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X-ray studies on crystalline complexes involving amino acids and peptides. XXXV. Invariance and variability in amino acid aggregation in the complexes of maleic acid with L-histidine and L-lysine

Pratap, JV and Ravishankar, R and Vijayan, M (2000) X-ray studies on crystalline complexes involving amino acids and peptides. XXXV. Invariance and variability in amino acid aggregation in the complexes of maleic acid with L-histidine and L-lysine. In: Acta Crystallographica Section B, 56 . pp. 690-696.

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Abstract

The crystal structures of complexes of maleic acid with l-histidine and l-lysine have been determined. The two crystallographically independent amino acid molecules in the l-histidine complex have different closed conformations, while the lysine molecule in its complex has the most favourable conformation sterically with an all-trans sidechain trans to the -carboxylate group. The maleic acid molecules exist as semimaleate ions of similar conformation and contain a symmetric O H O hydrogen bond. Amino acid cations and semimaleate anions aggregate into alternate layers in both the structures. The arrangement of molecules in the histidine layer in l histidine semi- maleate is closer to that in the crystals of the free amino acid than in other l-histidine complexes. On the other hand, the arrangement of lysine molecules in its semi-maleate complex is different from any observed so far. However, the well established characteristic interaction patterns involving amino and carboxylate groups still play a major role in holding the molecules together in the crystal of the complex.

Item Type: Journal Article
Additional Information: The copyright belongs to International Union of Crystallography
Keywords: crystalline complexes;amino acids;peptides;maleic acid;l histidine;l lysine
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Date Deposited: 30 Aug 2004
Last Modified: 19 Sep 2010 04:14
URI: http://eprints.iisc.ernet.in/id/eprint/1371

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