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Publication Abstract from PubMed

Crystal structures of the active-site mutants D99A and H48Q and the calcium-loop mutant D49E of bovine phospholipase A2 have been determined at around 1.9 A resolution. The D99A mutant is isomorphous to the orthorhombic recombinant enzyme, space group P212121. The H48Q and the calcium-loop mutant D49E are isomorphous to the trigonal recombinant enzyme, space group P3121. 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.

Structures of the catalytic site mutants D99A and H48Q and the calcium-loop mutant D49E of phospholipase A2.,Sekar K, Biswas R, Li Y, Tsai M, Sundaralingam M Acta Crystallogr D Biol Crystallogr. 1999 Feb;55(Pt 2):443-7. PMID:10089353^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.