Crystal structure of the Mycobacterium tuberculosis beta-lactamase

Experimental Data Snapshot

  • Resolution: 1.72 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.180 

Starting Model: experimental
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Crystal Structure and Activity Studies of the Mycobacterium tuberculosis {beta}-Lactamase Reveal Its Critical Role in Resistance to {beta}-Lactam Antibiotics.

Wang, F.Cassidy, C.Sacchettini, J.C.

(2006) Antimicrob Agents Chemother 50: 2762-2771

  • DOI: https://doi.org/10.1128/AAC.00320-06
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    beta-Lactam antibiotics are extremely effective in disrupting the synthesis of the bacterial cell wall in both gram-positive and gram-negative bacteria. However, they are ineffective against Mycobacterium tuberculosis, due to the production of a beta-lactamase enzyme encoded on the chromosome of M. tuberculosis that degrades these antibiotics. Indeed, recent studies have demonstrated that deletion of the blaC gene, the only gene encoding a beta-lactamase in M. tuberculosis, or inhibition of the encoded enzyme resulted in significantly increased sensitivity to beta-lactam antibiotics. In this paper we present a biochemical and structural characterization of M. tuberculosis BlaC. Recombinant BlaC shows a broad range of specificity with almost equal penicillinase and cepholothinase activity. While clavulanate is a mechanism-based inhibitor to class A beta-lactamase with high potency (typically K(i) < 0.1 microM), it is a relatively poor inhibitor of the M. tuberculosis BlaC (K(i) = 2.4 microM). The crystal structure of the enzyme, determined at a resolution of 1.7 A, shows that the overall fold of the M. tuberculosis enzyme is similar to other class A beta-lactamases. There are, however, several distinct features of the active site, such as the amino acid substitutions N132G, R164A, R244A, and R276E, that explain the broad specificity of the enzyme, relatively low penicillinase activity, and resistance to clavulanate.

  • Organizational Affiliation

    Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Beta-lactamase267Mycobacterium tuberculosisMutation(s): 0 
Gene Names: blaAblaC
Find proteins for P9WKD3 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WKD3 
Go to UniProtKB:  P9WKD3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WKD3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.72 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.180 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.744α = 90
b = 71.283β = 90
c = 85.169γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
ADSCdata collection

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-04-18
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2023-08-30
    Changes: Data collection, Database references, Refinement description