Saraswathi, NT and Vijayan, M (2002) X-ray studies on crystalline complexes involving amino acids and peptides. XXXIX. crystal structures of malonic acid complexes of DL- and L-histidine. preservation of aggregation pattern on reversal of chirality. In: Acta Crystallographica Section B, 58 (4). pp. 734-739.
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The malonic acid complexes of DL- and L-histidine are made up of zwitterionic positively charged histidinium ions and semimalonate (hydrogen malonate) ions. They crystallise in space groups P2(1)/n and P2(1), respectively, with nearly the same unit-cell parameters. The molecules aggregate in the two complexes in a remarkably similar manner. The two sets of crystallographically independent molecules are related by a pseudo-glide plane. This pseudo-symmetry is almost exact except in the case of the alpha-carboxylate group and, to some extent, the alpha-C and the alpha-N atoms. Preservation of the aggregation pattern to such an extent on the reversal of chirality of half the amino-acid molecules is observed for the first time in amino-acid complexes. This is achieved at the cost of considerable conformational strain in one of the two histidinium ions in the L-histidine complex.
|Item Type:||Journal Article|
|Additional Information:||Copyright belongs to International Union of Crystallography.|
|Department/Centre:||Division of Biological Sciences > Molecular Biophysics Unit|
|Date Deposited:||27 Sep 2004|
|Last Modified:||16 Jan 2012 05:32|
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