Structural Analysis of The OXA-48 Carbapenemase Bound to A "Poor" Carbapenem Substrate, Doripenem

• Published in: Antibiotics (Basel) Vol. 8; no. 3; p. 145
• Main Authors: Papp-Wallace, Krisztina M, Kumar, Vijay, Zeiser, Elise T, Becka, Scott A, van den Akker, Focco
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 11.09.2019; MDPI
• Subjects: Antibiotics; Beta lactamases; carbapenem-resistant Enterobacteriaceae; Carbapenemase; Carbapenems; Cloning; Crystal structure; Data collection; Deacylation; Doripenem; EDTA; Enterobacteriaceae; Enzymes; Health aspects; Health risks; Hydrogen; Hydrogen bonding; Hydrolysis; Imipenem; Laboratories; Meropenem; OXA-48; Oxalic acid; Pathogens; Phenotypes; Physiological aspects; Proteins; Public health; Public health movements; Residues; Structural analysis; structural biology; Structure; Substrates; Van der Waals forces; United States; carbapenem-resistant Enterobacteriaceae; structural biology; carbapenemase; OXA-48
• ISSN: 2079-6382; 2079-6382
• DOI: 10.3390/antibiotics8030145

Carbapenem-resistant Enterobacteriaceae are a significant threat to public health, and a major resistance determinant that promotes this phenotype is the production of the OXA-48 carbapenemase. The activity of OXA-48 towards carbapenems is a puzzling phenotype as its hydrolytic activity against doripenem is non-detectable. To probe the mechanistic basis for this observation, we determined the 1.5 Å resolution crystal structure of the deacylation deficient K73A variant of OXA-48 in complex with doripenem. Doripenem is observed in the Δ R and Δ S tautomeric states covalently attached to the catalytic S70 residue. Likely due to positioning of residue Y211, the carboxylate moiety of doripenem is making fewer hydrogen bonding/salt-bridge interactions with R250 compared to previously determined carbapenem OXA structures. Moreover, the hydroxyethyl side chain of doripenem is making van der Waals interactions with a key V120 residue, which likely affects the deacylation rate of doripenem. We hypothesize that positions V120 and Y211 play important roles in the carbapenemase profile of OXA-48. Herein, we provide insights for the further development of the carbapenem class of antibiotics that could render them less effective to hydrolysis by or even inhibit OXA carbapenemases.