A natural TEM variant β-lactamase was isolated from an epidemic strain of Serratia marcescens. Nucleotide gene sequencing revealed multiple point mutations located in the 42-to-44 tripeptide and positions 145 to 146, 178, and 238. In addition, a glutamic acid 212 deletion was also found. The purified enzyme was studied from a kinetic point of view, revealing the highest catalytic efficiency (k(cat)/K(m)) values for ceftazidime and aztreonam compared with the TEM-1 prototype enzyme. The in vitro resistance correlated with kinetic parameters, and the enzyme also mediated resistance to some penicillins and an ampicillin-clavulanic acid combination. The mutational and kinetic changes are discussed in relation to the three- dimensional crystallographic structure of the wild-type TEM-1 enzyme.
Perilli, M., Felici, A., Franceschini, N., De Santis, A., Pagani Luzzaro, F., Oratore, A., et al. (1997). Characterization of a new TEM-derived beta-lactamase produced in a Serratia marcescens strain. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 41(11), 2374-2382 [10.1128/AAC.41.11.2374].
Characterization of a new TEM-derived beta-lactamase produced in a Serratia marcescens strain
Rossolini G. M.;
1997-01-01
Abstract
A natural TEM variant β-lactamase was isolated from an epidemic strain of Serratia marcescens. Nucleotide gene sequencing revealed multiple point mutations located in the 42-to-44 tripeptide and positions 145 to 146, 178, and 238. In addition, a glutamic acid 212 deletion was also found. The purified enzyme was studied from a kinetic point of view, revealing the highest catalytic efficiency (k(cat)/K(m)) values for ceftazidime and aztreonam compared with the TEM-1 prototype enzyme. The in vitro resistance correlated with kinetic parameters, and the enzyme also mediated resistance to some penicillins and an ampicillin-clavulanic acid combination. The mutational and kinetic changes are discussed in relation to the three- dimensional crystallographic structure of the wild-type TEM-1 enzyme.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/11365/29248
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