摘要:

AbstractCuI‐catalyzed azide‐alkyne 1,3‐dipolar Huisgen's cycloaddition (CuAAC) is a click reaction that has drawn a lot of attention, in general, and in the field of peptide and protein sciences, in particular. Among several reported applications, the preparation of novel heterodetic cyclopeptides by an intramolecular side chain‐to‐side chain CuAAC, forming a 1,4‐disubstituted[1,2,3]triazolyl‐containing bridge, is of great interest. Herein, we provide a detailed protocol for the syntheses of model heterodetic cyclopeptides as a prototypical intramolecular CuAAC, using as a model a sequence derived from parathyroid hormone‐related protein. Copyright © 2009 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.1141

出版商:John Wiley&Sons, Ltd.    

年代:2009

数据来源: WILEY

摘要:

AbstractPolyproline II (PPII) helix is an extended secondary structure present in a number of proteins. PPII‐containing sequences mediate specific protein–protein interactions with partners containing appropriate cognate domains called PPII‐recognizing domains (PRDs) and are involved in the activation of intracellular signaling pathways. Thus, the identification of PPII structures in proteins is of great interest, not only to explore molecular and physiological mechanisms, but also to elaborate new potential drugs. By revisiting X‐ray crystal structures of liganded α‐type human estrogen receptor (ERα), we have identified an 11‐residue PPII‐helical sequence (D321AEPPILYSEY331) in the ligand‐binding domain of the receptor. The data recorded by far‐ultraviolet circular dichroism (far‐UV CD), vibrational Raman optical activity (ROA) and differential scanning calorimetry (DSC) show that the corresponding peptide (Ac‐DAEPPILYSEY‐NH2) is particularly well structured in PPII, with the same proportion of PPII as observed from X‐ray structures (∼85%). In addition, studies carried out on ERα‐negative Evsa‐T breast cancer cells transiently co‐transfected with a pcDNA3‐ERα plasmid and a Vit‐tk‐Luc reporter gene revealed that the peptide antagonizes the estradiol‐induced transcription providing perspectives for researching new molecules with antagonistic properties. Copyright © 2009 Eur

ISSN:1075-2617    

DOI:10.1002/psc.1136

出版商:John Wiley&Sons, Ltd.    

年代:2009

数据来源: WILEY

摘要:

AbstractDehydroamino acids are non‐coded amino acids that offer unique conformational properties. Dehydrophenylalanine (ΔPhe) is most commonly used to modify bioactive peptides to constrain the topography of the phenyl ring in the side chain, which commonly serves as a pharmacophore. The Ramachandran maps (in the gas phase and in CHCl3mimicking environments) of ΔPhe analogues with methyl groups at the β position of the side chain as well as at theC‐terminal amide were calculated using the B3LYP/6‐31 + G** method. Unexpectedly, β‐methylation alone results in an increase of conformational freedom of the affected ΔPhe residue. However, further modification by introducing an additional methyl group atC‐terminal methyl amide results in a steric crowding that fixes the torsion angle ψ of all conformers to the value 123°, regardless of theZorEposition of the phenyl ring. The number of conformers is reduced and the accessible conformational space of the residues is very limited. In particular, (Z)‐Δ(βMe)Phe with the tertiaryC‐terminal amide can be classified as the amino acid derivative that has a single conformational state as it seems to adopt only the β conformation. Copyright © 2009 European Peptide Society

ISSN:1075-2617    

DOI:10.1002/psc.1137

出版商:John Wiley&Sons, Ltd.    

年代:2009

数据来源: WILEY

摘要:

AbstractThe electrophilic reactivity of Boc‐DKPs has been studied. Thanks to Boc activation, the opening ability of carbonyl lactam groups is enhanced. According to experimental conditions, this enabled the synthesis of Boc‐amino acid derivatives or original dipeptides via a regioselective and sequential way. Copyright © 2009 European Peptide Society and John Wiley&Sons,

ISSN:1075-2617    

DOI:10.1002/psc.1139

出版商:John Wiley&Sons, Ltd.    

年代:2009

数据来源: WILEY

摘要:

AbstractThe 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 ETAor ETBis 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 described. As a result, we could improve the selectivity of BQ3020 about 10‐fold by a single amino acid substitution, validating our hypothesis for ligand selectivity caused by different entrances to the receptors' transmembrane binding sites. A narrow tunnel shape in ETAis restrictive for a selected group of peptide ligands'N‐termini, whereas a broad funnel‐shaped entrance in ETBaccepts a variety of different shapes and properties of ligands. Copyright © 2009 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/psc.1146

出版商:John Wiley&Sons, Ltd.    

年代:2009

数据来源: WILEY

摘要:

AbstractAntimicrobial peptides are important components of the host innate immune responses by exerting broad‐spectrum microbicidal activity against pathogenic microbes.Cy‐AMP1 found in the cycad (Cycas revoluta) seeds has chitin‐binding ability, and the chitin‐binding domain was conserved in knottin‐type and hevein‐type antimicrobial peptides. The recombinantCy‐AMP1 was expressed inEscherichia coliand purified to study the role of chitin‐binding domain. The mutants ofCy‐AMP1 lost chitin‐binding ability completely, and its antifungal activity was markedly decreased in comparison with nativeCy‐AMP1. However, the antimicrobial activities of the mutant peptides are nearly identical to that of native one. It was suggested that the chitin‐binding domain plays an essential role in antifungal, but not antimicrobial, activity ofCy‐AMP1. Copyright © 2009 European Peptide Societ

ISSN:1075-2617    

DOI:10.1002/psc.1147

出版商:John Wiley&Sons, Ltd.    

年代:2009

数据来源: WILEY