1psh
From Proteopedia
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CRYSTAL STRUCTURE OF PHOSPHOLIPASE A2 FROM INDIAN COBRA REVEALS A TRIMERIC ASSOCIATION
Overview
Phospholipase A2 (PLA2) from Indian cobra venom (Naja naja naja) was, crystallized from ethanol in space group P4(3)2(1)2 in the presence of, Ca2+. The x-ray crystal structure was determined to 2.3-A resolution by, molecular replacement techniques using a theoretical model constructed, from homologous segments of the bovine pancreatic, porcine pancreatic, and, rattlesnake venom crystal structures. The structure was refined to an R, value of 0.174 for 17,542 reflections between 6.0- and 2.3-A resolution (F, > 2 sigma), including 148 water molecules. The 119-amino acid enzyme has, an overall architecture strikingly similar to the other known PLA2, structures with regions implicated in catalysis showing the greatest, structural conservation. Unexpectedly, three monomers were found to occupy, the asymmetric unit and are oriented with their catalytic sites facing the, pseudo-threefold axis with approximately 15% of the solvent accessible, surface of each monomer buried in trimer contacts. The majority of the, interactions at the subunit interfaces are made by residues unique to PLA2, sequences from cobra and krait venoms. The possible relevance of this, unique trimeric structure is considered.
About this Structure
1PSH is a Single protein structure of sequence from Naja naja with CA as ligand. Active as Phospholipase A(2), with EC number 3.1.1.4 Full crystallographic information is available from OCA.
Reference
Crystal structure of phospholipase A2 from Indian cobra reveals a trimeric association., Fremont DH, Anderson DH, Wilson IA, Dennis EA, Xuong NH, Proc Natl Acad Sci U S A. 1993 Jan 1;90(1):342-6. PMID:8419939
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