8JB7
Crystal structure of CMY-185
Summary for 8JB7
| Entry DOI | 10.2210/pdb8jb7/pdb |
| Descriptor | Beta-lactamase, SULFATE ION (3 entities in total) |
| Functional Keywords | beta-lactamase, cmy-2-like, hydrolase |
| Biological source | Escherichia coli |
| Total number of polymer chains | 2 |
| Total formula weight | 80155.41 |
| Authors | |
| Primary citation | Kawai, A.,Shropshire, W.C.,Suzuki, M.,Borjan, J.,Aitken, S.L.,Bachman, W.C.,McElheny, C.L.,Bhatti, M.M.,Shields, R.K.,Shelburne, S.A.,Doi, Y. Structural insights into the molecular mechanism of high-level ceftazidime-avibactam resistance conferred by CMY-185. Mbio, 15:e0287423-e0287423, 2024 Cited by PubMed Abstract: β-Lactamases can accumulate stepwise mutations that increase their resistance profiles to the latest β-lactam agents. CMY-185 is a CMY-2-like β-lactamase and was identified in an clinical strain isolated from a patient who underwent treatment with ceftazidime-avibactam. CMY-185, possessing four amino acid substitutions of A114E, Q120K, V211S, and N346Y relative to CMY-2, confers high-level ceftazidime-avibactam resistance, and accumulation of the substitutions incrementally enhances the level of resistance to this agent. However, the functional role of each substitution and their interplay in enabling ceftazidime-avibactam resistance remains unknown. Through biochemical and structural analysis, we present the molecular basis for the enhanced ceftazidime hydrolysis and impaired avibactam inhibition conferred by CMY-185. The substituted Y346 residue is a major driver of the functional evolution as it rejects primary avibactam binding due to the steric hindrance and augments oxyimino-cephalosporin hydrolysis through a drastic structural change, rotating the side chain of Y346 and then disrupting the H-10 helix structure. The other substituted residues E114 and K120 incrementally contribute to rejection of avibactam inhibition, while S211 stimulates the turnover rate of the oxyimino-cephalosporin hydrolysis. These findings indicate that the N346Y substitution is capable of simultaneously expanding the spectrum of activity against some of the latest β-lactam agents with altered bulky side chains and rejecting the binding of β-lactamase inhibitors. However, substitution of additional residues may be required for CMY enzymes to achieve enhanced affinity or turnover rate of the β-lactam agents leading to clinically relevant levels of resistance.IMPORTANCECeftazidime-avibactam has a broad spectrum of activity against multidrug-resistant Gram-negative bacteria including carbapenem-resistant including strains with or without production of serine carbapenemases. After its launch, emergence of ceftazidime-avibactam-resistant strains that produce mutated β-lactamases capable of efficiently hydrolyzing ceftazidime or impairing avibactam inhibition are increasingly reported. Furthermore, cross-resistance towards cefiderocol, the latest cephalosporin in clinical use, has been observed in some instances. Here, we clearly demonstrate the functional role of the substituted residues in CMY-185, a four amino-acid variant of CMY-2 identified in a patient treated with ceftazidime-avibactam, for high-level resistance to this agent and low-level resistance to cefiderocol. These findings provide structural insights into how β-lactamases may incrementally alter their structures to escape multiple advanced β-lactam agents. PubMed: 38179965DOI: 10.1128/mbio.02874-23 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.35 Å) |
Structure validation
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