5ZB7

CTX-M-64 apoenzyme


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.63 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.195 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

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

Cheng, Q.Xu, C.Chai, J.Zhang, R.Wai Chi Chan, E.Chen, S.

(2020) ACS Infect Dis 6: 577-587

  • DOI: 10.1021/acsinfecdis.9b00345
  • Primary Citation of Related Structures:  
    5ZB7, 6J25, 6J2O, 6J2K, 6J2B, 6ITY

  • PubMed 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, and notable examples are the CTX-M-190 and CTX-M-199 variants, which carried a S 130 T amino acid substitution and exhibited resistance to inhibitors such as sulbactam and tazobactam ...

    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, and notable examples are the CTX-M-190 and CTX-M-199 variants, which carried a S 130 T 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 (S 130 T) 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 (S 130 T) led to the conformational changes in such active site, which comprised the key residues involved in substrate catalysis, namely, Thr 130 , Lys 73 , Lys 234 , Asn 104 , and Asn 132 . 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)-T 130 bond, inefficient, thereby resulting in inhibitor resistance in CTX-M-64 (S 130 T). Understanding the mechanisms of inhibitor resistance provided structural insight for the future development of new inhibitors against inhibitor-resistant β-lactamases.


    Organizational Affiliation

    Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Beta-lactamaseA, B287Escherichia coliMutation(s): 0 
Gene Names: blaCTX-M-64F1E19_16420pHNAH46_020
EC: 3.5.2.6
UniProt
Find proteins for C8CP57 (Escherichia coli)
Explore C8CP57 
Go to UniProtKB:  C8CP57
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.63 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.195 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.123α = 90
b = 106.898β = 99.8
c = 47.521γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-3000data reduction
HKL-3000data scaling
PHASERphasing

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

  • Deposited Date: 2018-02-10 
  • Released Date: 2019-02-13 
  • Deposition Author(s): Cheng, Q., Chen, S.

Revision History  (Full details and data files)

  • Version 1.0: 2019-02-13
    Type: Initial release
  • Version 1.1: 2020-05-13
    Changes: Database references, Structure summary