Parallel zippers formed by \alpha-helical peptide columns in crystals of Boc-Aib-Glu(OBzl)-Leu-Aib-Ala-Leu-Aib-Ala-Lys(Z)-Aib-OMe

Karle, Isabella L and Flippen-Anderson, Judith L and Uma, Kuchibhotla and Balaram, Padmanabhan (1990) Parallel zippers formed by \alpha-helical peptide columns in crystals of Boc-Aib-Glu(OBzl)-Leu-Aib-Ala-Leu-Aib-Ala-Lys(Z)-Aib-OMe. In: Proceedings of the National Academy of Sciences of the United States of America, 87 (20). pp. 7921-7925.

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Abstract

The crystal structure of the decapeptide Boc-Aib-Glu(OBzl)-Leu-Aib-Ala-Leu-Aib-Ala-Lys(Z)-Aib-OMe (where Aib is -aminoisobutyryl, Boc is t-butoxycarbonyl, OBzl is benzyl ester, and Z is benzyloxycarbonyl) illustrates a parallel zipper arrangement of interacting helical peptide columns. Head-to-tail NH ··· OC hydrogen bonding extends the \alpha-helices formed by the decapeptide into long columns in the crystal. An additional NH··· OC hydrogen bond in the head-to-tail region, between the extended side chains of Glu(OBzl), residue 2 in one molecule, and Lys(Z), residue 9 in another molecule, forms a "double tooth" on the side of the column. These double teeth are repeated regularly on the helical columns with spaces of six residues between them (\approx 10 Å). The double teeth on a pair of parallel columns (all carbonyl groups pointed in the same direction) interdigitate in a zipper motif. All contacts in the zipper portion are of the van der Waals type. The peptide, with formula C66H103N11O17··&m iddot;H2O, crystallizes in space group P212121 with a = 10.677(4) Å, b = 16.452(6) Å, and c = 43.779(13) Å; overall agreement R = 10.2% for 3527 observed reflections (|F0| > 3\sigma); resolution 0.9 Å.

Item Type:	Journal Article
Publication:	Proceedings of the National Academy of Sciences of the United States of America
Publisher:	National Academy of Sciences
Additional Information:	Copyright for this article belongs to National Academy of Sciences.
Keywords:	double-toothed zipper;x-ray diffraction;helical peptide zipper;helix aggregation;peptide crystal structure
Department/Centre:	Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited:	24 Dec 2004
Last Modified:	05 Jan 2011 07:23
URI:	http://eprints.iisc.ac.in/id/eprint/2515

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