Peptide Design: Crystal Structure of a Helical Peptide Module Attached to a Potentially Nonhelical Amino Terminal Segment

Karle, Isabella L and Rao, Balaji R and Kaul, Ramesh and Prasad, Sudhanand and Balaram, P (1996) Peptide Design: Crystal Structure of a Helical Peptide Module Attached to a Potentially Nonhelical Amino Terminal Segment. In: Biopolymers, 39 (1). pp. 75-83.

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Abstract

The pept ide Boc- Gly- Dpg- Gly- Val-A la- Leu-A ib- Val-A la- Leu- 0 Me has been designed to examine the structural consequences of placing a short segment with a low helix propensity at the amino terminus of a helical heptapeptide module. The Gl-v-Dpg-Gly segment is a potential connecting element in the synthetic construction of a helix-linker-helix motif. Crystal parameters for the peptide are P21, a = 8.651(3) Å, b = 46.826(13) Å, c = 16.245 Å, beta = 90.13(3)*, Z = 4: 2 independent molecules/asymmetric unit. The structure reveals almost identical conformations,for the two independent molecules. The backbone is completely helical for residues 2-9, with one 4 - 1 hydrogen bond and six 5 - 1 hydrogen bonds. The alpha,alpha-di-n-prop-vlglycine residue adopts a helical conjormation. Gly( I ) adopts an extended conformation resulting in a nonhelical N-terminus, with the Boc group swinging away,from the helix. The lateral association of helices in the b axis direction is unusual in that the helix axes are directed up or down (parallel or antiparallel) by pairs, etc.

Item Type:	Journal Article
Publication:	Biopolymers
Publisher:	John Wiley & Sons, Inc
Additional Information:	Copyright for this article belongs to John Wiley & Sons, Inc.
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	19 Jan 2007
Last Modified:	19 Sep 2010 04:17
URI:	http://eprints.iisc.ac.in/id/eprint/2257

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