摘要:

AbstractThe human follicle‐stimulating hormone (hFSH) belongs to a family of glycoprotein hormones which contains two non‐identical subunits. This paper describes the design and synthesis of a series of synthetic hFSH constructs as putative ligands for the receptor. The design of these constructs is based on the crystal structure of hCG and molecular modelling using the program package Insight II/Discover. The designed constructs contain peptides ranging from 7 to 48 amino acid residues, disulphide bridges and glycan residues. All the synthetic peptides were synthesized by the stepwise solid‐phase method using Fmoc chemistry. Two of the synthetic peptides contain the glycosylated amino acid, Asn(GlcNAc‐GlcNAc) and both were prepared using fully protected glycosylated building blocks in the solid‐phase peptide synthesis. The disulphide bridges were formed from acetamidomethyl‐protected glycopeptides and peptides by a direct deprotection/oxidation method using thallium(III) trifluoroacetate. Mass spectroscopy and amino acid analysis were used for characterization of the synthetic hFSH glycopeptides and peptides. The synthetic hFSH constructs were tested for binding activity on FSH receptor assays but none showed improved binding properties compared with the naturally occurring hormone. It was finally demonstrated that non‐related peptides showed non‐specific binding at the same level as reported for specific peptides. © 1997 European Peptide Society and John

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199711)3:6<397::AID-PSC113>3.0.CO;2-K

出版商:John Wiley&Sons, Ltd.    

年代:1997

数据来源: WILEY

摘要:

AbstractTo understand the structural requirements for the biological activity of endothelin peptides and to develop receptor selective endothelin analogues further, the solution structure of the bicyclic 21 amino acid residue vasoactive peptide, endothelin‐1, has been determined in methanol‐d3/water using high‐resolution1H‐NMR spectroscopy. To our knowledge, this solvent system has not previously been used in NMR studies of endothelin and/or endothelin‐like peptides. Two‐dimensional DQFCOSY, TOCSY and NOESY spectra were acquired along with a series of one‐dimensional spectra. A total of 219 distance constraints and 5 angle constraints were derived from the NMR data. These were incorporated into structure calculations using distance geometry (DIANA) followed by simulated annealing and molecular dynamics. The resulting structures are characterized by an α‐helical conformation, Lys9‐His16, and residues Ser5‐Asp8form a type I β‐turn. The N‐terminal region, which was not extensively constrained by NMR data, showed no preferred conformation. The C‐terminal tail showed less extensive conformational averaging but no descriptive conformation could be observed. The results obtained in this study are in good agreement with previous proposals. ©1997 European Peptide Soci

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199711)3:6<415::AID-PSC114>3.0.CO;2-S

出版商:John Wiley&Sons, Ltd.    

年代:1997

数据来源: WILEY

摘要:

AbstractThe Nα/CαH exchange in aza‐peptides has the advantage of preserving the side chain. Bis(trichloromethyl)carbonate or triphosgene is a solid, stable phosgene substitute which retains its high reactivity. Temperature and coupling times are greatly reduced with reference to other usually recommended carbonylating agents, while purity and yield are increased. It has been used, in both liquid‐ and solid‐phase procedures, for the synthesis of various aza‐analogues of dipeptides, tripeptides and decapeptides containing the alanine, aspartic acid and asparagine aza‐residue. ©1997 European Peptide Society and John Wil

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199711)3:6<429::AID-PSC115>3.0.CO;2-C

出版商:John Wiley&Sons, Ltd.    

年代:1997

数据来源: WILEY

摘要:

AbstractUsing the Fmoc/tBu protection scheme and thep‐methoxybenzyl derivative of selenocysteine, the synthesis of related peptides in the selenol‐protected form could be optimized by operating the coupling steps in the absence of auxiliary bases and by reducing the piperidine treatment to the minimum time required for quantitative Fmoc cleavage. Under these conditions, β‐elimination of thep‐methoxybenzylselenol as the main side reaction of these syntheses, as well as epimerization of the protected selenocysteine, was largely suppressed. Conversion of the selenol‐ and thiol‐protected bis‐selenocysteine and selenocysteine, cysteine peptides into the related cyclic monomeric forms by iodine‐mediated oxidation failed since a complex mixture of compounds was produced. Cleavage of the selenoether bond with mercuric acetate was found to proceed smoothly, but displacement of the heavy metal ions by treatment with excesses of thiols or hydrogen sulphide was unsuccessful since a stable Hg2+diselenide complex was obtained. However, oxidation was achieved in good yields by the dimethylsulphoxide/trifluoroacetic acid procedure and the peptides were then used for determining the redox potential of the diselenide and selenide/sulphide bridge, respectively. © 1997 European Peptide Society and Joh

ISSN:1075-2617    

DOI:10.1002/(SICI)1099-1387(199711)3:6<442::AID-PSC122>3.0.CO;2-2

出版商:John Wiley&Sons, Ltd.    

年代:1997

数据来源: WILEY