Identification of the Catalytic Residues of Carboxylesterase fromArthrobacter globiformisby Diisopropyl Fluorophosphate-Labeling and Site-Directed Mutagenesis | Zendy

Masako Nishizawa | Zendy; Yoshiyasu Yabusaki | Zendy; Masaharu Kanaoka | Zendy

Open Access

Identification of the Catalytic Residues of Carboxylesterase fromArthrobacter globiformisby Diisopropyl Fluorophosphate-Labeling and Site-Directed Mutagenesis

Author(s) -

Masako Nishizawa,

Yoshiyasu Yabusaki,

Masaharu Kanaoka

Publication year - 2011

Publication title -

bioscience biotechnology and biochemistry

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 0.509

H-Index - 116

eISSN - 1347-6947

pISSN - 0916-8451

DOI - 10.1271/bbb.100576

Subject(s) - diisopropyl fluorophosphate , chemistry , carboxylesterase , site directed mutagenesis , active site , esterase , catalytic triad , biochemistry , mutagenesis , electrospray ionization , serine , residue (chemistry) , stereochemistry , iodoacetamide , enzyme , mutant , chromatography , cysteine , mass spectrometry , gene

The role of amino acid residues in the enzymatic activity of carboxylesterase from Arthrobacter globiformis was analyzed by diisopropyl fluorophosphate (DFP) labeling and site-directed mutagenesis. The electrospray ionization mass spectrometric (ESI-MS) analysis of the esterase, covalently labeled by DFP, showed stoichiometric incorporation of the inhibitor into the enzyme. The further comparison of endopeptidase-digested fragments between native and DFP-labeled esterase by fast atom bombardment mass spectrometric (FAB-MS) analysis as well as site-directed mutagenesis indicated that Ser59 in the consensus sequence Ser-X-X-Lys, which is conserved exclusively in penicillin-binding proteins and some esterases, served as a catalytic nucleophile. In addition, the results obtained from analysis of the mutants at position 62 suggested the importance of the basic amino acid side chain at this position, and suggested the significance of this residue acting directly as a general base rather than its involvement in the maintenance of the optimum hydrogen-bonding network at the active site.

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