The-effect of capper(II) ions on the probabilities of existence of the four detectable conformers of the tetrapeptide Tyr-Pro-Phe-Pro (beta -casomorphin 4) in [H-2(6)]DMSO was investigated by H-1 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)-H alpha 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.
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|Titolo:||Metal ion effects on cis/trans isomerization of proline residues in short chain peptides in solution|
|Citazione:||Gaggelli, E., N., D., Gaggelli, N., & Valensin, G. (2001). Metal ion effects on cis/trans isomerization of proline residues in short chain peptides in solution. CHEMBIOCHEM, 2, 524-529.|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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