Download MendeleyThird Calcium ion found in an inhibitor bound phospholipase A2
Sekar, K., Gayathri, D., Velmurugan, D., Jeyakanthan, J., Yamane, T., Poi, M.J., Tsai, M.D.(2006) Acta Crystallogr D Biol Crystallogr 62: 392-397
- PubMed: 16552140
- DOI: https://doi.org/10.1107/S0907444906001612
- Primary Citation of Related Structures:
2B96 - PubMed Abstract:
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.
Organizational Affiliation:
Bioinformatics Centre, Indian Institute of Science, Bangalore 560 012, India. sekar@physics.iisc.ernet.in
