2B96 image
Entry Detail
PDB ID:
2B96
Keywords:
Title:
Third Calcium ion found in an inhibitor bound phospholipase A2
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2005-10-11
Release Date:
2006-03-28
Method Details:
Experimental Method:
Resolution:
1.70 Å
R-Value Free:
0.22
R-Value Work:
0.20
Space Group:
P 31 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Phospholipase A2
Mutations:K53M, K56M, K121M
Chain IDs:A
Chain Length:123
Number of Molecules:1
Biological Source:Bos taurus
Primary Citation

Abstact

The lipolytic enzyme phospholipase A2 plays a crucial role in lipid metabolism and catalyzes hydrolysis of the fatty-acid ester bond at the sn-2 position of phospholipids. Here, the crystal structure (1.7 A resolution) of the triple mutant (K53,56,121M) of bovine pancreatic phospholipase A2 complexed with an organic molecule, p-methoxybenzoic acid (anisic acid), is reported. Residues 60-70 (the surface-loop residues) are ordered and adopt conformations which are different from those normally found in structures in which a second calcium ion is present. It is interesting to note that for the first time a third calcium ion has been identified. In addition, four Tris (2-amino-2-hydroxymethyl-1,3-propanediol) molecules were located. It is believed that one of the Tris molecules plays a role in clamping the third calcium ion and that another is involved in controlling the dynamics of the surface loop through hydrogen bonds.

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Primary Citation of related structures