1VQ2

CRYSTAL STRUCTURE OF T4-BACTERIOPHAGE DEOXYCYTIDYLATE DEAMINASE, MUTANT R115E


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.218 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Three-Dimensional Structure of the R115E Mutant of T4-Bacteriophage 2'-Deoxycytidylate Deaminase

Almog, R.Maley, F.Maley, G.F.Maccoll, R.Van Roey, P.

(2004) Biochemistry 43: 13715

  • DOI: 10.1021/bi048928h
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • 2'-Deoxycytidylate deaminase (dCD) converts deoxycytidine 5'-monophosphate (dCMP) to deoxyuridine 5'-monophosphate and is a major supplier of the substrate for thymidylate synthase, an important enzyme in DNA synthesis and a major target for cancer c ...

    2'-Deoxycytidylate deaminase (dCD) converts deoxycytidine 5'-monophosphate (dCMP) to deoxyuridine 5'-monophosphate and is a major supplier of the substrate for thymidylate synthase, an important enzyme in DNA synthesis and a major target for cancer chemotherapy. Wild-type dCD is allosterically regulated by the end products of its metabolic pathway, deoxycytidine 5'-triphosphate and deoxythymidine 5'-triphosphate, which act as an activator and an inhibitor, respectively. The first crystal structure of a dCD, in the form of the R115E mutant of the T4-bacteriophage enzyme complexed with the active site inhibitor pyrimidin-2-one deoxyribotide, has been determined at 2.2 A resolution. This mutant of dCD is active, even in the absence of the allosteric regulators. The molecular topology of dCD is related to that of cytidine deaminase (CDA) but with modifications for formation of the binding site for the phosphate group of dCMP. The enzyme has a zinc ion-based mechanism that is similar to that of CDA. A second zinc ion that is present in bacteriophage dCD, but absent in mammalian dCD and CDA, is important for the structural integrity of the enzyme and for the binding of the phosphate group of the substrate or inhibitor. Although the R115E mutant of dCD is a dimer in solution, it crystallizes as a hexamer, mimicking the natural state of the wild-type enzyme. Residues 112 and 115, which are known to be important for the binding of the allosteric regulators, are found in a pocket that is at the intersubunit interfaces in the hexamer but distant from the substrate-binding site. The substrate-binding site is composed of residues from a single protein molecule and is sequestered in a deep groove. This groove is located at the outer surface of the hexamer but ends at the subunit interface that also includes residue 115. It is proposed that the absence of subunit interactions at this interface in the dimeric R115E mutant renders the substrate-binding site accessible. In contrast, for the wild-type enzyme, binding of dCTP induces an allosteric effect that affects the subunit interactions and results in an increase in the accessibility of the binding site.


    Organizational Affiliation

    Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
DEOXYCYTIDYLATE DEAMINASE
A
193Enterobacteria phage T4Mutation(s): 1 
Gene Names: CD
EC: 3.5.4.12
Find proteins for P16006 (Enterobacteria phage T4)
Go to UniProtKB:  P16006
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
DDN
Query on DDN

Download SDF File 
Download CCD File 
A
3,4-DIHYDRO-2'-DEOXYURIDINE-5'-MONOPHOSPHATE
((2R,3S,5R)-3-HYDROXY-5-(4-HYDROXY-2-OXO-3,4-DIHYDROPYRIMIDIN-1(2H)-YL)-TETRAHYDROFURAN-2-YL)METHYL DIHYDROGEN PHOSPHATE
C9 H15 N2 O8 P
ILSIYJVILUIVPM-LXGUWJNJSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.245 
  • R-Value Work: 0.218 
  • Space Group: P 63 2 2
Unit Cell:
Length (Å)Angle (°)
a = 114.528α = 90.00
b = 114.528β = 90.00
c = 76.950γ = 120.00
Software Package:
Software NamePurpose
SOLVEphasing
CNSrefinement
HKL-2000data collection
SCALEPACKdata scaling
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-12-21
    Type: Initial release
  • Version 1.1: 2008-04-26
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance