Crystal structures of the molecular class A β-lactamase TEM-171 and its complexes with tazobactam

Acta Crystallogr D Struct Biol. 2022 Jul 1;78(Pt 7):825-834. doi: 10.1107/S2059798322004879. Epub 2022 Jun 7.

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.

Keywords: UV spectroscopy; antibiotic resistance; crystal structure; enzyme inhibition; tazobactam intermediate; β-lactamase TEM-171.

MeSH terms

  • Crystallography, X-Ray
  • Enzyme Inhibitors / chemistry
  • Penicillanic Acid* / chemistry
  • Penicillanic Acid* / metabolism
  • Penicillanic Acid* / pharmacology
  • Tazobactam
  • beta-Lactamases* / chemistry

Substances

  • Enzyme Inhibitors
  • Penicillanic Acid
  • beta-Lactamases
  • Tazobactam