1XEL

UDP-GALACTOSE 4-EPIMERASE FROM ESCHERICHIA COLI


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Molecular structure of the NADH/UDP-glucose abortive complex of UDP-galactose 4-epimerase from Escherichia coli: implications for the catalytic mechanism.

Thoden, J.B.Frey, P.A.Holden, H.M.

(1996) Biochemistry 35: 5137-5144

  • DOI: 10.1021/bi9601114

  • PubMed Abstract: 
  • UDP-galactose 4-epimerase is one of three enzymes in the metabolic pathway that converts galactose into glucose1-phosphate. Specifically this enzyme catalyzes the interconversion of UDP-galactose and UDP-glucose. The molecular structure of the NADH/U ...

    UDP-galactose 4-epimerase is one of three enzymes in the metabolic pathway that converts galactose into glucose1-phosphate. Specifically this enzyme catalyzes the interconversion of UDP-galactose and UDP-glucose. The molecular structure of the NADH/UDP-glucose abortive complex of the enzyme from Escherichia coli has been determined by X-ray diffraction analysis to a nominal resolution of 1.8 A and refined to an R-factor of 18.2% for all measurement X-ray data. The nicotinamide ring of the dinucleotide adopts the syn conformation in relationship to the ribose. Both the NADH and UDP-glucose are in the proper orientation for a B-side specific transfer from C4 of the sugar to C4 of the dinucleotide. Those residues implicated in glucose binding include Ser 124, tyr 149, Asn 179, Asn199, Arg 231, and Tyr 299. An amino acid sequence alignment of various prokaryotic and eukaryotic epimerases reveals a high degree of conservation with respect to those residues involved in both NADH and substrate binding. The nonstereospecificity displayed by epimerase was originally thought to occur through a simple rotation about the bond between the glycosyl C1 oxygen of the 4-ketose intermediate and the beta-phosphorous of the UDP moiety, thereby allowing the opposite side of the sugar to face the NADH. The present structure reveals that additional rotations about the phosphate backbone of UDP are necessary. Furthermore, the abortive complex model described here suggests that Ser 124 and Tyr 149 are likely to play important roles in the catalytic mechanism of the enzyme.


    Organizational Affiliation

    Institute for Enzyme Research, Graduate School, 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 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

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

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

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Download CCD File 
A
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
NAD
Query on NAD

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Download CCD File 
A
NICOTINAMIDE-ADENINE-DINUCLEOTIDE
C21 H27 N7 O14 P2
BAWFJGJZGIEFAR-NNYOXOHSSA-N
 Ligand Interaction
PEG
Query on PEG

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Download CCD File 
A
DI(HYDROXYETHYL)ETHER
C4 H10 O3
MTHSVFCYNBDYFN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 83.800α = 90.00
b = 83.800β = 90.00
c = 108.400γ = 120.00
Software Package:
Software NamePurpose
TNTrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 1996-01-25 
  • Released Date: 1997-02-12 
  • Deposition Author(s): Thoden, J., Holden, H.

Revision History 

  • Version 1.0: 1997-02-12
    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
  • Version 1.3: 2011-11-16
    Type: Atomic model