Biochemical and molecular characterization of three new variants of AmpC beta-lactamases from Morganella morganii.

ABSTRACT: Morganella morganii produces an inducible, chromosomally encoded AmpC beta-lactamase. We describe in this study three new variants of AmpC within this species with apparent pIs of 6.6 (M19 from M. morganii strain PP19), 7.4 (M29 from M. morganii strain PP29), and 7.8 (M37 from M. morganii strain PP37). After gene sequencing, deduced amino acid sequences displayed one to six substitutions when compared to the available Morganella AmpC sequences. An AmpR-encoding gene was also found upstream of ampC, including the LysR regulators' helix-turn-helix DNA-binding domain and the putative T-N11-A-protected region in the ampR-ampC intercistronic sequence. All three AmpC variants were purified from in vitro-generated derepressed mutants and showed overall similar kinetic parameters. None of the obse

SUBMITTER: Power P 

PROVIDER: S-EPMC1426437 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature