8EHH

Crystal structure of the class A extended-spectrum beta-lactamase CTX-M-96 in complex with relebactam at 1.03 Angstrom resolution

Summary for 8EHH

• Entry DOI: 10.2210/pdb8ehh/pdb
• Related: 3ZNY
• Descriptor: Beta-lactamase, (2S,5R)-1-formyl-N-(piperidin-4-yl)-5-[(sulfooxy)amino]piperidine-2-carboxamide (3 entities in total)
• Functional Keywords: beta-lactamase inhibitor, dbo, esbl, ceftazidimase, antimicrobial protein
• Biological source: Klebsiella pneumoniae
• Total number of polymer chains: 1
• Total formula weight: 28476.22

Authors

Power, P.,Ghiglione, B.,Bonomo, R.A.,Rodriguez, M.M.,Gutkind, G.,Klinke, S. (deposition date: 2022-09-14, release date: 2023-09-20, Last modification date: 2024-10-09)

Primary citation

Ghiglione, B.,Rodriguez, M.M.,Penzotti, P.,Bethel, C.R.,Gutkind, G.,Bonomo, R.A.,Klinke, S.,Power, P.
Crystal structure of the class A extended-spectrum beta-lactamase CTX-M-96 in complex with relebactam at 1.03 Angstrom resolution.
Antimicrob.Agents Chemother., 68:e0172123-e0172123, 2024

PubMed Abstract: The use of β-lactam/β-lactamase inhibitors constitutes an important strategy to counteract β-lactamases in multidrug-resistant (MDR) Gram-negative bacteria. Recent reports have described ceftazidime-/avibactam-resistant isolates producing CTX-M variants with different amino acid substitutions (e.g., P167S, L169Q, and S130G). Relebactam (REL) combined with imipenem has proved very effective against Enterobacterales producing ESBLs, serine-carbapenemases, and AmpCs. Herein, we evaluated the inhibitory efficacy of REL against CTX-M-96, a CTX-M-15-type variant. The CTX-M-96 structure was obtained in complex with REL at 1.03 Å resolution (PDB 8EHH). REL was covalently bound to the S70-Oγ atom upon cleavage of the C7-N6 bond. Compared with apo CTX-M-96, binding of REL forces a slight displacement of the deacylating water inwards the active site (0.81 Å), making the E166 and N170 side chains shift to create a proper hydrogen bonding network. Binding of REL also disturbs the hydrophobic patch formed by Y105, P107, and Y129, likely due to the piperidine ring of REL that creates clashes with these residues. Also, a remarkable change in the positioning of the N104 sidechain is also affected by the piperidine ring. Therefore, differences in the kinetic behavior of REL against class A β-lactamases seem to rely, at least in part, on differences in the residues being involved in the association and stabilization of the inhibitor before hydrolysis. Our data provide the biochemical and structural basis for REL effectiveness against CTX-M-producing Gram-negative pathogens and essential details for further DBO design. Imipenem/REL remains an important choice for dealing with isolates co-producing CTX-M with other β-lactamases.

PubMed: 38990013
DOI: 10.1128/aac.01721-23

Experimental method

X-RAY DIFFRACTION (1.03 Å)