Conformational variability of Gly-Gly segments in peptides: A comparison of the crystal structures of an acyclic pentapeptide and an octapeptide

Datta, Saumen and Shamala, N and Banerjee, Arindam and Balaram, P (1997) Conformational variability of Gly-Gly segments in peptides: A comparison of the crystal structures of an acyclic pentapeptide and an octapeptide. In: Biopolymers, 41 . pp. 331-336.

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Abstract

The crystal structure of an acyclic pentapeptide, Boc-Gly-Gly-Leu-Aib-Val-OMe, reveals an extended conformation for the Gly-Gly segment, in contrast to the helical conformation determined earlier in the octapeptide Boc-Leu-Aib-Val-Gly-Gly-Leu-Aib-Val-OMe [I. L. Karle, A. Banerjee, S. Bhattacharjya, and P. Balaram [1996] Biopolymers, Vol. 38, pp. 515-526). The pentapeptide crystallizes in space group P21 with one molecule in the asymmetric unit. The cell parameters are: a = 10.979(2) Å, b = 9.625(2) Å, c = 14.141(2) Å, and = 96.93(1)°, R = 6.7% for 2501 reflections (I > 3 (I)). The Gly-Gly segment is extended ( 1 = -92°, 1 = -133°, 2 = 140°, 2 = 170°), while the Leu-Aib segment adopts a type II -turn conformation ( 3 = -61°, 3 = 130°, 4 = 71°, 4 = 6°). The observed conformation for the pentapeptide permits rationalization of a structural transition observed for the octapeptide in solution. An analysis of Gly-Gly segments in peptide crystal structures shows a preference for either -turn or extended conformations.

Item Type:	Journal Article
Publication:	Biopolymers
Publisher:	John Wiley & Sons, Inc.
Additional Information:	The copyright of this article belongs to John Wiley & Sons, Inc.
Keywords:	acyclic pentapeptide;Gly-Gly segments
Department/Centre:	Division of Physical & Mathematical Sciences > Physics Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	02 Jun 2004
Last Modified:	19 Sep 2010 04:12
URI:	http://eprints.iisc.ac.in/id/eprint/339

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