In an Experiment to Investigate the Folding of Tethered Labelled

Multiple Choice

In an experiment to investigate the folding of tethered labelled peptides using fluorescence resonant energy transfer, the quantum yield for fluorescence of a rhodamine dye donor was found to decrease, on average, by a factor of 0.21 in the presence of a Texas red dye acceptor. Use the Förster theory of resonant energy transfer to determine the separation of the donor-acceptor pair, given that the Förster distance parameter for the rhodamine-Texas red pair is R₀ = 4.4 nm.

A) 4.4 nm
B) 3.5 nm
C) 21.0 nm
D) 0.86 nm