Figure 5.

(A) The turning point of the theoretical acceptor window fluorescence decay based on eq 3 is sensitive to changes in the proportion of FRET to the two states available in GST-mC. (B) In numerical simulations, the turning point position decreased linearly as the fraction of interacting acceptors in the short lifetime state, f, was varied from 0 to 1. The experimentally observed turning point of 0.66(±0.02) ns therefore implied that 60(±10)% of the acceptors were in the short lifetime state, reflecting that observed with optical excitation.