1Q15

Carbapenam Synthetase

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.249 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history. 


Literature

Crystal Structure of Carbapenam Synthetase (CarA)

Miller, M.T., Gerratana, B., Stapon, A., Townsend, C.A., Rosenzweig, A.C.

(2003) J Biol Chem 278: 40996-41002

  • DOI: 10.1074/jbc.M307901200
  • Primary Citation of Related Structures:  
    1Q15, 1Q19

  • PubMed Abstract: 

    • Carbapenam synthetase (CarA) is an ATP/Mg2+-dependent enzyme that catalyzes formation of the beta-lactam ring in (5R)-carbapenem-3-carboxylic acid biosynthesis. CarA is homologous to beta-lactam synthetase (beta-LS), which is involved in clavulanic acid biosynthesis ...

    Carbapenam synthetase (CarA) is an ATP/Mg2+-dependent enzyme that catalyzes formation of the beta-lactam ring in (5R)-carbapenem-3-carboxylic acid biosynthesis. CarA is homologous to beta-lactam synthetase (beta-LS), which is involved in clavulanic acid biosynthesis. The catalytic cycles of CarA and beta-LS mediate substrate adenylation followed by beta-lactamization via a tetrahedral intermediate or transition state. Another member of this family of ATP/Mg2+-dependent enzymes, asparagine synthetase (AS-B), catalyzes intermolecular, rather than intramolecular, amide bond formation in asparagine biosynthesis. The crystal structures of apo-CarA and CarA complexed with the substrate (2S,5S)-5-carboxymethylproline (CMPr), ATP analog alpha,beta-methyleneadenosine 5'-triphosphate (AMP-CPP), and a single Mg2+ ion have been determined. CarA forms a tetramer. Each monomer resembles beta-LS and AS-B in overall fold, but key differences are observed. The N-terminal domain lacks the glutaminase active site found in AS-B, and an extended loop region not observed in beta-LS or AS-B is present. Comparison of the C-terminal synthetase active site to that in beta-LS reveals that the ATP binding site is highly conserved. By contrast, variations in the substrate binding pocket reflect the different substrates of the two enzymes. The Mg2+ coordination is also different. Several key residues in the active site are conserved between CarA and beta-LS, supporting proposed roles in beta-lactam formation. These data provide further insight into the structures of this class of enzymes and suggest that CarA might be a versatile target for protein engineering experiments aimed at developing improved production methods and new carbapenem antibiotics.

    Organizational Affiliation: 

    Department of Biochemistry, Northwestern University, Evanston, Illinois 60208, USA.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CarA A, B, C, D503Pectobacterium carotovorumMutation(s): 0 
EC: 6.3.3.6
Find proteins for Q9XB61 (Pectobacterium carotovorum subsp. carotovorum)
Explore Q9XB61 
Go to UniProtKB:  Q9XB61
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.249 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 61.101α = 90
b = 180.388β = 97.46
c = 96.633γ = 90
Software Package:
Software NamePurpose
CNSrefinement
MOSFLMdata reduction
CCP4data scaling
SOLVEphasing

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-11-04
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance