Inhibition of Dog and Human Gastric Lipases by Enantiomeric Phosphonate Inhibitors: A Structure−Activity Study
| Autor: | Mireille Rivière, Nabil Miled, Cécile Bussetta, Christian Cambillau, Liliane Berti-Dupuis, Gérard Buono, Alain Roussel, Robert Verger, Stéphane Canaan |
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| Rok vydání: | 2003 |
| Předmět: |
Models
Molecular Stereochemistry Organophosphonates Stereoisomerism Crystallography X-Ray Binding Competitive Biochemistry Structure-Activity Relationship chemistry.chemical_compound Dogs Tetrahedral carbonyl addition compound Animals Humans Computer Simulation Enzyme Inhibitors Triglycerides Binding Sites biology Chemistry Hydrogen bond Stomach Absolute configuration Active site Lipase Phosphonate biology.protein Alkoxy group Enantiomer Crystallization Protein Binding |
| Zdroj: | Biochemistry. 42:11587-11593 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi034964p |
| Popis: | The crystal structures of gastric lipases in the apo form [Roussel, A., et al. (1999) J. Biol. Chem. 274, 16995-17002] or in complex with the (R(P))-undecyl butyl phosphonate [C(11)Y(4)(+)] [Roussel, A., et al. (2002) J. Biol. Chem. 277, 2266-2274] have improved our understanding of the structure-activity relationships of acid lipases. In this report, we have performed a kinetic study with dog and human gastric lipases (DGL and HGL, respectively) using several phosphonate inhibitors by varying the absolute configuration of the phosphorus atom and the chain length of the alkyl/alkoxy substituents. Using the two previously determined structures and that of a new crystal structure obtained with the other (S(P))-phosphonate enantiomer [C(11)Y(4)(-)], we constructed models of phosphonate inhibitors fitting into the active site crevices of DGL and HGL. All inhibitors with a chain length of fewer than 12 carbon atoms were found to be completely buried in the catalytic crevice, whereas longer alkyl/alkoxy chains were found to point out of the cavity. The main stereospecific determinant explaining the stronger inhibition of the S(P) enantiomers is the presence of a hydrogen bond involving the catalytic histidine as found in the DGL-C(11)Y(4)(-) complex. On the basis of these results, we have built a model of the first tetrahedral intermediate corresponding to the tristearoyl-lipase complex. The triglyceride molecule completely fills the active site crevice of DGL, in contrast with what is observed with other lipases such as pancreatic lipases which have a shallower and narrower active site. For substrate hydrolysis, the supply of water molecules to the active site might be achieved through a lateral channel identified in the protein core. |
| Databáze: | OpenAIRE |
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