4BC3

Crystal structure of human D-xylulokinase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.68 Å
  • R-Value Free: 0.184 
  • R-Value Work: 0.159 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structure and Function of Human Xylulokinase, an Enzyme with Important Roles in Carbohydrate Metabolism

Bunker, R.D.Bulloch, E.M.M.Dickson, J.M.J.Loomes, K.M.Baker, E.N.

(2013) J.Biol.Chem. 288: 1643

  • DOI: 10.1074/jbc.M112.427997
  • Primary Citation of Related Structures:  4BC2, 4BC4, 4BC5

  • PubMed Abstract: 
  • D-Xylulokinase (XK; EC 2.7.1.17) catalyzes the ATP-dependent phosphorylation of d-xylulose (Xu) to produce xylulose 5-phosphate (Xu5P). In mammals, XK is the last enzyme in the glucuronate-xylulose pathway, active in the liver and kidneys, and is lin ...

    D-Xylulokinase (XK; EC 2.7.1.17) catalyzes the ATP-dependent phosphorylation of d-xylulose (Xu) to produce xylulose 5-phosphate (Xu5P). In mammals, XK is the last enzyme in the glucuronate-xylulose pathway, active in the liver and kidneys, and is linked through its product Xu5P to the pentose-phosphate pathway. XK may play an important role in metabolic disease, given that Xu5P is a key regulator of glucose metabolism and lipogenesis. We have expressed the product of a putative human XK gene and identified it as the authentic human d-xylulokinase (hXK). NMR studies with a variety of sugars showed that hXK acts only on d-xylulose, and a coupled photometric assay established its key kinetic parameters as K(m)(Xu) = 24 ± 3 μm and k(cat) = 35 ± 5 s(-1). Crystal structures were determined for hXK, on its own and in complexes with Xu, ADP, and a fluorinated inhibitor. These reveal that hXK has a two-domain fold characteristic of the sugar kinase/hsp70/actin superfamily, with glycerol kinase as its closest relative. Xu binds to domain-I and ADP to domain-II, but in this open form of hXK they are 10 Å apart, implying that a large scale conformational change is required for catalysis. Xu binds in its linear keto-form, sandwiched between a Trp side chain and polar side chains that provide exquisite hydrogen bonding recognition. The hXK structure provides a basis for the design of specific inhibitors with which to probe its roles in sugar metabolism and metabolic disease.


    Organizational Affiliation

    Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
XYLULOSE KINASE
A, B, C
538Homo sapiensGene Names: XYLB
EC: 2.7.1.17
Find proteins for O75191 (Homo sapiens)
Go to Gene View: XYLB
Go to UniProtKB:  O75191
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EDO
Query on EDO

Download SDF File 
Download CCD File 
A, B, C
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B, C
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.68 Å
  • R-Value Free: 0.184 
  • R-Value Work: 0.159 
  • Space Group: P 32
Unit Cell:
Length (Å)Angle (°)
a = 99.790α = 90.00
b = 99.790β = 90.00
c = 157.540γ = 120.00
Software Package:
Software NamePurpose
Aimlessdata scaling
XDSdata reduction
BUSTERrefinement
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-11-28
    Type: Initial release
  • Version 1.1: 2012-12-05
    Type: Database references
  • Version 1.2: 2013-01-30
    Type: Database references
  • Version 1.3: 2013-02-13
    Type: Database references