Role of ser-237 in the substrate specificity of the carbapenem-hydrolyzing class A beta-lactamase Sme-1. |
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| Authors: | W Sougakoff T Naas P Nordmann E Collatz V Jarlier |
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| Institution: | Laboratoire de Recherche Moléculaire sur les Antibiotiques (LRMA), Faculté de Médecine Pitié-Salpêtrière, Université Pierre et Marie Curie, 91 boulevard de l'H?pital, F-75634, Paris Cedex 13, Paris, France. sougakof@lmcp.jussieu.fr |
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| Abstract: | The role of the serine residue found at position 237 in the carbapenemase Sme-1 has been investigated by constructing a mutant in which Ser-237 was replaced by an alanine. The S237A mutant showed a catalytic behavior against penicillins and aztreonam very similar to that of Sme-1. By contrast, S237A was characterized by a reduced catalytic efficiency against cephems, such as cephalothin and cephaloridine. In addition, the weak activity of Sme-1 against the cephamycin cefoxitin was hardly detectable with the mutant enzyme. Finally, the Ser-237-->Ala mutation resulted in a marked decrease in catalytic activity against imipenem, showing that Ser-237 contributes to the carbapenemase activity of the class A beta-lactamase Sme-1. |
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