title: Design and exploration of novel boronic acid inhibitors reveals important interactions with a clavulanic acid-resistant sulfhydryl-variable (SHV) β-lactamase.
abstract: Inhibitor resistant (IR) class A β-lactamases pose a significant threat to many current antibiotic combinations. The K234R substitution in the SHV β-lactamase, from  Klebsiella pneumoniae , results in resistance to ampicillin/clavulanate. After site-saturation mutagenesis of Lys-234 in SHV, microbiological and biochemical characterization of the resulting β-lactamases revealed that only -Arg conferred resistance to ampicillin/clavulanate. X-ray crystallography revealed two conformations of Arg-234 and Ser-130 in SHV K234R. The movement of Ser-130 is the principal cause of the observed clavulanate resistance. A panel of boronic acid inhibitors was designed and tested against SHV-1 and SHV K234R. A chiral ampicillin analogue was discovered to have a 2.4 ± 0.2 nM K(i) for SHV K234R; the chiral ampicillin analogue formed a more complex hydrogen-bonding network in SHV K234R vs SHV-1. Consideration of the spatial position of Ser-130 and Lys-234 and this hydrogen-bonding network will be important in the design of novel antibiotics targeting IR β-lactamases.
authors.affiliation: Department of Microbiology and Molecular Biology, Case Western Reserve University, Cleveland, Ohio 44106, USA.
authors.forename: Marisa L
authors.initials: ML
authors.lastname: Winkler
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Rodkey
authors.forename: Magdalena A
authors.initials: MA
authors.lastname: Taracila
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Drawz
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Bethel
authors.forename: Krisztina M
authors.initials: KM
authors.lastname: Papp-Wallace
authors.forename: Kerri M
authors.initials: KM
authors.lastname: Smith
authors.forename: Yan
authors.initials: Y
authors.lastname: Xu
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Dwulit-Smith
authors.forename: Chiara
authors.initials: C
authors.lastname: Romagnoli
authors.forename: Emilia
authors.initials: E
authors.lastname: Caselli
authors.forename: Fabio
authors.initials: F
authors.lastname: Prati
authors.forename: Focco
authors.initials: F
authors.lastname: van den Akker
authors.forename: Robert A
authors.initials: RA
authors.lastname: Bonomo
mesh_terms: D001897:Boronic Acids / Q000737:chemistry / Q000494:pharmacology; D002942:Circular Dichroism; D019818:Clavulanic Acid / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D015195:Drug Design; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D016296:Mutagenesis; D017433:Protein Structure, Secondary; D021241:Spectrometry, Mass, Electrospray Ionization; D013438:Sulfhydryl Compounds / Q000494:pharmacology*; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000737:chemistry
chemical_list: D001897:Boronic Acids; D013438:Sulfhydryl Compounds; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D001618:beta-Lactamases