1YMX

X-ray crystallographic structure of CTX-M-9 beta-lactamase covalently linked to cefoxitin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.158 

wwPDB Validation 3D Report Full Report



Literature

Structure, Function, and Inhibition along the Reaction Coordinate of CTX-M beta-Lactamases.

Chen, Y.Shoichet, B.Bonnet, R.

(2005) J Am Chem Soc 127: 5423-5434

  • DOI: 10.1021/ja042850a
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • CTX-M enzymes are an emerging group of extended spectrum beta-lactamases (ESBLs) that hydrolyze not only the penicillins but also the first-, second-, and third-generation cephalosporins. Although they have become the most frequently observed ESBLs in certain areas, there are few effective inhibitors and relatively little is known about their detailed mechanism ...

    CTX-M enzymes are an emerging group of extended spectrum beta-lactamases (ESBLs) that hydrolyze not only the penicillins but also the first-, second-, and third-generation cephalosporins. Although they have become the most frequently observed ESBLs in certain areas, there are few effective inhibitors and relatively little is known about their detailed mechanism. Here we describe the X-ray crystal structures of CTX-M enzymes in complex with different transition-state analogues and beta-lactam inhibitors, representing the enzyme as it progresses from its acylation transition state to its acyl enzyme complex to the deacylation transition state. As the enzyme moves along this reaction coordinate, two key catalytic residues, Lys73 and Glu166, change conformations, tracking the state of the reaction. Unexpectedly, the acyl enzyme complex with the beta-lactam inhibitor cefoxitin still has the catalytic water bound; this water had been predicted to be displaced by the unusual 7alpha-methoxy of the inhibitor. Instead, the 7alpha-group appears to inhibit by preventing the formation of the deacylation transition state through steric hindrance. From an inhibitor design standpoint, we note that the best of the reversible inhibitors, a ceftazidime-like boronic acid compound, binds to CTX-M-16 with a K(i) value of 4 nM. When used together in cell culture, this inhibitor reversed cefotaxime resistance in CTX-M-producing bacteria. The structure of its complex with CTX-M enzyme and the structural view of the reaction coordinate described here provide templates for inhibitor design and intervention to combat this family of antibiotic resistance enzymes.


    Organizational Affiliation

    Department of Pharmaceutical Chemistry, University of California, San Francisco, Genentech Hall, 600 16th Street, San Francisco, California 94143-2240, USA.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
beta-lactamase CTX-M-9A, B263Escherichia coliMutation(s): 0 
Gene Names: CTX-MblaCTX-M-9abla CTX-M-9blaCTX-M-9blaCTX-M-9bRCS51_P0174
EC: 3.5.2.6
Find proteins for Q9L5C8 (Escherichia coli)
Explore Q9L5C8 
Go to UniProtKB:  Q9L5C8
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
1QL
Query on 1QL

Download CCD File 
A, B
(2R)-5-[(carbamoyloxy)methyl]-2-{(1S)-1-methoxy-2-oxo-1-[(thiophen-2-ylacetyl)amino]ethyl}-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid
C16 H19 N3 O7 S2
IYZWSAWEHPQLHS-ZBFHGGJFSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
CFXIC50 :  14000   nM  PDBBind
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.197 
  • R-Value Work: 0.158 
  • R-Value Observed: 0.158 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.209α = 90
b = 106.781β = 101.62
c = 47.779γ = 90
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-04-26
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2018-09-12
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Non-polymer description, Structure summary