3KHU

Crystal structure of human UDP-glucose dehydrogenase Glu161Gln, in complex with thiohemiacetal intermediate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.195 

wwPDB Validation   3D Report Full Report


Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Structural and Kinetic Evidence That Catalytic Reaction of Human UDP-glucose 6-Dehydrogenase Involves Covalent Thiohemiacetal and Thioester Enzyme Intermediates.

Egger, S.Chaikuad, A.Klimacek, M.Kavanagh, K.L.Oppermann, U.Nidetzky, B.

(2012) J Biol Chem 287: 2119-2129

  • DOI: 10.1074/jbc.M111.313015
  • Primary Citation of Related Structures:  
    3KHU

  • PubMed Abstract: 
  • Biosynthesis of UDP-glucuronic acid by UDP-glucose 6-dehydrogenase (UGDH) occurs through the four-electron oxidation of the UDP-glucose C6 primary alcohol in two NAD(+)-dependent steps. The catalytic reaction of UGDH is thought to involve a Cys nucleophile that promotes formation of a thiohemiacetal enzyme intermediate in the course of the first oxidation step ...

    Biosynthesis of UDP-glucuronic acid by UDP-glucose 6-dehydrogenase (UGDH) occurs through the four-electron oxidation of the UDP-glucose C6 primary alcohol in two NAD(+)-dependent steps. The catalytic reaction of UGDH is thought to involve a Cys nucleophile that promotes formation of a thiohemiacetal enzyme intermediate in the course of the first oxidation step. The thiohemiacetal undergoes further oxidation into a thioester, and hydrolysis of the thioester completes the catalytic cycle. Herein we present crystallographic and kinetic evidence for the human form of UGDH that clarifies participation of covalent catalysis in the enzymatic mechanism. Substitution of the putative catalytic base for water attack on the thioester (Glu(161)) by an incompetent analog (Gln(161)) gave a UGDH variant (E161Q) in which the hydrolysis step had become completely rate-limiting so that a thioester enzyme intermediate accumulated at steady state. By crystallizing E161Q in the presence of 5 mm UDP-glucose and 2 mm NAD(+), we succeeded in trapping a thiohemiacetal enzyme intermediate and determined its structure at 2.3 Å resolution. Cys(276) was covalently modified in the structure, establishing its role as catalytic nucleophile of the reaction. The thiohemiacetal reactive C6 was in a position suitable to become further oxidized by hydride transfer to NAD(+). The proposed catalytic mechanism of human UGDH involves Lys(220) as general base for UDP-glucose alcohol oxidation and for oxyanion stabilization during formation and breakdown of the thiohemiacetal and thioester enzyme intermediates. Water coordinated to Asp(280) deprotonates Cys(276) to function as an aldehyde trap and also provides oxyanion stabilization. Glu(161) is the Brønsted base catalytically promoting the thioester hydrolysis.


    Organizational Affiliation

    Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, A-8010 Graz, Austria.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
UDP-glucose 6-dehydrogenaseA, B, C, D, E, F467Homo sapiensMutation(s): 1 
Gene Names: UGDH
EC: 1.1.1.22
UniProt & NIH Common Fund Data Resources
Find proteins for O60701 (Homo sapiens)
Explore O60701 
Go to UniProtKB:  O60701
PHAROS:  O60701
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
UPG (Subject of Investigation/LOI)
Query on UPG

Download Ideal Coordinates CCD File 
AA [auth E] , BA [auth E] , G [auth A] , H [auth A] , IA [auth F] , JA [auth F] , L [auth B] , M [auth B] , 
AA [auth E],  BA [auth E],  G [auth A],  H [auth A],  IA [auth F],  JA [auth F],  L [auth B],  M [auth B],  S [auth C],  T [auth C],  X [auth D],  Y [auth D]
URIDINE-5'-DIPHOSPHATE-GLUCOSE
C15 H24 N2 O17 P2
HSCJRCZFDFQWRP-JZMIEXBBSA-N
 Ligand Interaction
EPE
Query on EPE

Download Ideal Coordinates CCD File 
Z [auth D]4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID
C8 H18 N2 O4 S
JKMHFZQWWAIEOD-UHFFFAOYSA-N
 Ligand Interaction
EDO
Query on EDO

Download Ideal Coordinates CCD File 
CA [auth E] , DA [auth E] , EA [auth E] , FA [auth E] , GA [auth E] , HA [auth E] , I [auth A] , J [auth A] , 
CA [auth E],  DA [auth E],  EA [auth E],  FA [auth E],  GA [auth E],  HA [auth E],  I [auth A],  J [auth A],  K [auth A],  N [auth B],  O [auth B],  P [auth B],  Q [auth B],  R [auth B],  U [auth C],  V [auth C],  W [auth C]
1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.195 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 203.54α = 90
b = 207.34β = 90
c = 93.4γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
PHASERphasing
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2009-11-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2011-12-07
    Changes: Database references
  • Version 1.3: 2012-01-11
    Changes: Database references
  • Version 1.4: 2012-02-01
    Changes: Database references