1qz3
From Proteopedia
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CRYSTAL STRUCTURE OF MUTANT M211S/R215L OF CARBOXYLESTERASE EST2 COMPLEXED WITH HEXADECANESULFONATE
Overview
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.
About this Structure
1QZ3 is a Single protein structure of sequence from Alicyclobacillus acidocaldarius with as ligand. Active as Carboxylesterase, with EC number 3.1.1.1 Full crystallographic information is available from OCA.
Reference
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, J Biol Chem. 2004 Feb 20;279(8):6815-23. Epub 2003 Nov 15. PMID:14617621
Page seeded by OCA on Thu Feb 21 14:45:22 2008
