NMR experiments to study inhibition of enzymes that confer bacterial resistance

Yara Lins Rocha – @YaraLRocha

NMR experiments to study inhibition of enzyme OXA-143 that confer bacterial resistance! #GlobalNMRTC2023 #BiologicalNMR #NMRchat pic.twitter.com/a0ysWVh9S5

— Yara Lins (@YaraLRocha) July 19, 2023

Enzymes belonging to the Carbapenem-Hydrolyzing Class D β-lactamases (CHDL’s) confer bacterial resistance to β-lactam antibiotics and are often associated with outbreaks involving the pathogenic bacteria Acinetobacter baumannii. We report the inhibition of CHDL OXA-143 by the reaction product with meropenem, a carbapenem antibiotic, in addition to describing its effect on protein structure and dynamics. Kinetic 1H-NMR experiments were performed to assess how hMER interferes with the catalytic efficiency of the enzyme against ampicillin and meropenem itself, indicating a clear inhibition. Chemical shift perturbation (CSP) was performed using 15N-HSQC and 15N-TROSY titration experiments. The results indicate that hMER acts as a competitive inhibitor blocking the active site and decreasing the dynamics of essential motifs around the binding site.