Pratap, J. V. ; Ravishankar, R. ; 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 Acta Crystallographica Section B, 56 . pp. 690-696. ISSN 0108-7681
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Official URL: http://scripts.iucr.org/cgi-bin/paper?ha0195
Related URL: http://dx.doi.org/10.1107/S0108768100002202
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 α-carboxylate group. The maleic acid molecules exist as semi-maleate ions of similar conformation and contain a symmetric O...H...O hydrogen bond. Amino acid cations and semi-maleate 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: | Article |
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Source: | Copyright of this article belongs to International Union of Crystallography. |
Keywords: | Amino Acids; Peptides; Aggregation; Histidine and Lysine Complexes |
ID Code: | 53864 |
Deposited On: | 10 Aug 2011 09:31 |
Last Modified: | 10 Aug 2011 09:31 |
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