Structural Insight into the Mechanism of Inhibitor-Resistance in CTX-M-199, a CTX-M-64 Variant Carrying the S130T Substitution

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Author(s)

  • Qipeng Cheng
  • Chen Xu
  • Jiachang Chai
  • Rong Zhang
  • Edward Wai Chi Chan

Detail(s)

Original languageEnglish
Pages (from-to)577-587
Journal / PublicationACS Infectious Diseases
Volume6
Issue number4
Online published11 Nov 2019
Publication statusPublished - 10 Apr 2020

Abstract

The smart design of β-lactamase inhibitors allowed us to combat extended-spectrum β-lactamase (ESBL)-producing organisms for many years without developing resistance to these inhibitors. However, novel resistant variants have emerged recently, notable examples are the CTX-M-190 and CTX-M-199 variants, which carried a S130T amino acid substitution and exhibited resistance to inhibitors such as sulbactam and tazobactam. Using mass spectrometric and crystallographic approaches, this study depicted the mechanisms of inhibitor resistance. Our data showed that CTX-M-64 (S130T) did not cause any conformational change or exert any effect on its ability to hydrolyze β-lactam substrates. However, binding of sulbactam, but not clavulanic acid, to the active site of CTX-M-64 (S130T) led to the conformational changes in such active site, which comprised the key residues involved in substrate catalysis, namely Thr130, Lys73, Lys234, Asn104 and Asn132. This conformational change weakened the binding of the sulbactam trans-enamine intermediate (TSL) to the active site and rendered the formation of the inhibitor-enzyme complex, which features a covalent acrylic acid (AKR)-T130 bond, inefficient, thereby resulting in inhibitor resistance in CTX-M-64 (S130T). Understanding the mechanisms of inhibitor resistance provided structural insight for future development of new inhibitors against inhibitor-resistant β-lactamases.

Research Area(s)

  • CTX-M-199, CTX-M-64, CTX-M-64 (S130T), Inhibitor resistance, Mechanism, Structure insights

Citation Format(s)

Structural Insight into the Mechanism of Inhibitor-Resistance in CTX-M-199, a CTX-M-64 Variant Carrying the S130T Substitution. / Cheng, Qipeng; Xu, Chen; Chai, Jiachang; Zhang, Rong; Chan, Edward Wai Chi; Chen, Sheng.

In: ACS Infectious Diseases, Vol. 6, No. 4, 10.04.2020, p. 577-587.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal