5TJH

hUGDH A136M Substitution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.171 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Allostery and Hysteresis Are Coupled in Human UDP-Glucose Dehydrogenase.

Beattie, N.R.Keul, N.D.Sidlo, A.M.Wood, Z.A.

(2017) Biochemistry 56: 202-211

  • DOI: 10.1021/acs.biochem.6b01044

  • PubMed Abstract: 
  • Human UDP-glucose dehydrogenase (hUGDH) is regulated by an atypical allosteric mechanism in which the feedback inhibitor UDP-xylose (UDP-Xyl) competes with the substrate for the active site. Binding of UDP-Xyl triggers the T131-loop/α6 allosteric swi ...

    Human UDP-glucose dehydrogenase (hUGDH) is regulated by an atypical allosteric mechanism in which the feedback inhibitor UDP-xylose (UDP-Xyl) competes with the substrate for the active site. Binding of UDP-Xyl triggers the T131-loop/α6 allosteric switch, which converts the hexameric structure of hUGDH into an inactive, horseshoe-shaped complex (EΩ). This allosteric transition buries residue A136 in the protein core to produce a subunit interface that favors the EΩ structure. Here we use a methionine substitution to prevent the burial of A136 and trap the T131-loop/α6 switch in the active conformation. We show that hUGDHA136M does not exhibit substrate cooperativity, which is strong evidence that the methionine substitution prevents the formation of the low-UDP-Glc-affinity EΩ state. In addition, the inhibitor affinity of hUGDHA136M is reduced 14-fold, which most likely represents the Ki for competitive inhibition in the absence of the allosteric transition to the higher-affinity EΩ state. hUGDH also displays a lag in progress curves, which is caused by a slow, substrate-induced isomerization that activates the enzyme. Stopped-flow analysis shows that hUGDHA136M does not exhibit hysteresis, which suggests that the T131-loop/α6 switch is the source of the slow isomerization. This interpretation is supported by the 2.05 Å resolution crystal structure of hUGDHA136M, which shows that the A136M substitution has stabilized the active conformation of the T131-loop/α6 allosteric switch. This work shows that the T131-loop/α6 allosteric switch couples allostery and hysteresis in hUGDH.


    Organizational Affiliation

    Department of Biochemistry & Molecular Biology, University of Georgia , Athens, Georgia 30602, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
UDP-glucose 6-dehydrogenase
A, B, C, D, E, F
494Homo sapiensMutation(s): 1 
Gene Names: UGDH
EC: 1.1.1.22
Find proteins for O60701 (Homo sapiens)
Go to Gene View: UGDH
Go to UniProtKB:  O60701
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
POP
Query on POP

Download SDF File 
Download CCD File 
A, B, D, E, F
PYROPHOSPHATE 2-
H2 O7 P2
XPPKVPWEQAFLFU-UHFFFAOYSA-L
 Ligand Interaction
UPG
Query on UPG

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

Download SDF File 
Download CCD File 
B, D
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.203 
  • R-Value Work: 0.171 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 92.350α = 64.82
b = 104.590β = 68.35
c = 107.710γ = 73.72
Software Package:
Software NamePurpose
PHASERphasing
XDSdata scaling
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical SciencesUnited States--

Revision History 

  • Version 1.0: 2016-11-02
    Type: Initial release
  • Version 1.1: 2017-01-04
    Type: Database references
  • Version 1.2: 2017-01-25
    Type: Database references
  • Version 1.3: 2017-09-27
    Type: Author supporting evidence, Refinement description