Crystal structures of the molecular class A beta-lactamase TEM-171 and its complexes with tazobactam.
Grigorenko, V.G., Petrova, T.E., Carolan, C., Rubtsova, M.Y., Uporov, I.V., Pereira, J., Chojnowski, G., Samygina, V.R., Lamzin, V.S., Egorov, A.M.(2022) Acta Crystallogr D Struct Biol 78: 825-834
- PubMed: 35775982 
- DOI: https://doi.org/10.1107/S2059798322004879
- Primary Citation of Related Structures:  
7QLP, 7QNK, 7QOR - PubMed Abstract: 
The resistance of bacteria to β-lactam antibiotics is primarily caused by the production of β-lactamases. Here, novel crystal structures of the native β-lactamase TEM-171 and two complexes with the widely used inhibitor tazobactam are presented, alongside complementary data from UV spectroscopy and fluorescence quenching. The six chemically identical β-lactamase molecules in the crystallographic asymmetric unit displayed different degrees of disorder. The tazobactam intermediate was covalently bound to the catalytic Ser70 in the trans-enamine configuration. While the conformation of tazobactam in the first complex resembled that in published β-lactamase-tazobactam structures, in the second complex, which was obtained after longer soaking of the native crystals in the inhibitor solution, a new and previously unreported tazobactam conformation was observed. It is proposed that the two complexes correspond to different stages along the deacylation path of the acyl-enzyme intermediate. The results provide a novel structural basis for the rational design of new β-lactamase inhibitors.
Organizational Affiliation: 
Chemistry Department, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation.