摘要:

AbstractThe formylpeptides formyl‐methionyl‐Nmethylleucyl‐ phenylaline methyl ester [for‐Met‐(NMe)Leu‐Phe‐OMe]1, formyl‐methionyl‐2‐aminotetralin‐2‐carboxyl‐phenylalanine methyl ester [for‐Met Act‐Phe‐OMe]2, formyl‐methionyl‐1,2,3,4‐terahydroisoquinoline‐3‐carboxl‐ phenylalanine methyl ester [for‐Met‐Tic‐Phe‐OMe]3and formyl‐ methionyl‐2‐aminoxy‐4‐methylvaleryl‐phenylalanine methyl ester [for‐Met‐OLeu‐Phe‐OMe]4were synthesized in order to investigate the role of the amide bond at position 2 on biological activities on human neutrophils. Only analogue 2, which keeps the NH group

ISSN:1075-2617    

DOI:10.1002/psc.55

出版商:John Wiley&Sons, Ltd.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe relation between the various spatial structures of the gramicidin A channels and their ionic conductance has been studied. For this aim, various conformations of the peptide were pre‐formed in liposomal bilayer and after subsequent fusion of liposomes with planar lipid bilayer the measured channel conductance was correlated with gramicidin structures established in liposomes. To form the single‐stranded π6.3π 6.3 helix the peptide and lipid were co‐dissolved in TFE prior to liposome preparation. THF and other solvents were used to form parallel (↑ ↑ π π) and antiparallel (↑ ↓ π π) double helices. Conformation of gramicidin in liposomes made by various phosphatidylcholines was monitored by CD spectroscopy, and computer analysis of the spectra obtained was performed. After fusion of gramicidin containing liposomes with planar bilayer membranes from asolectin, the histograms of single‐channel conductance were obtained. The histograms had one or three distinct peaks depending on the liposome preparation. Assignment of the structure of the channel to conductance levels was made by correlation of CD data with conductance histograms. The channel‐forming analogue, des(Trp‐Leu)2‐gramicidin A, has been studied by the same protocol. The channel conductances of gramicidin A and the shortened analogue increase in the following order: ↑ ↓ π π 2 ↑ ↑ π π<π 6.3π6.3. Single‐channels formed by double helices have higher dispersity of conductance than the π6.3π6.3 helical channel. Lifetimes of the double helical and the π6.3π6.3 helical channels are very close to each other. The data obtained were compared with theoretic

ISSN:1075-2617    

DOI:10.1002/psc.59

出版商:John Wiley&Sons, Ltd.    

年代:1996

数据来源: WILEY

摘要:

AbstractPseudobactin is a structurally complex and physiologically important siderophore (microbial iron chelator) fromPseudomonas putida‐ fluorescens. Various fragments of the unusual peptide component of pseudobactin listed below were prepared by solution‐phase peptide synthesis.L‐Lys·D‐threo‐β‐OH Asp·L‐Ala·D‐allo‐Thr·L‐AlaL‐Lys·D‐threo‐βOH Asp·L‐Ala·D‐allo‐ThrD‐threo‐β‐OH Asp·L‐Ala·D‐allo‐Thr·L‐Ala·D‐N‐OH‐cycloOrnD‐threo‐β‐OH‐Asp·L‐Ala·D‐allo‐Thr·L‐AlaL‐Ala·D‐allo‐Thr·L‐ Ala·D‐N‐OH‐cycloOrnA class of related peptides named pseudomycins have shown promising antifungal activity. To examine if these peptide fragments above would elicit sim

ISSN:1075-2617    

DOI:10.1002/psc.61

出版商:John Wiley&Sons, Ltd.    

年代:1996

数据来源: WILEY

摘要:

AbstractThe hypervariable domain of the HIV gp120, the V3 loop domain, represents a target for neutralizing antibodies and for HIV vaccine strategies. In this study, we have investigated in murine species the potential cross‐reactivity of immune responses elicited by immunization either with individual V3 peptides, derived from distinct HIV sequences (BRU, RF, SF2, MN and ELI sequences), or with a V3 combinatorial peptide library.We observed that individual V3 peptides are immunogenic but elicit a specific B‐ and T‐cell immune response that is mainly restricted to the sequence of the immunizing peptide. In particular, T‐cell responses that depend on T‐cell receptor recognition of peptides bound to the molecules encoded by the major histocompatibility complex were significantly influenced by small differences in the peptide amino acid sequence. The combinatorial V3 peptide library, previously described as B‐ and T‐cell immunogens, induced a more broadly reactive immune response, specially when T‐cell cytokine secretion was used as a readout for restimulation of T‐cells with individual V3 peptides.These data suggest that amino acid variations in the sequence of an antigenic peptide could lead to the induction of different transducing signals in the primed T‐cell population and to the activation of T‐cells with distinct cytokine secretion properties. These observations may have implications in the understanding of antigenic variability and in the design

ISSN:1075-2617    

DOI:10.1002/psc.54

出版商:John Wiley&Sons, Ltd.    

年代:1996

数据来源: WILEY

摘要:

AbstractNeuropeptide Y (NPY), a peptide amide comprising 36 residue has been shown to act as a potent vasoconstrictor. In order to shed light on the structural requirements for the biological activities with respect to the different prerequisites for affinity to the NPY receptor subtypes Y1and Y2, in the present study the syntheses and conformational analyses of two C‐terminal segments, NPY(18–36) and NPY(13–36), are described.The results obtained by CD measurements, two‐dimensional NMR spectros copy and a conformational refinement of the NMR‐derived structure by molecular mechanics simulations support the findings of previously published structure –activity relationship studies for biologically active and selective compounds. In particular, the α‐helical conformation as well as an appropriate exposure of the side chains of the critical C‐terminal dipeptide within NPY(18–36) are in agreement with the prerequisites proposed for Y2receptor bindi

ISSN:1075-2617    

DOI:10.1002/psc.62

出版商:John Wiley&Sons, Ltd.    

年代:1996

数据来源: WILEY

ISSN:1075-2617    

DOI:10.1002/psc.310020301

出版商:John Wiley&Sons, Ltd.    

年代:1996

数据来源: WILEY