1eth
From Proteopedia
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'''TRIACYLGLYCEROL LIPASE/COLIPASE COMPLEX''' | '''TRIACYLGLYCEROL LIPASE/COLIPASE COMPLEX''' | ||
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[[Category: Kerfelec, B.]] | [[Category: Kerfelec, B.]] | ||
[[Category: Pignol, D.]] | [[Category: Pignol, D.]] | ||
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Revision as of 12:30, 2 May 2008
TRIACYLGLYCEROL LIPASE/COLIPASE COMPLEX
Overview
The crystal structure of the ternary porcine lipase-colipase-tetra ethylene glycol monooctyl ether (TGME) complex has been determined at 2.8 A resolution. The crystals belong to the cubic space group F23 with a = 289.1 A and display a strong pseudo-symmetry corresponding to a P23 lattice. Unexpectedly, the crystalline two-domain lipase is found in its open configuration. This indicates that in the presence of colipase, pure micelles of the nonionic detergent TGME are able to activate the enzyme; a process that includes the movement of an N-terminal domain loop (the flap). The effects of TGME and colipase have been confirmed by chemical modification of the active site serine residue using diisopropyl p-nitrophenylphosphate (E600). In addition, the presence of a TGME molecule tightly bound to the active site pocket shows that TGME acts as a substrate analog, thus possibly explaining the inhibitory effect of this nonionic detergent on emulsified substrate hydrolysis at submicellar concentrations. A comparison of the lipase-colipase interactions between our porcine complex and the human-porcine complex (van Tilbeurgh, H., Egloff, M.-P., Martinez, C., Rugani, N., Verger, R., and Cambillau, C.(1993) Nature 362, 814-820) indicates that except for one salt bridge interaction, they are conserved. Analysis of the superimposed complexes shows a 5.4 degrees rotation on the relative position of the N-terminal domains excepting the flap that moves in a concerted fashion with the C-terminal domain. This flexibility may be important for the binding of the complex to the water-lipid interface.
About this Structure
1ETH is a Protein complex structure of sequences from Sus scrofa. Full crystallographic information is available from OCA.
Reference
Lipase activation by nonionic detergents. The crystal structure of the porcine lipase-colipase-tetraethylene glycol monooctyl ether complex., Hermoso J, Pignol D, Kerfelec B, Crenon I, Chapus C, Fontecilla-Camps JC, J Biol Chem. 1996 Jul 26;271(30):18007-16. PMID:8663362 Page seeded by OCA on Fri May 2 15:30:01 2008
