1m8r
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Crystal Structures of Cadmium-binding Acidic Phospholipase A2 from the Venom of Agkistrodon halys pallas at 1.9 Resolution (crystal grown at pH 7.4)
OverviewOverview
Phospholipase A(2) coordinates Ca(2+) ion through three carbonyl oxygen, atoms of residues 28, 30, and 32, two carboxyl oxygen atoms of residue, Asp49, and two (or one) water molecules, forming seven (or six) coordinate, geometry of Ca(2+) ligands. Two crystal structures of cadmium-binding, acidic phospholipase A(2) from the venom of Agkistrodon halys Pallas, (i.e., Agkistrodon blomhoffii brevicaudus) at different pH values (5.9 and, 7.4) were determined to 1.9A resolution by the isomorphous difference, Fourier method. The well-refined structures revealed that a Cd(2+) ion, occupied the position expected for a Ca(2+) ion, and that the substitution, of Cd(2+) for Ca(2+) resulted in detectable changes in the metal-binding, region: one of the carboxyl oxygen atoms from residue Asp49 was farther, from the metal ion while the other one was closer and there were no water, molecules coordinating to the metal ion. Thus the Cd(2+)-binding region, appears to have four coordinating oxygen ligands. The cadmium binding to, the enzyme induced no other significant conformational change in the, enzyme molecule elsewhere. The mechanism for divalent cadmium cation to, support substrate binding but not catalysis is discussed.
About this StructureAbout this Structure
1M8R is a Single protein structure of sequence from Gloydius halys with CD and BU1 as ligands. Active as Phospholipase A(2), with EC number 3.1.1.4 Full crystallographic information is available from OCA.
ReferenceReference
Structures of cadmium-binding acidic phospholipase A2 from the venom of Agkistrodon halys Pallas at 1.9A resolution., Xu S, Gu L, Jiang T, Zhou Y, Lin Z, Biochem Biophys Res Commun. 2003 Jan 10;300(2):271-7. PMID:12504079
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