Mutant R188M of the Cytidine Monophosphate Kinase From E. Coli

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.231 
  • R-Value Observed: 0.231 

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Structural and functional consequences of single amino acid substitutions in the pyrimidine base binding pocket of Escherichia coli CMP kinase.

Ofiteru, A.Bucurenci, N.Alexov, E.Bertrand, T.Briozzo, P.Munier-Lehmann, H.Gilles, A.M.

(2007) FEBS J 274: 3363-3373

  • DOI: https://doi.org/10.1111/j.1742-4658.2007.05870.x
  • Primary Citation of Related Structures:  
    2FEM, 2FEO

  • PubMed Abstract: 

    Bacterial CMP kinases are specific for CMP and dCMP, whereas the related eukaryotic NMP kinase phosphorylates CMP and UMP with similar efficiency. To explain these differences in structural terms, we investigated the contribution of four key amino acids interacting with the pyrimidine ring of CMP (Ser36, Asp132, Arg110 and Arg188) to the stability, catalysis and substrate specificity of Escherichia coli CMP kinase. In contrast to eukaryotic UMP/CMP kinases, which interact with the nucleobase via one or two water molecules, bacterial CMP kinase has a narrower NMP-binding pocket and a hydrogen-bonding network involving the pyrimidine moiety specific for the cytosine nucleobase. The side chains of Arg110 and Ser36 cannot establish hydrogen bonds with UMP, and their substitution by hydrophobic amino acids simultaneously affects the K(m) of CMP/dCMP and the k(cat) value. Substitution of Ser for Asp132 results in a moderate decrease in stability without significant changes in K(m) value for CMP and dCMP. Replacement of Arg188 with Met does not affect enzyme stability but dramatically decreases the k(cat)/K(m) ratio compared with wild-type enzyme. This effect might be explained by opening of the enzyme/nucleotide complex, so that the sugar no longer interacts with Asp185. The reaction rate for different modified CMP kinases with ATP as a variable substrate indicated that none of changes induced by these amino acid substitutions was 'propagated' to the ATP subsite. This 'modular' behavior of E. coli CMP kinase is unique in comparison with other NMP kinases.

  • Organizational Affiliation

    Laboratory of Enzymology and Applied Microbiology, Cantacuzino Institute, Bucharest, Romania.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cytidylate kinase227Escherichia coliMutation(s): 1 
Gene Names: cmkmssA
Find proteins for P0A6I0 (Escherichia coli (strain K12))
Explore P0A6I0 
Go to UniProtKB:  P0A6I0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A6I0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.231 
  • R-Value Observed: 0.231 
  • Space Group: P 63
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.167α = 90
b = 82.167β = 90
c = 60.726γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-01-10
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-10-20
    Changes: Database references
  • Version 1.4: 2024-02-14
    Changes: Data collection