IBR   13079
INSTITUTO DE BIOLOGIA MOLECULAR Y CELULAR DE ROSARIO
Unidad Ejecutora - UE
artículos
Título:
Interaction of alpha-synuclein with divalent metal ions reveals key differences: A link between structure, binding specificity and fibrillation enhancement.
Autor/es:
BINOLFI, A.; RASIA, R.; BERTONCINI, C.; CEOLIN, M.; GRIESINGER, C.; JOVIN, T.; FERNANDEZ, C.O.
Revista:
Journal of the American Chemical Society
Referencias:
Año: 2006 vol. 128 p. 9893 - 9901
ISSN:
0002-7863
Resumen:
The aggregation of a-synuclein (aS) is characteristic of Parkinson’s disease and other neurodegenerative synucleinopathies. Interaction with metal ions affect dramatically the kinetics of fibrillation of aS in vitro and are proposed to play a potential role in vivo. We recently showed that Cu(II) binds at the N-terminus of aS with high affinity (Kd ~ 0.1 mM) and accelerates its fibrillation. In this work we have investigated the binding features of the divalent metal ions Fe(II), Mn(II), Co(II) and Ni(II), and its effects on aS aggregation. Exploiting the different paramagnetic properties of these metal ions, NMR spectroscopy provides detailed information about the protein-metal interactions at the atomic level. The divalent metal ions bind preferentially and with low affinity (mM) to the C-terminus of aS, the primary binding site being the 119DPDNEA124 motif, in which Asp121 acts as the main anchoring residue. Combined with backbone residual dipolar coupling measurements, these results suggest that metal binding is not driven exclusively by electrostatic interactions but is mostly determined by the residual structure of the C-terminus of aS. A comparative analysis with Cu(II) revealed a hierarchal effect of aS-metal(II) interactions on aS aggregation kinetics, dictated by structural factors corresponding to different protein domains. These findings reveal a strong link between the specificity of aS-metal(II) interactions and the enhancement of aggregation of AS in vitro. The elucidation of the structural basis of aS metal binding specificity is then required to elucidate the mechanism and clarify the role of metal-protein interactions in the etiology of Parkinson’s disease