Conformational transitions in a Pro-Pro peptide on dissolution of single crystals

Balaram, Hemalatha ; Venkataram Prasad, B. V. ; Balaram, P. (1982) Conformational transitions in a Pro-Pro peptide on dissolution of single crystals Biochemical and Biophysical Research Communications, 109 (3). pp. 825-831. ISSN 0006-291X

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Official URL: http://www.sciencedirect.com/science/article/pii/0...

Related URL: http://dx.doi.org/10.1016/0006-291X(82)92014-9

Abstract

The peptide t-butyloxycarbonyl-α-aminoisobutyryl-L-prolyl-L-prolyl-N-methylamide has been shown to adopt an extended structure in the solid state. The Pro-Pro segment occurs in the poly-proline II conformation. On dissolution of single crystals at ~233°K, a single species corresponding to the all trans peptide backbone is observed by 270 MHz 1H NMR. On warming, trans to cis isomerization about the Pro-Pro bond is facilitated. Both cis' (ψ~-50°) and trans' (ψ~ 130°) rotamers about the Pro3 Cα-CO bond are detectable in the Pro-Pro cis conformer, at low temperature. These observations demonstrate unambiguously the large differences in the solid state and solution conformations of a Pro-Pro sequence.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
ID Code:91365
Deposited On:21 May 2012 07:07
Last Modified:13 Jul 2012 11:09

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