A substrate-induced switch in the reaction mechanism of a thermophilic esterase: kinetic evidences and structural basis.De Simone, G., Mandrich, L., Menchise, V., Giordano, V., Febbraio, F., Rossi, M., Pedone, C., Manco, G.
(2004) J.Biol.Chem. 279: 6815-6823
- PubMed: 14617621
- DOI: 10.1074/jbc.M307738200
- Also Cited By: 1U4N
- PubMed Abstract:
- A SNAPSHOT OF THE TRANSITION STATE ANALOGUE OF A NOVEL THERMOPHILIC ESTERASE BELONGING TO THE SUBFAMILY OF MAMMALIAN HORMONE-SENSITIVE LIPASE
DE SIMONE, G.,GALDIERO, S.,MANCO, G.,LANG, D.,ROSSI, M.,PEDONE, C.
(2000) J.Mol.Biol. 303: 761
The reaction mechanism of the esterase 2 (EST2) from Alicyclobacillus acidocaldarius was studied at the kinetic and structural level to shed light on the mechanism of activity and substrate specificity increase previously observed in its double mutan ...
The reaction mechanism of the esterase 2 (EST2) from Alicyclobacillus acidocaldarius was studied at the kinetic and structural level to shed light on the mechanism of activity and substrate specificity increase previously observed in its double mutant M211S/R215L. In particular, the values of kinetic constants (k1, k(-1), k2, and k3) along with activation energies (E1, E(-1), E2, and E3) were measured for wild type and mutant enzyme. The previously suggested substrate-induced switch in the reaction mechanism from kcat=k3 with a short acyl chain substrate (p-nitrophenyl hexanoate) to kcat=k2 with a long acyl chain substrate (p-nitrophenyl dodecanoate) was validated. The inhibition afforded by an irreversible inhibitor (1-hexadecanesulfonyl chloride), structurally related to p-nitrophenyl dodecanoate, was studied by kinetic analysis. Moreover the three-dimensional structure of the double mutant bound to this inhibitor was determined, providing essential information on the enzyme mechanism. In fact, structural analysis explained the observed substrate-induced switch because of an inversion in the binding mode of the long acyl chain derivatives with respect to the acyl- and alcohol-binding sites.
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