Characterization of a novel SHV beta-lactamase variant that resembles the SHV-5 enzyme.
FEMS Microbiol Lett, 1996/6/01;139(2-3):229-34.
Prinarakis EE[1], Tzelepi E, Gazouli M, Mentis AF, Tzouvelekis LS
Affiliations
PMID: 8674992
Impact factor: 2.82
Abstract
An SHV type beta-lactamase frequently found in enterobacteria isolated in Greek hospitals was analyzed. The enzyme (SHV-5a) conferred resistance to ceftazidime and aztreonam. The DNA sequence of the structural gene was determined. The deduced amino acid sequence showed that positions 70-73 were occupied by the active site tetrad Ser-Thr-Phe-Lys. As in SHV-5, Ser-238 and Lys-240 were present. However, one deletion (Gly-54) and three substitutions (Arg-140 for Ala, Asn-192 for Lys and Val-193 for Leu) differentiate SHV-5a beta-lactamase from SHV-5. Asn-192 and Val-193 have been reported to date only in the R974 plasmid-mediate SHV-1 beta-lactamase. Hydrolysis studies with SHV-5a and SHV-5 showed that the enzymes behaved similarly. Additional evidence that they are functionally indistinguishable was provided by the similar MICs of beta-lactams when the enzymes were expressed under isogenic conditions. The sequence differences, however, indicate that they are derived from different ancestors.
MeSH terms
Amino Acid Sequence; Base Sequence; DNA, Bacterial; Enterobacteriaceae; Escherichia coli; Genetic Variation; Isoelectric Focusing; Klebsiella pneumoniae; Molecular Sequence Data; Plasmids; Serratia marcescens; beta-Lactamases
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