Comparative biochemical and computational study of the role of naturally occurring mutations at Ambler positions 104 and 170 in GES β-lactamases.

ABSTRACT: In GES-type β-lactamases, positions 104 and 170 are occupied by Glu or Lys and by Gly, Asn, or Ser, respectively. Previous studies have indicated an important role of these amino acids in the interaction with β-lactams, although their precise role, especially that of residue 104, remains uncertain. In this study, we constructed GES-1 (Glu104, Gly170), GES-2 (Glu104, Asn170), GES-5 (Glu104, Ser170), GES-6 (Lys104, Ser170), GES-7 (Lys104, Gly170), and GES-13 (Lys104, Asn170) by site-specific mutagenesis and compared their hydrolytic properties. Isogenic comparisons of β-lactam resistance levels conferred by these GES variants were also performed. Data indicated the following patterns: (i) Lys104-containing enzymes exhibited enhanced hydrolysis of oxyimino-cephalosporins and reduced efficienc

SUBMITTER: Kotsakis SD 

PROVIDER: S-EPMC2976113 | biostudies-literature | 2010 Nov

REPOSITORIES: biostudies-literature