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Metal ion effects on the cis/trans isomerization equilibrium of proline in short-chain peptides: a solution NMR study.
- Source :
-
Chembiochem : a European journal of chemical biology [Chembiochem] 2001 Aug 03; Vol. 2 (7-8), pp. 524-9. - Publication Year :
- 2001
-
Abstract
- The effect of copper(II) ions on the probabilities of existence of the four detectable conformers of the tetrapeptide Tyr-Pro-Phe-Pro (beta-casomorphin 4) in [2H6]DMSO was investigated by 1H NMR spectroscopy. Integration of the Phe-NH signals provided the relative populations in the free state as tt/tc/ct/cc=28:34:29:9 at 293 K (c=cis, t=trans). Copper(II) was shown to bind to all four isomers, yielding complexes with two different structures, depending on the conformation of Pro(2). The interpretation of paramagnetic relaxation rates of Pro(2)-Halpha signals provided the corresponding isomeric probabilities in the metal-bound state as 13:36:20:31. The observed stabilization of the conformation with the lowest probability of existence (cc) may be relevant for the biological role of copper and other metal ions.
Details
- Language :
- English
- ISSN :
- 1439-4227
- Volume :
- 2
- Issue :
- 7-8
- Database :
- MEDLINE
- Journal :
- Chembiochem : a European journal of chemical biology
- Publication Type :
- Academic Journal
- Accession number :
- 11828485
- Full Text :
- https://doi.org/10.1002/1439-7633(20010803)2:7/8<524::AID-CBIC524>3.0.CO;2-P