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Structure and topology of the non‐amyloid‐β component fragment of human α‐synuclein bound to micelles: Implications for the aggregation process
Author(s) -
Bisaglia Marco,
Trolio Alessandra,
Bellanda Massimo,
Bergantino Elisabetta,
Bubacco Luigi,
Mammi Stefano
Publication year - 2006
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.052048706
Subject(s) - alpha synuclein , micelle , chemistry , biophysics , peptide , amyloid (mycology) , fibril , topology (electrical circuits) , peptide sequence , protein aggregation , biochemistry , biology , parkinson's disease , gene , medicine , disease , inorganic chemistry , mathematics , pathology , combinatorics , aqueous solution
Abstract Human α‐synuclein is a small soluble protein abundantly expressed in neurons. It represents the principal constituent of Lewy bodies, the main neuropathological characteristic of Parkinson's disease. The fragment corresponding to the region 61–95 of the protein, originally termed NAC ( n on‐ a myloid‐β c omponent), has been found in amyloid plaques associated with Alzheimer's disease, and several reports suggest that this region represents the critical determinant of the fibrillation process of α‐synuclein. To better understand the aggregation process of α‐synuclein and the role exerted by the biological membranes, we studied the structure and the topology of the NAC region in the presence of SDS micelles, as membrane‐mimetic environment. To overcome the low solubility of this fragment, we analyzed a recombinant polypeptide corresponding to the sequence 57–102 of α‐synuclein, which includes some charged amino acids flanking the NAC region. Three distinct helices are present, separated by two flexible stretches. The first two helices are located closer to the micelle surface, whereas the last one seems to penetrate more deeply into the micelle. On the basis of the structural and topological results presented, a possible pathway for the aggregation process is suggested. The structural information described in this work may help to identify the appropriate target to reduce the formation of pathological α‐synuclein aggregation.