The role of the central flexible region on the aggregation and conformational properties of human ataxin-3

TY - JOUR

T1 - The role of the central flexible region on the aggregation and conformational properties of human ataxin-3

AU - Santambrogio, Carlo

AU - Frana, Anna M

AU - Natalello, Antonino

AU - Papaleo, Elena

AU - Regonesi, Maria E

AU - Doglia, Silvia M

AU - Tortora, Paolo

AU - Invernizzi, Gaetano

AU - Grandori, Rita

N1 - © 2011 The Authors Journal compilation © 2011 FEBS.

PY - 2012/2

Y1 - 2012/2

N2 - 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.

AB - 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.

KW - Amino Acid Sequence

KW - Humans

KW - Models, Molecular

KW - Nerve Tissue Proteins

KW - Nuclear Proteins

KW - Peptide Fragments

KW - Protein Folding

KW - Protein Multimerization

KW - Protein Structure, Tertiary

KW - Repressor Proteins

KW - Spectrum Analysis

U2 - 10.1111/j.1742-4658.2011.08438.x

DO - 10.1111/j.1742-4658.2011.08438.x

M3 - Journal article

C2 - 22129356

SN - 1742-464X

VL - 279

SP - 451

EP - 463

JO - F E B S Journal

JF - F E B S Journal

IS - 3

ER -