The mechanism of NDM-1-catalyzed carbapenem hydrolysis is distinct from that of penicillin or cephalosporin hydrolysis.
Feng, H., Liu, X., Wang, S., Fleming, J., Wang, D.C., Liu, W.(2017) Nat Commun 8: 2242-2242
- PubMed: 29269938 
- DOI: https://doi.org/10.1038/s41467-017-02339-w
- Primary Citation of Related Structures:  
5YPI, 5YPK, 5YPL, 5YPM, 5YPN - PubMed Abstract: 
New Delhi metallo-β-lactamases (NDMs), the recent additions to metallo-β-lactamases (MBLs), pose a serious public health threat due to its highly efficient hydrolysis of β-lactam antibiotics and rapid worldwide dissemination. The MBL-hydrolyzing mechanism for carbapenems is less studied than that of penicillins and cephalosporins. Here, we report crystal structures of NDM-1 in complex with hydrolyzed imipenem and meropenem, at resolutions of 1.80-2.32 Å, together with NMR spectra monitoring meropenem hydrolysis. Three enzyme-intermediate/product derivatives, EI 1 , EI 2 , and EP, are trapped in these crystals. Our structural data reveal double-bond tautomerization from Δ 2 to Δ 1 , absence of a bridging water molecule and an exclusive β-diastereomeric product, all suggesting that the hydrolytic intermediates are protonated by a bulky water molecule incoming from the β-face. These results strongly suggest a distinct mechanism of NDM-1-catalyzed carbapenem hydrolysis from that of penicillin or cephalosporin hydrolysis, which may provide a novel rationale for design of mechanism-based inhibitors.
Organizational Affiliation: 
National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.