1le6
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CARBOXYLIC ESTER HYDROLASE, P 1 21 1 SPACE GROUP
OverviewOverview
The 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.
About this StructureAbout this Structure
1LE6 is a Single protein structure of sequence from Homo sapiens with CA and MPD as ligands. Active as Phospholipase A(2), with EC number 3.1.1.4 Full crystallographic information is available from OCA.
ReferenceReference
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
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