1CK3

N276D MUTANT OF ESCHERICHIA COLI TEM-1 BETA-LACTAMASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.28 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.165 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

X-ray structure of the Asn276Asp variant of the Escherichia coli TEM-1 beta-lactamase: direct observation of electrostatic modulation in resistance to inactivation by clavulanic acid.

Swaren, P.Golemi, D.Cabantous, S.Bulychev, A.Maveyraud, L.Mobashery, S.Samama, J.P.

(1999) Biochemistry 38: 9570-9576

  • DOI: 10.1021/bi990758z

  • PubMed Abstract: 
  • The clinical use of beta-lactam antibiotics combined with beta-lactamase inactivators, such as clavulanate, has resulted in selection of beta-lactamases that are insensitive to inactivation by these molecules. Therefore, therapeutic combinations of a ...

    The clinical use of beta-lactam antibiotics combined with beta-lactamase inactivators, such as clavulanate, has resulted in selection of beta-lactamases that are insensitive to inactivation by these molecules. Therefore, therapeutic combinations of an enzyme inactivator and a penicillin are harmless for bacteria harboring such an enzyme. The TEM beta-lactamase variants are the most frequently encountered enzymes of this type, and presently, 20 variants are designated as inhibitor-resistant TEM ("IRT") enzymes. Three mutations appear to account for the phenotype of the majority of IRT enzymes, one of them being the Asn276Asp substitution. In this study, we have characterized the kinetic properties of the inhibition process of the wild-type TEM-1 beta-lactamase and of its Asn276Asp variant with the three clinically used inactivators, clavulanic acid (clavulanate), sulbactam, and tazobactam, and we report the X-ray structure for the mutant variant at 2.3 A resolution. The changes in kinetic parameters for the interactions of the inhibitors with the wild-type and the mutant enzymes were more pronounced for clavulanate, and relatively inconsequential for sulbactam and tazobactam. The structure of the Asn276Asp mutant enzyme revealed a significant movement of Asp276 and the formation of a salt bridge of its side chain with the guanidinium group of Arg244, the counterion of the inhibitor carboxylate. A water molecule critical for the inactivation chemistry by clavulanate, which is observed in the wild-type enzyme structure, is not present in the crystal structure of the mutant variant. Such structural changes favor the turnover process over the inactivation chemistry for clavulanate, with profound phenotypic consequences. The report herein represents the best studied example of inhibitor-resistant beta-lactamases.


    Organizational Affiliation

    Groupe de Cristallographie Biologique, Institut de Pharmacologie et de Biologie Structurale du CNRS, Toulouse, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
BETA-LACTAMASE
A
263Escherichia coliGene Names: bla, blaT-3, blaT-4, blaT-5, blaT-6
EC: 3.5.2.6
Find proteins for P62593 (Escherichia coli)
Go to UniProtKB:  P62593
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.28 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.165 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 41.820α = 90.00
b = 60.360β = 90.00
c = 88.650γ = 90.00
Software Package:
Software NamePurpose
X-PLORphasing
MOSFLMdata reduction
X-PLORrefinement
X-PLORmodel building
CCP4data scaling
ROTAVATA/AGROVATAdata reduction
ROTAVATAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-08-18
    Type: Initial release
  • Version 1.1: 2008-04-26
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-04
    Type: Refinement description