The crystal structure of the amino-terminal pentapeptide of suzukacillin. Occurrence of a four-fold peptide helix

Francis, Athappilly K and Mohammed, Iqbal and Balaram, Padmanabhan and Vijayan, Mamannamana (1982) The crystal structure of the amino-terminal pentapeptide of suzukacillin. Occurrence of a four-fold peptide helix. In: Perkin Transactions 2 (10). pp. 1235-1239.

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Abstract

The monohydrate of the protected amino-terminal pentapeptide of suzukacillin, t-butoxycarbonyl--aminoisobutyryl-L-prolyl-L-valyl--aminoisobutyryl-L-valine methyl ester, C29H51N5O8, crystallizes in the orthorhombic space group P212121 with a= 10.192, b= 10.440, c= 32.959 Å, and Z= 4. The structure has been solved by direct methods and refined to an R value of 0.101 for 1 827 observed reflections. The molecule exists as a four-fold helix with a pitch of 5.58 Å. The helix is stabilised by N–H O hydrogen bonds, two of the 51 type (corresponding to the -helix) and the third of the 41 type (310 helix). The carbonyl oxygen of the amino-protecting group accepts two hydrogen bonds, one each from the amide NH groups of the third (41) and fourth (51) residues. The remaining 51 hydrogen bond is between the two terminal residues. The lone water molecule in the structure is hydrogen bonded to carbonyl oxygens of the prolyl residue in one molecule and the non-terminal valyl residue in a symmetry-related molecule.

Item Type:	Journal Article
Publication:	Perkin Transactions 2
Publisher:	Royal Society of Chemistry
Additional Information:	Copyright of this article belongs to Royal Society of Chemistry.
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	30 May 2009 06:26
Last Modified:	19 Sep 2010 05:33
URI:	http://eprints.iisc.ac.in/id/eprint/20446

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