3G77

Bacterial cytosine deaminase V152A/F316C/D317G mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.171 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Bacterial cytosine deaminase mutants created by molecular engineering show improved 5-fluorocytosine-mediated cell killing in vitro and in vivo.

Fuchita, M.Ardiani, A.Zhao, L.Serve, K.Stoddard, B.L.Black, M.E.

(2009) Cancer Res. 69: 4791-4799

  • DOI: 10.1158/0008-5472.CAN-09-0615

  • PubMed Abstract: 
  • Cytosine deaminase is used in combination with 5-fluorocytosine as an enzyme-prodrug combination for targeted genetic cancer treatment. This approach is limited by inefficient gene delivery and poor prodrug conversion activities. Previously, we repor ...

    Cytosine deaminase is used in combination with 5-fluorocytosine as an enzyme-prodrug combination for targeted genetic cancer treatment. This approach is limited by inefficient gene delivery and poor prodrug conversion activities. Previously, we reported individual point mutations within the substrate binding pocket of bacterial cytosine deaminase (bCD) that result in marginal improvements in the ability to sensitize cells to 5-fluorocytosine (5FC). Here, we describe an expanded random mutagenesis and selection experiment that yielded enzyme variants, which provide significant improvement in prodrug sensitization. Three of these mutants were evaluated using enzyme kinetic analyses and then assayed in three cancer cell lines for 5FC sensitization, bystander effects, and formation of 5-fluorouracil metabolites. All variants displayed 18- to 19-fold shifts in substrate preference toward 5FC, a significant reduction in IC(50) values and improved bystander effect compared with wild-type bCD. In a xenograft tumor model, the best enzyme mutant was shown to prevent tumor growth at much lower doses of 5FC than is observed when tumor cells express wild-type bCD. Crystallographic analyses of this construct show the basis for improved activity toward 5FC, and also how two different mutagenesis strategies yield closely related but mutually exclusive mutations that each result in a significant alteration of enzyme specificity.


    Organizational Affiliation

    School of Molecular Biosciences and Department of Pharmaceutical Sciences, Washington State University, Pullman, Washington 99164-6534, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cytosine deaminase
A
423Escherichia coli (strain K12)Mutation(s): 3 
Gene Names: codA
EC: 3.5.4.1
Find proteins for P25524 (Escherichia coli (strain K12))
Go to UniProtKB:  P25524
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FE
Query on FE

Download SDF File 
Download CCD File 
A
FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.171 
  • Space Group: H 3 2
Unit Cell:
Length (Å)Angle (°)
a = 108.938α = 90.00
b = 108.938β = 90.00
c = 240.762γ = 120.00
Software Package:
Software NamePurpose
CrystalCleardata collection
REFMACrefinement
PDB_EXTRACTdata extraction
PHASESphasing
d*TREKdata scaling
CrystalCleardata scaling
CrystalCleardata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2009-02-09 
  • Released Date: 2009-09-22 
  • Deposition Author(s): Stoddard, B., Zhao, L.

Revision History 

  • Version 1.0: 2009-09-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance