1A9Y

UDP-GALACTOSE 4-EPIMERASE MUTANT S124A/Y149F COMPLEXED WITH UDP-GLUCOSE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Work: 0.181 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Dramatic differences in the binding of UDP-galactose and UDP-glucose to UDP-galactose 4-epimerase from Escherichia coli.

Thoden, J.B.Holden, H.M.

(1998) Biochemistry 37: 11469-11477

  • DOI: 10.1021/bi9808969
  • Primary Citation of Related Structures:  1A9Z

  • PubMed Abstract: 
  • UDP-galactose 4-epimerase catalyzes the interconversion of UDP-galactose and UDP-glucose during normal galactose metabolism. Within recent years the enzyme from Escherichia coli has been studied extensively by both biochemical and X-ray crystallograp ...

    UDP-galactose 4-epimerase catalyzes the interconversion of UDP-galactose and UDP-glucose during normal galactose metabolism. Within recent years the enzyme from Escherichia coli has been studied extensively by both biochemical and X-ray crystallographic techniques. One of several key features in the catalytic mechanism of the enzyme involves the putative rotation of a 4'-ketopyranose intermediate within the active site region. The mode of binding of UDP-glucose to epimerase is well understood on the basis of previous high-resolution X-ray crystallographic investigations from this laboratory with an enzyme/NADH/UDP-glucose abortive complex. Attempts to prepare an enzyme/NADH/UDP-galactose abortive complex always failed, however, in that UDP-glucose rather than UDP-galactose was observed binding in the active site. In an effort to prepare an abortive complex with UDP-galactose, a site-directed mutant protein was constructed in which Ser 124 and Tyr 149, known to play critical roles in catalysis, were substituted with alanine and phenylalanine residues, respectively. With this double mutant it was possible to crystallize and solve the three-dimensional structures of reduced epimerase in the presence of UDP-glucose or UDP-galactose to high resolution. This study represents the first direct observation of UDP-galactose binding to epimerase and lends strong structural support for a catalytic mechanism in which there is free rotation of a 4'-ketopyranose intermediate within the active site cleft of the enzyme.


    Organizational Affiliation

    Department of Biochemistry, University of Wisconsin-Madison 53705, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
UDP-GALACTOSE 4-EPIMERASE
A
338Escherichia coli (strain K12)Gene Names: galE (galD)
EC: 5.1.3.2
Find proteins for P09147 (Escherichia coli (strain K12))
Go to UniProtKB:  P09147
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
UPG
Query on UPG

Download SDF File 
Download CCD File 
A
URIDINE-5'-DIPHOSPHATE-GLUCOSE
URIDINE-5'-MONOPHOSPHATE GLUCOPYRANOSYL-MONOPHOSPHATE ESTER
C15 H24 N2 O17 P2
HSCJRCZFDFQWRP-JZMIEXBBSA-N
 Ligand Interaction
NAD
Query on NAD

Download SDF File 
Download CCD File 
A
NICOTINAMIDE-ADENINE-DINUCLEOTIDE
C21 H27 N7 O14 P2
BAWFJGJZGIEFAR-NNYOXOHSSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Work: 0.181 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 85.000α = 90.00
b = 85.000β = 90.00
c = 106.700γ = 120.00
Software Package:
Software NamePurpose
TNTrefinement
XCALIBREdata scaling
SAINTdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-10-21
    Type: Initial release
  • Version 1.1: 2008-03-03
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance