1QKJ

T4 PHAGE B-GLUCOSYLTRANSFERASE, SUBSTRATE BINDING AND PROPOSED CATALYTIC MECHANISM


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.190 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

T4 Phage Beta-Glucosyltransferase: Substrate Binding and Proposed Catalytic Mechanism

Imberty, A.Aschke-Sonnenborn, U.Ruger, W.Freemont, P.S.Morera, S.

(1999) J.Mol.Biol. 292: 717

  • DOI: 10.1006/jmbi.1999.3094
  • Primary Citation of Related Structures:  1C3J

  • PubMed Abstract: 
  • beta-Glucosyltransferase (BGT) is a DNA-modifying enzyme encoded by bacteriophage T4 which catalyses the transfer of glucose (Glc) from uridine diphosphoglucose (UDP-Glc) to 5-hydroxymethylcytosine (5-HMC) in double-stranded DNA. The glucosylation of ...

    beta-Glucosyltransferase (BGT) is a DNA-modifying enzyme encoded by bacteriophage T4 which catalyses the transfer of glucose (Glc) from uridine diphosphoglucose (UDP-Glc) to 5-hydroxymethylcytosine (5-HMC) in double-stranded DNA. The glucosylation of T4 phage DNA is part of a phage DNA protection system aimed at host nucleases. We previously reported the first three-dimensional structure of BGT determined from crystals grown in ammonium sulphate containing UDP-Glc. In this previous structure, we did not observe electron density for the Glc moiety of UDP-Glc nor for two large surface loop regions (residues 68-76 and 109-122). Here we report two further BGT co-crystal structures, in the presence of UDP product (form I) and donor substrate UDP-Glc (form II), respectively. Form I crystals are grown in ammonium sulphate and the structure has been determined to 1.88 A resolution (R -factor 19.1 %). Form II crystals are grown in polyethyleneglycol 4000 and the structure has been solved to 2.3 A resolution (R -factor 19.8 %). The form I structure is isomorphous to our previous BGT UDP-Glc structure. The form II structure, however, has allowed us to model the two missing surface loop regions and thus provides the first complete structural description of BGT. In this low-salt crystal form, we see no electron density for the Glc moiety from UDP-Glc similar to previous observations. Biochemical data however, shows that BGT can cleave UDP-Glc in the absence of DNA acceptor, which probably accounts for the absence of Glc in our UDP-Glc substrate structures. The complete BGT structure now provides a basis for detailed modelling of a BGT HMC-DNA ternary complex. By using the structural similarity between the catalytic core of glycogen phosphorylase (GP) and BGT, we have modelled the position of the Glc moiety in UDP-Glc. From these two models, we propose a catalytic mechanism for BGT and identify residues involved in both DNA binding and in stabilizing a "flipped-out" 5-HMC nucleotide.


    Related Citations: 
    • Crystallization and Preliminary X-Ray Studies of T4 Phage Beta-Glucosyltransferase
      Freemont, P.S.,Rueger, W.
      (1988) J.Mol.Biol. 203: 525
    • Crystal Structure of the DNA Modifying Enzyme Beta-Glucosyltransferase in the Presence and Absence of the Substrate Uridine Diphosphoglucose
      Vrielink, A.,Rueger, W.,Driessen, H.P.C.,Freemont, P.S.
      (1994) Embo J. 13: 3413
    • T4-Induced Alpha- and Beta-Glucosyltransferase: Cloning of the Genes and a Comparison of Their Products Based on Sequencing Data
      Tomaschewski, J.,Gram, H.,Crabb, J.W.,Ruger, W.
      (1985) Nucleic Acids Res. 13: 7551


    Organizational Affiliation

    Molecular Structure and Function Laboratory, Imperial Cancer Research Fund, 44 Lincoln's Inn Field, London, WC2A 3PX, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
BETA-GLUCOSYLTRANSFERASE
A
351Enterobacteria phage T4Gene Names: bgt
EC: 2.4.1.27
Find proteins for P04547 (Enterobacteria phage T4)
Go to UniProtKB:  P04547
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
UDP
Query on UDP

Download SDF File 
Download CCD File 
A
URIDINE-5'-DIPHOSPHATE
C9 H14 N2 O12 P2
XCCTYIAWTASOJW-XVFCMESISA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.190 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 69.460α = 90.00
b = 102.470β = 90.00
c = 59.420γ = 90.00
Software Package:
Software NamePurpose
X-PLORphasing
X-PLORrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1999-07-28
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance