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: https://doi.org/10.1074/jbc.M307738200
- Primary Citation of Related Structures:
- 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 mutant M211S/R215L ...
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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