| Abstract
| - To explore tertiary contact formation in α-synuclein, a natively unfolded protein implicated in Parkinson's disease, we have measured the rates of reaction between a powerful electron donor, the tryptophan (W) triplet excited state, and an acceptor, 3-nitro-tyrosine (Y(NO2)) in six different variants, probing loop sizes between 15 and 132 residues. Electron transfer rates decrease with loop size with the fastest contact time of 140 ns for the N-terminal pair and the slowest of 1.2 μs for the N- to C-terminal pair. Diffusion coefficients ranging from ∼2 × 10-6 to ∼10-5 cm2 s-1 were extracted from simultaneous fits of the W to Y(NO2) electron (triplet excited state) and energy transfer (singlet excited state) kinetics.
|
