Conformational analysis of the tetrapeptide Pro-D-Phe-Pro-Gly in aqueous solution
| Autor: | Wolfgang Brandt, Gunter Fischer, B. Hartrodt, M. Wahab, Erich Kleinpeter, H. Schinke, Dieter Ströhl, D. Hübner |
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| Rok vydání: | 1991 |
| Předmět: |
Magnetic Resonance Spectroscopy
Tetrapeptide Protein Conformation Stereochemistry Chemistry Chemical shift Biophysics Cell Biology Hydrogen-Ion Concentration Carbon-13 NMR Biochemistry Peptide Fragments Cis trans isomerization Solutions Isomerism Thermodynamics Peptide bond Endorphins Molecular Biology Isomerization Conformational isomerism Cis–trans isomerism |
| Zdroj: | Biochemical and Biophysical Research Communications. 177:271-278 |
| ISSN: | 0006-291X |
| DOI: | 10.1016/0006-291x(91)91978-l |
| Popis: | Conformational investigations of the tetrapeptide Pro-D-Phe-Pro-Gly in water solution were carried out by 1 H and 13 C NMR spectroscopy. The internal proline residue allows for the possibility of cis/trans isomerization about the D-Phe-Pro peptide bond resulting in two conformational isomers. The major isomer was identified as the trans isomer. The pH-dependence of the cis/trans equilibrium supports an additional stabilisation of the trans isomer by an intramolecular ionic interaction between the amino- and carboxy-terminus in the zwitterionic state. Based on 13 C spinlattice relaxation times(T 1 ), different pyrrolidine ring conformations of Pro 1 and Pro 3 could be determined. By combination of several NMR data ( vicinal coupling constants 3 J Na , temperature dependence of the NH chemical shifts, differences in the chemical shifts between the β and γ carbons of the proline residues) and energy minimization calculations, a type II' β-turn should contribute considerably to the overall structure of the trans isomer. |
| Databáze: | OpenAIRE |
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