Structures of the catalytic site mutants D99A and H48Q and the calcium-loop mutant D49E of phospholipase A(2)

Sekar, K and Li, Y and Tsai, MD and Sundaralingam, M (1999) Structures of the catalytic site mutants D99A and H48Q and the calcium-loop mutant D49E of phospholipase A(2). In: Acta Crystallographica Section D, 55 (part 2). 443-447 .

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Abstract

Crystal structures of the active-site mutants D99A and H48Q and the calcium-loop mutant D49E of bovine phospholipase A(2) have been determined at around 1.9 Angstrom resolution. The D99A mutant is isomorphous to the orthorhombic recombinant enzyme, space group P2(1)2(1)2(1), The H48Q and the calcium-loop mutant D49E are isomorphous to the trigonal recombinant enzyme, space group P3(1)21, The two active-site mutants show no major structural perturbations. The structural water is absent in D99A and, therefore, the hydrogen-bonding scheme is changed. In H48Q, the catalytic water is present and hydrogen bonded to Gln48 N, but the second water found in native His48 is absent. In the calcium-loop mutant D49E, the two water molecules forming the pentagonal bipyramid around calcium are absent and only one O atom of the Glu49 carboxylate group is coordinated to calcium, resulting in only four ligands.

Item Type:	Journal Article
Publication:	Acta Crystallographica Section D
Publisher:	International Union of Crystallography
Additional Information:	Copyright of this article belongs to International Union of Crystallography.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	30 Jun 2011 07:18
Last Modified:	30 Jun 2011 07:18
URI:	http://eprints.iisc.ac.in/id/eprint/38805

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