5lip
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PSEUDOMONAS LIPASE COMPLEXED WITH RC-(RP, SP)-1,2-DIOCTYLCARBAMOYLGLYCERO-3-O-OCTYLPHOSPHONATE
OverviewOverview
To investigate the enantioselectivity of Pseudomonas cepacia lipase, inhibition studies were performed with Sc- and, Rc-(Rp,Sp)-1,2-dialkylcarbamoylglycero-3-O-p-nitrophenyl alkylphosphonates, of different alkyl chain lengths. P. cepacia lipase was most rapidly, inactivated by Rc-(Rp,Sp)-1,2-dioctylcarbamoylglycero-3-O-p-nitrophenyl, octylphosphonate (Rc-trioctyl) with an inactivation half-time of 75 min, while that for the, Sc-(Rp,Sp)-1,2-dioctylcarbamoylglycero-3-O-p-nitrophenyl octyl-phosphonate, (Sc-trioctyl) compound was 530 min. X-ray structures were obtained of P., cepacia lipase after reaction with Rc-trioctyl to 0.29-nm resolution at pH, 4 and covalently modified with, Rc-(Rp,Sp)-1,2-dibutylcarbamoylglycero-3-O-p-nitrophenyl butyl-phosphonate, (Rc-tributyl) to 0.175-nm resolution at pH 8.5. The three-dimensional, structures reveal that both triacylglycerol analogues had reacted with the, active-site Ser87, forming a covalent complex. The bound phosphorus atom, shows the same chirality (Sp) in both complexes despite the use of a, racemic (Rp,Sp) mixture at the phosphorus atom of the triacylglycerol, analogues. In the structure of Rc-tributyl-complexed P. cepacia lipase, the diacylglycerol moiety has been lost due to an aging reaction, and only, the butyl phosphonate remains visible in the electron density. In the, Rc-trioctyl complex the complete inhibitor is clearly defined; it adopts a, bent tuning fork conformation. Unambiguously, four binding pockets for the, triacylglycerol could be detected: an oxyanion hole and three pockets, which accommodate the sn-1, sn-2, and sn-3 fatty acid chains. Van der, Waals' interactions are the main forces that keep the radyl groups of the, triacylglycerol analogue in position and, in addition, a hydrogen bond to, the carbonyl oxygen of the sn-2 chain contributes to fixing the position, of the inhibitor.
About this StructureAbout this Structure
5LIP is a Single protein structure of sequence from Burkholderia cepacia with and as ligands. Active as Triacylglycerol lipase, with EC number 3.1.1.3 Known structural/functional Sites: and . Full crystallographic information is available from OCA.
ReferenceReference
Structural basis of the chiral selectivity of Pseudomonas cepacia lipase., Lang DA, Mannesse ML, de Haas GH, Verheij HM, Dijkstra BW, Eur J Biochem. 1998 Jun 1;254(2):333-40. PMID:9660188
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