Single-Molecule FRET States, Conformational Interchange, and Conformational Selection by Dye Labels in Calmodulin.

ABSTRACT: We investigate the roles of measurement time scale and the nature of the fluorophores in the FRET states measured for calmodulin, a calcium signaling protein known to undergo pronounced conformational changes. The measured FRET distributions depend markedly on the measurement time scale (nanosecond or microsecond). Comparison of FRET distributions measured by donor fluorescence decay with FRET distributions recovered from single-molecule burst measurements binned over time scales of 90 μs to 1 ms reveals conformational averaging over the intervening time regimes. We find further that, particularly in the presence of saturating Ca(2+), the nature of the measured single-molecule FRET distribution depends markedly on the identity of the FRET pair. The results suggest interchange between confo

SUBMITTER: DeVore MS 

PROVIDER: S-EPMC4894822 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature