Evidence for dynamic interplay of different oligomeric states of UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase by biophysical methods.
J Mol Biol
; 369(3): 746-58, 2007 Jun 08.
Article
en En
| MEDLINE
| ID: mdl-17448495
ABSTRACT
The bifunctional enzyme UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) is a key enzyme for the biosynthesis of sialic acids, the terminal sugars of glycoconjugates associated with a variety of physiological and pathological processes such as cell adhesion, development, inflammation and cancer. In this study, we characterized rat GNE by different biophysical methods, analytical ultracentrifugation, dynamic light-scattering and size-exclusion chromatography, all revealing the native hydrodynamic behavior and molar mass of the protein. We show that GNE is able to reversibly self-associate into different oligomeric states including monomers, dimers and tetramers. Additionally, it forms non-specific aggregates of high molecular mass, which cannot be unequivocally assigned a distinct size. Our results also indicate that ligands of the epimerase domain of the bifunctional enzyme, namely UDP-N-acetylglucosamine and CMP-N-acetylneuraminic acid, stabilize the protein against aggregation and are capable of modulating the quaternary structure of the protein. The presence of UDP-N-acetylglucosamine strongly favors the tetrameric state, which therefore likely represents the active state of the enzyme in cells.
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Banco de datos:
MEDLINE
Asunto principal:
Fosfotransferasas (Aceptor de Grupo Alcohol)
Límite:
Animals
Idioma:
En
Revista:
J Mol Biol
Año:
2007
Tipo del documento:
Article
País de afiliación:
Alemania