4PM9

Crystal structure of CTX-M-14 S70G:S237A:R276A beta-lactamase in complex with cefotaxime at 1.45 Angstroms resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.454 Å
  • R-Value Free: 0.180 
  • R-Value Work: 0.161 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Molecular Basis for the Catalytic Specificity of the CTX-M Extended-Spectrum beta-Lactamases.

Adamski, C.J.Cardenas, A.M.Brown, N.G.Horton, L.B.Sankaran, B.Prasad, B.V.Gilbert, H.F.Palzkill, T.

(2015) Biochemistry 54: 447-457

  • DOI: 10.1021/bi501195g
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Extended-spectrum β-lactamases (ESBLs) pose a threat to public health because of their ability to confer resistance to extended-spectrum cephalosporins such as cefotaxime. The CTX-M β-lactamases are the most widespread ESBL enzymes among antibiotic r ...

    Extended-spectrum β-lactamases (ESBLs) pose a threat to public health because of their ability to confer resistance to extended-spectrum cephalosporins such as cefotaxime. The CTX-M β-lactamases are the most widespread ESBL enzymes among antibiotic resistant bacteria. Many of the active site residues are conserved between the CTX-M family and non-ESBL β-lactamases such as TEM-1, but the residues Ser237 and Arg276 are specific to the CTX-M family, suggesting that they may help to define the increased specificity for cefotaxime hydrolysis. To test this hypothesis, site-directed mutagenesis of these positions was performed in the CTX-M-14 β-lactamase. Substitutions of Ser237 and Arg276 with their TEM-1 counterparts, Ala237 and Asn276, had a modest effect on cefotaxime hydrolysis, as did removal of the Arg276 side chain in an R276A mutant. The S237A:R276N and S237A:R276A double mutants, however, exhibited 29- and 14-fold losses in catalytic efficiency for cefotaxime hydrolysis, respectively, while the catalytic efficiency for benzylpenicillin hydrolysis was unchanged. Therefore, together, the Ser237 and Arg276 residues are important contributors to the cefotaximase substrate profile of the enzyme. High-resolution crystal structures of the CTX-M-14 S70G, S70G:S237A, and S70G:S237A:R276A variants alone and in complex with cefotaxime show that residues Ser237 and Arg276 in the wild-type enzyme promote the expansion of the active site to accommodate cefotaxime and favor a conformation of cefotaxime that allows optimal contacts between the enzyme and substrate. The conservation of these residues, linked to their effects on structure and catalysis, imply that their coevolution is an important specificity determinant in the CTX-M family.


    Organizational Affiliation

    Verna and Marrs McLean Department of Biochemistry and Molecular Biology, ‡Department of Molecular Virology and Microbiology, ∥Department of Pharmacology, Baylor College of Medicine , One Baylor Plaza, Houston, Texas 77030, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Beta-lactamase CTX-M-14
A
262Klebsiella pneumoniae subsp. pneumoniae (strain HS11286)Mutation(s): 3 
EC: 3.5.2.6
Find proteins for A0A0H3H219 (Klebsiella pneumoniae subsp. pneumoniae (strain HS11286))
Go to UniProtKB:  A0A0H3H219
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CE3
Query on CE3

Download SDF File 
Download CCD File 
A
(6R,7R)-3-(acetyloxymethyl)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-methoxyimino-ethanoyl]amino]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid
CEFOTAXIME
C16 H17 N5 O7 S2
GPRBEKHLDVQUJE-QSWIMTSFSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.454 Å
  • R-Value Free: 0.180 
  • R-Value Work: 0.161 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 41.530α = 90.00
b = 61.737β = 90.00
c = 86.675γ = 90.00
Software Package:
Software NamePurpose
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious DiseasesUnited StatesR01 AI32956

Revision History 

  • Version 1.0: 2014-12-31
    Type: Initial release
  • Version 1.1: 2015-03-04
    Type: Database references
  • Version 1.2: 2017-09-13
    Type: Author supporting evidence, Database references, Derived calculations, Other, Source and taxonomy