title: The 2.2-Angstrom resolution crystal structure of the carboxy-terminal region of ataxin-3.
abstract: An expansion of polyglutamine (polyQ) sequence in ataxin-3 protein causes spinocerebellar ataxia type 3, an inherited neurodegenerative disorder. The crystal structure of the polyQ-containing carboxy-terminal fragment of human ataxin-3 was solved at 2.2-Å resolution. The Atxn3 carboxy-terminal fragment including 14 glutamine residues adopts both random coil and α-helical conformations in the crystal structure. The polyQ sequence in α-helical structure is stabilized by intrahelical hydrogen bonds mediated by glutamine side chains. The intrahelical hydrogen-bond interactions between glutamine side chains along the axis of the polyQ α-helix stabilize the secondary structure. Analysis of this structure furthers our understanding of the polyQ-structural characteristics that likely underlie the pathogenesis of polyQ-expansion disorders.
authors.affiliation: Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Laboratory of Enzymology National Research Center «Kurchatov Institute»B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Russia.
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Zhemkov
authors.affiliation: Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Laboratory of Enzymology National Research Center «Kurchatov Institute»B.P. Konstantinov Petersburg Nuclear Physics Institute Gatchina Russia.
authors.forename: Anna A
authors.initials: AA
authors.lastname: Kulminskaya
authors.affiliation: Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Department of Physiology University of Texas Southwestern Medical Center Dallas TX USA.
authors.forename: Ilya B
authors.initials: IB
authors.lastname: Bezprozvanny
authors.affiliation: Laboratory of Molecular Neurodegeneration St Petersburg State Polytechnical University Russia; Department of Physiology University of Texas Southwestern Medical Center Dallas TX USA.
authors.forename: Meewhi
authors.initials: M
authors.lastname: Kim
keywords: Huntington's disease; ataxia; ataxins; polyglutamine; triplet repeat disorder