR spectroscopies. The wildtype peptide forms an ‘α‐helix‐extended segment‐α‐helix’ structure with two helices spanning over Gly258–Ala262 and Met265–Lys277 linked by a hinge at residues Val263–Ile264. The H267A mutation reduces the hinge to one residue (Ile264), while the H272A mutation extends the flexible region of the central part from Val263 to His267. Diffusion‐ordered spectroscopy (DOSY) study demonstrates that all the peptides are self‐assembly as trimer in 30% TFE‐d2aqueous solution. The H272A substitution decreases the intermolecular interaction whereas the H267A substitution may enhance the intermolecular interaction. The specific structure of the discontinuous helix and the self‐assembly feature of DMT1–TMD6 may be crucial for its biological function. The changes in conformation and intermolecular interaction induced by histidine substitution may be correlated with the deficiency of DMT1 in metal‐ion permeation. Copyright © 2011 Europ

ISSN:1075-2617    

DOI:10.1002/psc.1356

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractThe role of silver ions in various pathologies, as well as their effect on peptide conformation and properties are less understood. Consequently, we synthesized several peptides with various residues in their sequence to investigate silver‐induced conformational changes at various pH values by Circular Dichroism spectroscopy. Uniquely, the glycine‐based, histidine‐containing peptide showed a severe change from a random coil and β‐turn conformation to large α‐helices during silver binding. When comparing the effect of silver ions on the conformation of bradykinin a similar tendency was found. Besides, silver ions reduced the amyloid‐β peptide tendency to aggregation. Our results suggest a specific and protective role for silver ions in brain pathologies, which is related to their high affinity toward physiologically and pharmacologically active peptides. Fourier transform infrared spectroscopy studies as well as the mass spectrometric ones support our conclusions. Copyright © 2011 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.1359

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractAntimicrobial peptides are major components of the innate self‐defence system and a large number of peptides have been designed to study the mechanism of action. In the present study, a small combinatorial library was designed to study whether the biological activity of Val/Arg‐rich peptides is associated with targeted cell membranes. The peptides were produced by segregating hydrophilic residues on the polar side and hydrophobic residues on the opposite side. The peptides displayed strong antimicrobial activity against Gram‐negative and Gram‐positive bacteria, but weak haemolysis even at a concentration of 256 µM. CD spectra showed that the peptides formed α‐helical‐rich structure in the presence of negatively charged membranes. The tryptophan fluorescence and quenching experiments indicated that the peptides bound preferentially to negatively charged phospholipids over zwitterionic phospholipids, which corresponds well with the biological activity data. In thein vivoexperiment, the peptide G6 decreased the bacterial counts in the mouse peritoneum and increased survival after 7 days. Overall, a high binding affinity with negatively charged phospholipids correlated closely with the cell selectivity of the peptides and some peptides in this study may be likely candidates for the development of antibacterial agents. Copyright © 2011 European Peptide Society and John W

ISSN:1075-2617    

DOI:10.1002/psc.1360

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractThe development of a multigram synthesis of the orthogonally protected amino acid‐derived Phaol [2‐{[(2S)‐2‐amino‐3‐phenylpropyl]amino}ethanol]is described. The goal of this work is to synthesize an orthogonally protected Phaol in a multigram scale up to 10 g (Cbz‐Phaol), so it can be used in solution‐based peptide synthesis of peptaibols. Two synthetic schemes were proposed and examined. Between the reduction‐coupling and the coupling‐reduction scheme, the latter gave the best results. A two‐step synthesis affords easily purifiable products. Several analogs were synthesized using this methodology. All the molecules were orthogonally protected, so that they can be used in peptide synthesis. Deprotection posed no problems. Copyright © 2011 European Peptide Society an

ISSN:1075-2617    

DOI:10.1002/psc.1362

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractOn the basis of the total synthesis of obyanamide, 20 analogues of this marine cyclic depsipeptide have been synthesized by (i) preparation of the tripeptide fragments in the western hemisphere using Z/OtBu protocol; (ii) preparation of the dipeptide fragments in the eastern hemisphere using Boc/OMe protocol; and (iii) fragments coupling, removal of protecting groups (Boc and OtBu, in one pot), and macrocyclizaion in the last step. The cytotoxic test showed that three synthetic compounds exhibited moderate activities against HL‐60, KB, LOVO, and A549 cell lines. According to the results, the β‐amino acid residue was found to play a critical role in the biological activities. Additionally, the ester bond along with the Ala(Thz) moiety was also essential for biological activities. However, it seems too early to draw a conclusion that theN‐methylation of Val/Phe can lead to higher or lower cytotoxic activities. Copyright © 2011 European Peptide Society and John Wiley&So

ISSN:1075-2617    

DOI:10.1002/psc.1361

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY

摘要:

AbstractThe defensin‐like antimicrobial peptides have been characterized from various other arthropods including insects, scorpions, and ticks. But no natural spider defensin‐like antimicrobial peptides have ever been isolated from spiders, except couple of cDNA and DNA sequences of five spider species revealed by previous genomic study. In this work, a defensin‐like antimicrobial peptide named Oh‐defensin was purified and characterized from the venoms of the spider,Ornithoctonus hainana. Oh‐defensin is composed of 52 amino acid (aa) residues including six Cys residues that possibly form three disulfide bridges. Its aa sequence is MLCKLSMFGAVLGV PACAIDCLPMGKTGGSCEGGVCGCRKLTFKILWDKKFG. By BLAST search, Oh‐defensin showed significant sequence similarity to other arthropod antimicrobial peptides of the defensin family. Oh‐defensin exerted potent antimicrobial activities against tested microorganisms including Gram‐positive bacteria, Gram‐negative bacteria, and fungi. The cDNA encoding Oh‐defensin precursor was also cloned from the cDNA library ofO. hainana.Copyright © 2011 European Peptide Society and

ISSN:1075-2617    

DOI:10.1002/psc.1370

出版商:John Wiley&Sons, Ltd.    

年代:2011

数据来源: WILEY