1y6p
From Proteopedia
|
Crystal structure of disulfide engineered porcine pancratic phospholipase a2 to group-x isozyme
Overview
The family of secreted 14 kDa phospholipase A(2) (PLA2) enzymes have a, common motif for the catalytic site but differ in their disulfide, architecture. The functional significance of such structural changes has, been analyzed by comparing the kinetic and spectroscopic properties of a, series of disulfide mutants engineered into the sequence of pig pancreatic, IB PLA2 to resemble the mammalian paralogues of the PLA2 family [Janssen, et al. (1999) Eur. J. Biochem. 261, 197-207, 1999]. We report a detailed, comparison of the functional parameters of pig iso-PLA2, as well as, several of the human homologues, with these disulfide engineered mutants, of pig IB PLA2. The crystal structure of the ligand free and the active, site inhibitor-MJ33 bound forms of PLA2 engineered to have the disulfide, bonding pattern of group-X (eng-X) are also reported and compared with the, structure of group-IB and human group-X PLA2. The engineered mutants show, noticeable functional differences that are rationalized in terms of, spectroscopic properties and the differences detected in the crystal, structure of eng-X. A major difference between the eng-mutants is in the, calcium binding to the enzyme in the aqueous phase, which also influences, the binding of the active site directed ligands. We suggest that the, disulfide architecture of the PLA2 paralogues has a marginal influence on, interface binding. In this comparison, the modest differences observed in, the interfacial kinetics are attributed to the changes in the side chain, residues. This in turn influences the coupling of the catalytic cycle to, the calcium binding and the interfacial binding event.
About this Structure
1Y6P is a Single protein structure of sequence from Sus scrofa with CA and CL as ligands. Active as Phospholipase A(2), with EC number 3.1.1.4 Full crystallographic information is available from OCA.
Reference
Kinetic and structural properties of disulfide engineered phospholipase A2: insight into the role of disulfide bonding patterns., Yu BZ, Pan YH, Janssen MJ, Bahnson BJ, Jain MK, Biochemistry. 2005 Mar 8;44(9):3369-79. PMID:15736947
Page seeded by OCA on Wed Nov 21 06:36:26 2007
