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Effects of Mutations on the Reconfiguration Rate of α-Synuclein

Author:
Acharya, Srabasti, Saha, Shreya, Ahmad, Basir, Lapidus, Lisa J.
Source:
The Journal of physical chemistry 2015 v.119 no.50 pp. 15443-15450
ISSN:
1520-5207
Subject:
neurodegenerative diseases, oligomerization, pH, physical chemistry, point mutation, temperature
Abstract:
It is still poorly understood why α-synuclein, the intrinsically disordered protein involved in Parkinson’s and other neurodegenerative diseases, is so prone to aggregation. Recent work has shown a correlation between the aggregation rate and the rate of diffusional reconfiguration by varying temperature and pH. Here we examine the effects of several point mutations in the sequence on the conformational ensemble and reconfiguration rate. We find that at lower temperatures the PD causing aggregation enhancing mutations slow down and aggregation reducing mutations drastically speed up intramolecular diffusion, as compared to the wild type sequence. However, at higher temperatures, one of three familial mutations that enhance aggregation slows intramolecular diffusion while non-natural mutations that inhibit aggregation speed up intramolecular diffusion. These results support the hypothesis that the first step of aggregation is kinetically controlled by reconfiguration in which the protein chain cannot reconfigure rapidly enough to escape oligomerization. Finally we provide physical and chemical insights into why small point mutations cause these dramatic changes in the conformational ensemble and dynamics.
Agid:
5614163