非表示:
キーワード:
Amyloid; Neurodegeneration; Metallobiology; NMR
要旨:
α-Synuclein (AS) aggregation is associated to neurodegeneration in Parkinson's disease (PD). At the same
time, alterations in metal ion homeostasis may play a pivotal role in the progression of AS amyloid assembly
and the onset of PD. Elucidation of the structural basis directing AS–metal interactions and their effect on AS
aggregation constitutes a key step towards understanding the role of metal ions in AS amyloid formation and
neurodegeneration. Despite of the reported evidences that link Zn2+ with the pathophysiology of PD and the
fact that this metal ion was shown to promote AS fibrillation in vitro, neither the structural characterization
of the binding sites nor the identification of the amino acids involved in the interaction of Zn2+ with the protein
AS has been carried out. By using NMR spectroscopy, we have addressed here unknown structural details
related to the binding of Zn2+ to the protein AS through the design of site-directed and domain truncated
mutants of AS. The binding of zinc to the Aβ peptide was also studied and discussed comparatively. Although
the results of this study contribute to the understanding of the structural and molecular basis behind the acceleration
of AS fibrillation mediated by Zn2+, the low affinity that characterizes the interaction of Zn2+ with
AS contrasts strongly with the high-affinity features reported for the binding of this metal ion to other target
proteins linked to human amylodosis such as Aβ peptide and the Islet Amyloid Polypeptide (IAPP), challenging
the biological relevance of zinc interactions in the pathogenesis of PD.
