An engineered Staphylococcus aureus PCI {beta}-lactamase that hydrolyses third-generation cephalosporins |
| |
Authors: | Zawadzke Laura E; Smith Tom J; Herzberg Osnat |
| |
Affiliation: | Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, 9600 Gudelsky Dr., Rockville, MD 20850, USA |
| |
Abstract: | The ß-lactamase from Staphylococcus aureus PCI hasbeen cloned into an Escherichia coli vector for site-directedmutagenesis and high-level protein expression. A mutant enzymehas been produced in which Ala238 is replaced by a serine, andIle239 is deleted (A238S:I239del). The engineered enzyme hydrolysesthird-generation cephalosporins substantially more rapidly thanthe parental enzyme does, while hydrolysis of benzylpenicillinis slower with the mutant than with the wild-type and nativeenzymes. The mutant P-lactamase has been crystallized and thestructure determined and refined at 2.8 A resolution. The dispositionof the ß-strand which forms the side of the activesite is altered in comparison with the native S.aureus ß-lactamasestructure, widening the active site cleft and providing spaceto accommodate the bulky side-chains of the third-generationcephalosporins. |
| |
Keywords: | ß -lactam kinetics/ ß -lactamase/ site-directed mutagenesis/ third-generation cephalosporins/ X-ray structure |
本文献已被 Oxford 等数据库收录! |
|