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oai:gumushane-rdlopen.rawdatalibrary.net:gumushane/152522026-10-22T11:37:51Zopenairedrivercom_gumushane_10000col_gumushane_10001com_gumushane_10007col_gumushane_10171

Kinetic characterization of GES-22 β-lactamase harboring the M169L clinical mutationSaral, AysegulLeonard, David ADuzgun, Azer OzadCicek, Aysegul CopurJune, Cynthia MSandalli, CemalThe class A β-lactamase GES-22 has been identified in Acinetobacter baumannii isolates in Turkey, and subsequently shown to differ from GES-11 by a single substitution (M169L). Because M169 is part of the omega loop, a structure that is known to have major effects on substrate selectivity in class A β-lactamases, we expressed, purified and kinetically characterized this novel variant. Our results show that compared with GES-116×His, GES-226×His displays more efficient hydrolysis of penicillins, and aztreonam, but a loss of efficiency against ceftazidime. In addition, the M169L substitution confers on GES-22 more efficient hydrolysis of the mechanistic inhibitors clavulanic acid and sulbactam. These effects are highly similar to other mutations at the homologous position in other class A β-lactamases, suggesting that this methionine has a key structural role in aligning active site residues and in substrate selectivity across the class.Nature Publishing Group2016Articlehttps://rdlopen.rawdatalibrary.net/r/gumushane/15252https://doi.org/10.1038/ja.2016.480021-8820enJournal of Antibioticsinfo:eu-repo/semantics/openAccessinfo:eu-repo/semantics/articlehttps://gumushane-rdlopen.rawdatalibrary.net/tr/items/gumushane/15252