1le7
CARBOXYLIC ESTER HYDROLASE, C 2 2 21 space group
Structural highlights
FunctionPA2GX_HUMAN PA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-phosphoglycerides. Has a powerful potency for releasing arachidonic acid from cell membrane phospholipids. Prefers phosphatidylethanolamine and phosphatidylcholine liposomes to those of phosphatidylserine. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structure of human group X (hGX) secreted phospholipase A2 (sPLA2) has been solved to a resolution of 1.97 A. As expected the protein fold is similar to previously reported sPLA2 structures. The active site architecture, including the positions of the catalytic residues and the first and second shell water around the Ca2+ cofactor, are highly conserved and remarkably similar to the group IB and group IIA enzymes. Differences are seen in the structures following the (1-12)-N-terminal helix and at the C terminus. These regions are proposed to interact with the substrate membrane surface. The opening to the active site slot is considerably larger in hGX than in human group IIA sPLA2. Furthermore, the electrostatic surface potential of the hGX interfacial-binding surface does not resemble that of the human group IIA sPLA2; the former is highly neutral, whereas the latter is highly cationic. The cationic residues on this face of group IB and IIA enzymes have been implicated in membrane binding and in k(cat*) allostery. In contrast, hGX does not show activation by the anionic charge at the lipid interface when acting on phospholipid vesicles or short-chain phospholipid micelles. Together, the crystal structure and kinetic results of hGX supports the conclusion that it is as active on zwitterionic as on anionic interfaces, and thus it is predicted to target the zwitterionic membrane surfaces of mammalian cells. Crystal structure of human group X secreted phospholipase A2. Electrostatically neutral interfacial surface targets zwitterionic membranes.,Pan YH, Yu BZ, Singer AG, Ghomashchi F, Lambeau G, Gelb MH, Jain MK, Bahnson BJ J Biol Chem. 2002 Aug 9;277(32):29086-93. Epub 2002 May 25. PMID:12161451[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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