title: The role of the central flexible region on the aggregation and conformational properties of human ataxin-3.
abstract: Aggregation of human ataxin-3 (AT3) into amyloid fibrils is responsible for spinocerebellar ataxia type 3. This protein consists of a folded N-terminal domain (Josephin domain, residues 1-182), a central flexible region (residues 183-291), a poly-glutamine sequence of variable length and a short C-terminal flexible region. Very little is known about the influence of the central flexible region on the conformational and aggregation properties of this protein. The present study aimed to investigate the specific role of this portion of the protein (residues 183-291). Accordingly, protein fragments 1-182 (AT3/182) and 1-291 (AT3/291) were produced and compared by thioflavin-T fluorescence, Fourier transform infrared spectroscopy, CD, intrinsic fluorescence and ESI-MS. It is shown that the central flexible region enhances protein aggregation and can populate conformational states with different degrees of compactness. Both monomeric and dimeric partially-folded forms are identified for both protein fragments under denaturing conditions. Partially-folded monomers and dimers accumulate to a larger extent in AT3/291. These species represent good candidates for early intermediates of the aggregation process under the experimental conditions employed in the present study.
authors: Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy.
authors: Carlo
authors: C
authors: Santambrogio
authors: Anna M
authors: AM
authors: Frana
authors: Antonino
authors: A
authors: Natalello
authors: Elena
authors: E
authors: Papaleo
authors: Maria E
authors: ME
authors: Regonesi
authors: Silvia M
authors: SM
authors: Doglia
authors: Paolo
authors: P
authors: Tortora
authors: Gaetano
authors: G
authors: Invernizzi
authors: Rita
authors: R
authors: Grandori
mesh_terms: D000595:Amino Acid Sequence; D000067699:Ataxin-3; D006801:Humans; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry*; D009687:Nuclear Proteins / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry*; D017510:Protein Folding; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010446:Peptide Fragments; D012097:Repressor Proteins; C092341:ATXN3 protein, human; D000067699:Ataxin-3