1PZT

CRYSTAL STRUCTURE OF W314A-BETA-1,4-GALACTOSYLTRANSFERASE (B4GAL-T1) CATALYTIC DOMAIN WITHOUT SUBSTRATE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The role of tryptophan 314 in the conformational changes of beta1,4-galactosyltransferase-I

Ramasamy, V.Ramakrishnan, B.Boeggeman, E.Qasba, P.K.

(2003) J.Mol.Biol. 331: 1065-1076

  • Primary Citation of Related Structures:  1PZY

  • PubMed Abstract: 
  • beta1,4-Galactosyltransferase-I (beta4Gal-T1) undergoes critical conformational changes upon substrate binding from an open conformation (conf-I) to the closed conformation (conf-II). This change involves two flexible loops: the small (residues 313-3 ...

    beta1,4-Galactosyltransferase-I (beta4Gal-T1) undergoes critical conformational changes upon substrate binding from an open conformation (conf-I) to the closed conformation (conf-II). This change involves two flexible loops: the small (residues 313-316) and the long loop (residues 345-365). Upon substrate binding, Trp314 in the small flexible loop moves towards the catalytic pocket and interacts with the donor and the acceptor substrates. For a better understanding of the role played by Trp314 in the conformational changes of beta4Gal-T1, we mutated it to Ala and carried out substrate-binding, proteolytic and crystallographic studies. The W314A mutation reduces the enzymatic activity, binding to substrates and to the modifier protein, alpha-lactalbumin (LA), by over 99%. The limited proteolysis with Glu-C or Lys-C proteases shows differences in the rate of cleavage of the long loop of the wild-type and mutant W314A, indicating conformational differences in the region between the two proteins. Without substrate, the mutant crystallizes in a conformation (conf-I') (1.9A resolution crystal structure), that is not identical with, but close to an open conformation (conf-I), whereas its complex with the substrates and alpha-lactalbumin, crystallizes in a conformation (2.3A resolution crystal structure) that is identical with the closed conformation (conf-II). This study shows the crucial role Trp314 plays in the conformational state of the long loop, in the binding of substrates and in the catalytic mechanism of the enzyme.


    Organizational Affiliation

    Structural Glycobiology Section, LECB, CCR, NCI-Frederick, Building 469, Room 221, 21702, Frederick, MD, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Beta-1,4-galactosyltransferase 1
A
286Bos taurusGene Names: B4GALT1 (GALT, GGTB2)
EC: 2.4.1.22, 2.4.1.38, 2.4.1.90, 2.4.1.-
Find proteins for P08037 (Bos taurus)
Go to Gene View: B4GALT1
Go to UniProtKB:  P08037
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.189 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 92.199α = 90.00
b = 39.301β = 108.07
c = 78.539γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
AMoREphasing
CNSrefinement
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-09-16
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance