title: Studies on amino acid replacement and inhibitory activity of a beta-lactamase inhibitory peptide.
abstract: An SHV beta-lactamase gene was amplified from a beta-lactam resistant Klebsiella pneumoniae K-71 genomic DNA. After expression and purification, we demonstrated that peptide P1 could inhibit the hydrolysis activity of both TEM-1 and SHV beta-lactamase in vitro. Three mutations were introduced into P1 in which the first residue S was replaced by F, the 18th residue V was mutated to Y, and the 15th residue Y was substituted with A, C, G, and R to obtain the mutants of P1-A, P1-C, P1-G, and P1-R, respectively. The mutant peptides were purified and their inhibitory constants against TEM-1 and SHV beta-lactamase were determined. All these beta-lactamase inhibitory peptides could inhibit the activity of both beta-lactamases, while the mutant peptides showed stronger inhibitory activities against TEM-1 beta-lactamase than against SHV beta-lactamase. Inhibition data suggested that P1-A improved the beta-lactamase inhibitory activity by over 3-fold compare to P1. When P1-A was incubated with K. pneumoniae K-71 in Luria-Bertani medium containing ampicillin, it showed a much stronger growth of inhibition ratio over P1. This study gives us a good candidate for development of novel beta-lactamase inhibitors.
authors.affiliation: State Key Laboratory of New Drug and Pharmaceutical Process, Shanghai Institute of Pharmaceutical Industry, Shanghai, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Xie
authors.forename: Mingfei
authors.initials: M
authors.lastname: Xu
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Chunbao
authors.initials: C
authors.lastname: Zhu
authors.forename: Baoquan
authors.initials: B
authors.lastname: Zhu
authors.forename: Youjia
authors.initials: Y
authors.lastname: Hu
mesh_terms: D019943:Amino Acid Substitution; D001483:Base Sequence; D017931:DNA Primers; D004587:Electrophoresis, Agar Gel; D006868:Hydrolysis; D010455:Peptides / Q000494:pharmacology*; D065093:beta-Lactamase Inhibitors
chemical_list: D017931:DNA Primers; D010455:Peptides; D065093:beta-Lactamase Inhibitors