Two laboratory mutants of NDM-1 were generated by replacing the isoleucine at position 35 with threonine and serine residues: the NDM-1I35T and NDM-1I35S enzymes. These mutants were well characterized, and their kinetic parameters were compared with those of the NDM-1 wild type. The kcat, Km, and kcat/Km values calculated for the two mutants were slightly different from those of the wild-type enzyme. Interestingly, the kcat/Km of NDM-1I35S for loracarbef was about 14-fold higher than that of NDM-1. Far-UV circular dichroism (CD) spectra of NDM-1 and NDM-1I35T and NDM-1I35S enzymes suggest local structural rearrangements in the secondary structure with a marked reduction of α-helix content in the mutants.
Kinetic study of laboratory mutants of NDM-1 metallo-β-lactamase and the importance of an isoleucine at position 35
MARCOCCIA, FRANCESCA;BOTTONI, CARLO;SABATINI, ALESSIA;COLAPIETRO, MARTINA;CELENZA, GIUSEPPE;AMICOSANTE, Gianfranco;PERILLI, MARIAGRAZIA
2016-01-01
Abstract
Two laboratory mutants of NDM-1 were generated by replacing the isoleucine at position 35 with threonine and serine residues: the NDM-1I35T and NDM-1I35S enzymes. These mutants were well characterized, and their kinetic parameters were compared with those of the NDM-1 wild type. The kcat, Km, and kcat/Km values calculated for the two mutants were slightly different from those of the wild-type enzyme. Interestingly, the kcat/Km of NDM-1I35S for loracarbef was about 14-fold higher than that of NDM-1. Far-UV circular dichroism (CD) spectra of NDM-1 and NDM-1I35T and NDM-1I35S enzymes suggest local structural rearrangements in the secondary structure with a marked reduction of α-helix content in the mutants.Pubblicazioni consigliate
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