Human α-synuclein is a 140-amino acid protein of unknown function abundantly expressed in the brain and found in Lewy bodies, a characteristic feature of Parkinson's disease. α-Synuclein is random in water under physiological conditions, but the first 100 residues interact with SDS micelles or acidic phospholipid small unilamellar vesicles and adopt an ordered conformation. The rest of the molecule remains disordered in the bulk of the solution. The conformation of the N-terminal portion of the molecule in lipids was described as an extended helix [Ramakrishnan, M., Jensen, P. H., and Marsh, D. (2003) Biochemistry 42, 12919−12926], as two distinct α-helices interrupted by a two-residue break [Chandra, S., Chen, X., Rizo, J., Jahn, R., and Sudhof, T. C. (2003) J. Biol. Chem. 278, 15313−15318], or as a noncanonical conformation, the α11/3 helix [Bussell, R., Jr., and Eliezer, D. (2003) J. Mol. Biol. 329, 763−778]. We characterized the topology of the different regions of α-synuclein relative to the surface of SDS micelles using spin probe-induced broadening of NMR signals, 15N relaxation measurements, and fluorescence spectroscopy. Our results support the presence of two N-terminal helices, positioned on the surface of the micelle and separated by a flexible stretch. The region of residues 61−95 of the protein also adopts a helical conformation, but it is partially embedded in the micelle. These results could shed some light on the role of the membrane on the aggregation process of α-synuclein.

A Topological Model of the Interaction between alpha-Synuclein and SDS Micelles.

BISAGLIA, MARCO;TESSARI, ISABELLA;BELLANDA, MASSIMO;BERGANTINO, ELISABETTA;BUBACCO, LUIGI;MAMMI, STEFANO
2005

Abstract

Human α-synuclein is a 140-amino acid protein of unknown function abundantly expressed in the brain and found in Lewy bodies, a characteristic feature of Parkinson's disease. α-Synuclein is random in water under physiological conditions, but the first 100 residues interact with SDS micelles or acidic phospholipid small unilamellar vesicles and adopt an ordered conformation. The rest of the molecule remains disordered in the bulk of the solution. The conformation of the N-terminal portion of the molecule in lipids was described as an extended helix [Ramakrishnan, M., Jensen, P. H., and Marsh, D. (2003) Biochemistry 42, 12919−12926], as two distinct α-helices interrupted by a two-residue break [Chandra, S., Chen, X., Rizo, J., Jahn, R., and Sudhof, T. C. (2003) J. Biol. Chem. 278, 15313−15318], or as a noncanonical conformation, the α11/3 helix [Bussell, R., Jr., and Eliezer, D. (2003) J. Mol. Biol. 329, 763−778]. We characterized the topology of the different regions of α-synuclein relative to the surface of SDS micelles using spin probe-induced broadening of NMR signals, 15N relaxation measurements, and fluorescence spectroscopy. Our results support the presence of two N-terminal helices, positioned on the surface of the micelle and separated by a flexible stretch. The region of residues 61−95 of the protein also adopts a helical conformation, but it is partially embedded in the micelle. These results could shed some light on the role of the membrane on the aggregation process of α-synuclein.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11577/105637
Citazioni
  • ???jsp.display-item.citation.pmc??? 43
  • Scopus 99
  • ???jsp.display-item.citation.isi??? 98
social impact