Two-Dimensional1H NMR Study of a Tetradecapeptide with the Consensus Sequence Arg5-Asp-Val-Arg-Gly9: Structural Effects of the Outside Substitution Ser12by Ala12
| Autor: | Francois-Regis Chalaoux, Jacques Riand, Anne-Marie Leseney, Daniel Baron |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Alanine
Magnetic Resonance Spectroscopy Molecular model Protein Conformation Chemistry Molecular Sequence Data General Medicine Nuclear magnetic resonance spectroscopy Dihedral angle Random coil Crystallography Protein structure Structural Biology Consensus Sequence Proton NMR Computer Simulation Dimethyl Sulfoxide Amino Acid Sequence Peptides Oligopeptides Molecular Biology Two-dimensional nuclear magnetic resonance spectroscopy Conformational isomerism |
| Zdroj: | Journal of Biomolecular Structure and Dynamics. 12:993-1008 |
| ISSN: | 1538-0254 0739-1102 |
| DOI: | 10.1080/07391102.1995.10508792 |
| Popis: | Conformation of a tetradecapeptide with a RXVRG consensus sequence, Arg5-Asp-Val-Arg-Gly9, found in several precursors of antibacterian peptides, was investigated in dimethylsulfoxide solution by proton NMR spectroscopy. Complete resonance assignments and conformational parameters were obtained through correlated (COSY) and nuclear Overhauser (NOESY) techniques. The 3J(alpha H, beta H) coupling constants and the intramolecular NOE, NH...beta H, were used to analyse the conformers around the C alpha-C beta bond and, in four cases, to obtain stereospecific assignments. Use of restraints derived from NOE connectivities and 3J(NH, alpha H) coupling constants allows the determination of a range of phi and psi dihedral angles for all the residues in the sequence. The present NMR results provide favourable evidence for the formation of two bends in the consensus sequence of the tetradecapeptide. The first one has most of the features of a Glu4-Val7 beta-turn (low temperature coefficient of the Val7NH chemical shift, Arg5 alpha H...Val7NH and Asp6NH...Val7NH NOE correlations). The second one exhibits only the Asp6 alpha H...Arg7NH and Val7NH...Arg8NH NOE interactions. These consensus sequence organizations proposed were confirmed by molecular modeling based on low potential energy structure on the [4-9] fragment with high agreement of NOE data. Overall, the substitution of Ser12 by Ala12 shifts the conformation of the hydrophobic moiety [10-14] towards a quite random coil structure in this fragment and strongly destabilizes the folded structures of the consensus domain where only one NH (Val7) is solvent-shielded opposed to three (Asp6 to Arg8) in the [Ser12] tetradecapeptide. These conformational changes could be related to the processing enzyme activities on these model oligopeptides. |
| Databáze: | OpenAIRE |
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