Crystal structure of the N-acetylmannosamine kinase domain of GNE.
BACKGROUND
UDP-GlcNAc 2-epimerase/ManNAc 6-kinase, GNE, is a bi-functional enzyme that plays a key role in sialic acid biosynthesis. Mutations of the GNE protein cause sialurea or autosomal recessive inclusion body myopathy/Nonaka myopathy. GNE is the only human protein that contains a kinase domain belonging to the ROK (repressor, ORF, kinase) family.


RESULTS
We solved the structure of the GNE kinase domain in the ligand-free state. The protein exists predominantly as a dimer in solution, with small populations of monomer and higher-order oligomer in equilibrium with the dimer. Crystal packing analysis reveals the existence of a crystallographic hexamer, and that the kinase domain dimerizes through the C-lobe subdomain. Mapping of disease-related missense mutations onto the kinase domain structure revealed that the mutation sites could be classified into four different groups based on the location - dimer interface, interlobar helices, protein surface, or within other secondary structural elements.


CONCLUSIONS
The crystal structure of the kinase domain of GNE provides a structural basis for understanding disease-causing mutations and a model of hexameric wild type full length enzyme.


BACKGROUND
This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S1.
Structural Genomics Consortium, University of Toronto, Toronto, Ontario, Canada.
Yufeng
Y
Tong
Wolfram
W
Tempel
Lyudmila
L
Nedyalkova
Farrell
F
Mackenzie
Hee-Won
HW
Park
D002238:Carbohydrate Epimerases / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry; D018360:Crystallography, X-Ray / Q000379:methods; D019281:Dimerization; D006801:Humans; D008024:Ligands; D008968:Molecular Conformation; D009135:Muscular Diseases / Q000378:metabolism; D009154:Mutation; D020125:Mutation, Missense; D016366:Open Reading Frames; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D002241:Carbohydrates; D008024:Ligands; D002238:Carbohydrate Epimerases; C100033:UDP acetylglucosamine-2-epimerase