Visualizing a one-way protein encounter complex by ultrafast single-molecule mixing.

Abstract

We combined rapid microfluidic mixing with single-molecule Förster Resonance Energy Transfer to study the folding kinetics of the intrinsically disordered human protein α-synuclein. The time-resolution of 0.2 ms revealed initial collapse of the unfolded protein induced by binding with lipid-mimics and subsequent rapid formation of transient structures within the encounter complex. The method also enabled study of rapid dissociation and unfolding of weakly bound complexes triggered by massive dilution.