1FR1

REFINED CRYSTAL STRUCTURE OF BETA-LACTAMASE FROM CITROBACTER FREUNDII INDICATES A MECHANISM FOR BETA-LACTAM HYDROLYSIS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Observed: 0.182 

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This is version 1.3 of the entry. See complete history


Literature

Refined crystal structure of beta-lactamase from Citrobacter freundii indicates a mechanism for beta-lactam hydrolysis.

Oefner, C.D'Arcy, A.Daly, J.J.Gubernator, K.Charnas, R.L.Heinze, I.Hubschwerlen, C.Winkler, F.K.

(1990) Nature 343: 284-288

  • DOI: 10.1038/343284a0
  • Primary Citation of Related Structures:  
    1FR1, 1FR6

  • PubMed Abstract: 
  • Beta-Lactamases (EC 3.5.2.6, 'penicillinases') are a family of enzymes that protect bacteria against the lethal effects of cell-wall synthesis of penicillins, cephalosporins and related antibiotic agents, by hydrolysing the beta-lactam antibiotics to biologically inactive compounds ...

    Beta-Lactamases (EC 3.5.2.6, 'penicillinases') are a family of enzymes that protect bacteria against the lethal effects of cell-wall synthesis of penicillins, cephalosporins and related antibiotic agents, by hydrolysing the beta-lactam antibiotics to biologically inactive compounds. Their production can, therefore, greatly contribute to the clinical problem of antibiotic resistance. Three classes of beta-lactamases--A, B and C--have been identified on the basis of their amino-acid sequence; class B beta-lactamases are metalloenzymes, and are clearly distinct from members of class A and C beta-lactamases, which both contain an active-site serine residue involved in the formation of an acyl enzyme with beta-lactam substrates during catalysis. It has been predicted that class C beta-lactamases share common structural features with D,D-carboxypeptidases and class A beta-lactamases, and further, suggested that class A and class C beta-lactamases have the same evolutionary origin as other beta-lactam target enzymes. We report here the refined three-dimensional structure of the class C beta-lactamase from Citrobacter freundii at 2.0-A resolution and confirm the predicted structural similarity. The refined structure of the acyl-enzyme formed with the monobactam inhibitor aztreonam at 2.5-A resolution defines the enzyme's active site and, along with molecular modelling, indicates a mechanism for beta-lactam hydrolysis. This leads to the hypothesis that Tyr 150 functions as a general base during catalysis.


    Organizational Affiliation

    Central Research Unit, F. Hoffmann-La Roche Co. Ltd, Basel, Switzerland.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
BETA-LACTAMASEA, B361Citrobacter freundiiMutation(s): 0 
EC: 3.5.2.6
UniProt
Find proteins for Q46041 (Citrobacter freundii)
Explore Q46041 
Go to UniProtKB:  Q46041
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Observed: 0.182 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 98.07α = 90
b = 84.63β = 90
c = 89.77γ = 90
Software Package:
Software NamePurpose
CCP4model building
TNTrefinement
X-GENdata reduction
X-GENdata scaling
CCP4phasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-01-17
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description