Arginine Modulates Carbapenem Deactivation by OXA-24/40 in Acinetobacter baumannii. Issue 19 (17th September 2021)

• Record Type: Journal Article
• Authors: VanPelt, Jamie; Stoffel, Shannon; Staude, Michael W.; Dempster, Kayla; Rose, Heath A.; Graney, Sarah; Graney, Erin; Braynard, Sara; Kovrigina, Elizaveta; Leonard, David A.; Peng, Jeffrey W.
• Is Part Of: Journal of molecular biology. Volume 433:Issue 19(2021)
• Publication Date: 2021-09-17
• Subjects: carbapenem -- allostery -- CHDL -- real-time -- protein dynamics; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2021.167150
• Languages: English
• ISSNs: 0022-2836

Abstract

Graphical abstract: Highlights: Real-Time NMR studies of OXA-24/40 during turnover of a carbapenem, doripenem. Doripenem deactivated by multiple mechanisms supported by distinct active sites. Mechanism preference modulated by R261, a conserved active site residue. Mutations altering the bound carbapenem pose(s) may enhance latent mechanisms. Abstract: The resistance of Gram-negative bacteria to β-lactam antibiotics stems mainly from β-lactamase proteins that hydrolytically deactivate the β-lactams. Of particular concern are the β-lactamases that can deactivate a class of β-lactams known as carbapenems. Carbapenems are among the few anti-infectives that can treat multi-drug resistant bacterial infections. Revealing the mechanisms of their deactivation by β-lactamases is a necessary step for preserving their therapeutic value. Here, we present NMR investigations of OXA-24/40, a carbapenem-hydrolyzing Class D β-lactamase (CHDL) expressed in the gram-negative pathogen, Acinetobacter baumannii . Using rapid data acquisition methods, we were able to study the "real-time" deactivation of the carbapenem known as doripenem by OXA-24/40. Our results indicate that OXA-24/40 has two deactivation mechanisms: canonical hydrolytic cleavage, and a distinct mechanism that produces a β-lactone product that has weak affinity for the OXA-24/40 active site. The mechanisms issue from distinct active site environments poised either for hydrolysis or β-lactone formation. Mutagenesis reveals that R261, a conserved active site arginine, stabilizes the active site environment enabling β-lactone formation. Our results have implications not only for OXA-24/40, but the larger family of CHDLs now challenging clinical settings on a global scale.