Identification, crystallization and preliminary X‐ray diffraction analysis of esterase A from
Abstract:The structures and functions of family VIII lipolytic enzymes, which have moderate sequence identity to class C β‐lactamases and penicillin‐binding proteins, are largely unknown. Here, the X‐ray crystallographic study of a family VIII esterase from Caulobacter crescentus CB15 (CcEstA) is described. Sequence analysis revealed that CcEstA has a conserved serine residue within the S‐X‐X‐K motif which acts as a catalytic nucleophile. Recombinant protein containing an N‐terminal His tag was expressed in Escherichia coli and purified to homogeneity. Functional studies showed that CcEstA acts on α‐ and β‐naphthyl acetate as substrates. In addition, it can catalyze the hydrolysis of ketoprofen ethyl ester, a highly useful product in industrial applications. CcEstA was crystallized using a solution consisting of 1.0 M potassium/sodium tartrate, 0.1 M imidazole pH 8.0, 0.2 M NaCl, and X‐ray diffraction data were collected to a resolution of 1.62 Å with an R merge of 9.4%. The crystals of CcEstA belonged to space group C2221, with unit‐cell parameters a = 172.23, b = 176.68, c = 47.93 Å. Structure determination is in progress.
Document Type: Research Article
Publication date: May 1, 2012