Plasticity of Aminoglycoside Binding to Antibiotic Kinase APH(2″)-Ia.

Autor:	Caldwell SJ; Department of Biochemistry, McGill University, Montreal, Canada.; Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Canada., Berghuis AM; Department of Biochemistry, McGill University, Montreal, Canada albert.berghuis@mcgill.ca.; Groupe de Recherche Axé sur la Structure des Protéines, McGill University, Montreal, Canada.; Department of Microbiology and Immunology, McGill University, Montreal, Canada.
Jazyk:	angličtina
Zdroj:	Antimicrobial agents and chemotherapy [Antimicrob Agents Chemother] 2018 Jun 26; Vol. 62 (7). Date of Electronic Publication: 2018 Jun 26 (Print Publication: 2018).
DOI:	10.1128/AAC.00202-18
Abstrakt:	The APH(2″)-Ia aminoglycoside resistance enzyme forms the C-terminal domain of the bifunctional AAC(6')-Ie/APH(2″)-Ia enzyme and confers high-level resistance to natural 4,6-disubstituted aminoglycosides. In addition, reports have suggested that the enzyme can phosphorylate 4,5-disubstituted compounds and aminoglycosides with substitutions at the N1 position. Previously determined structures of the enzyme with bound aminoglycosides have not indicated how these noncanonical substrates may bind and be modified by the enzyme. We carried out crystallographic studies to directly observe the interactions of these compounds with the aminoglycoside binding site and to probe the means by which these noncanonical substrates interact with the enzyme. We find that APH(2″)-Ia maintains a preferred mode of binding aminoglycosides by using the conserved neamine rings when possible, with flexibility that allows it to accommodate additional rings. However, if this binding mode is made impossible because of additional substitutions to the standard 4,5- or 4,6-disubstituted aminoglycoside architecture, as in lividomycin A or the N1-substituted aminoglycosides, it is still possible for these aminoglycosides to bind to the antibiotic binding site by using alternate binding modes, which explains the low rates of noncanonical phosphorylation activities seen in enzyme assays. Furthermore, structural studies of a clinically observed arbekacin-resistant mutant of APH(2″)-Ia revealed an altered aminoglycoside binding site that can stabilize an alternative binding mode for N1-substituted aminoglycosides. This mutation may alter and expand the aminoglycoside resistance spectrum of the wild-type enzyme in response to newly developed aminoglycosides. (Copyright © 2018 American Society for Microbiology.)
Databáze:	MEDLINE
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