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PDBsum entry 1psh
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Carboxylic ester hydrolase
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PDB id
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1psh
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Crystal structure of phospholipase a2 from indian cobra reveals a trimeric association.
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Authors
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D.H.Fremont,
D.H.Anderson,
I.A.Wilson,
E.A.Dennis,
N.H.Xuong.
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Ref.
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Proc Natl Acad Sci U S A, 1993,
90,
342-346.
[DOI no: ]
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PubMed id
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Abstract
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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.
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