摘要:

AbstractThe review addresses the functional and structural properties of the two series of chalcogen analogues of amino acids in peptides and proteins, the methionine and the serine/cysteine series, and discusses the synthesis of the related selenium/tellurium analogues as well as their use in peptide synthesis and protein expression. Advances in synthetic methodologies and recombinant technologies and their combined applications in native and expressed protein ligation allows the isomorphous character of selenium‐ and tellurium‐containing amino acids to be exploited for production of heavy metal mutants of proteins and thus to facilitate the phasing problem in x‐ray crystallography. In addition, selenocysteine has been recognized as an ideal tool for the production of selenoenzymes with new catalytic activities. Moreover, the fully isomorphous character of disulfide replacement with diselenide is well suited to increase the robustness of cystine frameworks in cystine‐rich peptides and proteins and for thede novodesign of even non‐native cystine frameworks by exploiting the highly negative redox potential of selenols. Copyright © 2005 European Peptide Society and John Wiley

ISSN:1075-2617    

DOI:10.1002/psc.654

出版商:John Wiley&Sons, Ltd.    

年代:2005

数据来源: WILEY

摘要:

AbstractIn this paper, theN‐terminus of glycoprotein‐41, the HIV‐1 fusion peptide, was studied by molecular dynamics simulations in an explicit sodium dodecyl sulfate micelle. The simulation provides a detailed picture of the equilibrium structure and peptide stability as it interacts with the micelle. The equilibrium location of the peptide shows the peptide at the surface of the micelle with hydrophobic residues interacting with the micelle's core. At equilibrium, the peptide adopts an α‐helical structure from residues 5–16 and a type‐1 β‐turn from 17–20 with the other residues exhibiting more flexible conformations. The primary hydrophobic interactions with the micelle are from the leucine and phenylalanine residues (Leu‐7, Phe‐8, Leu‐9, Phe‐11, Leu‐12) while the alanine and glycine residues (Ala‐1, Gly‐3, Gly‐5, Ala‐6, Gly‐10, Gly‐13, Ala‐14, Ala‐15, Gly‐16, Gly‐10, Ala‐21) interact favorably with water molecules. The results suggest that Phe‐8, part of the highly conserved FLG motif of the fusion peptide, plays a key role in the interaction of the peptide with membranes. Our simulations corroborate experimental investigations of the fusion peptide in SDS micelles, providing a high‐resolution picture that explains the experimental findings. Copyright ©

ISSN:1075-2617    

DOI:10.1002/psc.623

出版商:John Wiley&Sons, Ltd.    

年代:2005

数据来源: WILEY

摘要:

AbstractA procedure is presented for the automatic determination of the amino acid sequence of peptides by processing data obtained from mass spectrometry analysis. This is a basic and relevant problem in the field of proteomics. Furthermore, it has an even higher conceptual and applicative interest in peptide research, as well as in other connected fields. The analysis does not rely on known protein databases, but on the computation of all amino acid sequences compatible with the given spectral data. By formulating a mathematical model for such combinatorial problems, the structural limitations of known methods are overcome, and efficient solution algorithms can be developed. The results are very encouraging both from the accuracy and computational points of view. Copyright © 2004 European Peptide Society and John Wiley&Sons, Ltd

ISSN:1075-2617    

DOI:10.1002/psc.595

出版商:John Wiley&Sons, Ltd.    

年代:2005

数据来源: WILEY

摘要:

AbstractN‐Acetyl‐(E)‐dehydrophenylalanineN′‐methylamide [Ac‐(E)‐ΔPhe‐NHMe], one of a few representative (E)‐α,β‐dehydroamino acids, was studied by FTIR in dichloromethane and acetonitrile. To support spectroscopic interpretations and to gain some deeper insight into the Ac‐(E)‐ΔPhe‐NHMe molecule, the Ramachandran potential energy surface was calculated by the B3LYP/6‐31G*//HF/3‐21G method and the conformers localized were fully optimized at the B3LYP/6‐31 + G** level. The spectra and calculations were compared with those of the related molecules Ac‐ΔAla‐NHMe and Ac‐(Z)‐ΔPhe‐NHMe. The title compound assumes two conformational states in equilibrium in dichloromethane solution with a predominance of the extended conformer E. The Ac‐(E)‐ΔPhe‐NHMe spectrum is like that of Ac‐ΔAla‐NHMe, particularly in the region of bands AI and AII, and unlike that of Ac‐(Z)‐ΔPhe‐NHMe. The positions of bands AI and II together with the νs(N1H1) band proves that the conformers E of both ΔAla and (E)‐ΔPhe compounds are stabilized by the quite strong C5hydrogen bonds N1H1·O2. The same conclusion is drawn from the Ramachandran diagrams. The conformers E of both compounds are placed in the global minima and the gaps in energy order between them and the second conformer are large. The conformers E of ΔAla and (E)‐ΔPhe, apart from the N1H1·O2hydrogen bond, show the CβH·O1interaction, and Ac‐(E)‐ΔPhe‐NHMe displays the NH/π interaction with the N2H2projecting in the first carbon atom of the phenyl ring. The C5hydrogen bond is stronger in (E)‐ΔPhe than that in the ΔAla compound. This is in agreement with interactions found in the calculated structures and can be explained by the influence of the phenyl ring in position (E). In acetonitrile, the molecule of Ac‐(E)‐ΔPhe‐NHMe loses its C5hydrogen bond and becomes unfolded, whereas that of Ac‐ΔAla‐NHMe does not vary practically. Adopting conformation E in a non‐polar solvent seems t

ISSN:1075-2617    

DOI:10.1002/psc.601

出版商:John Wiley&Sons, Ltd.    

年代:2005

数据来源: WILEY