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. Author manuscript; available in PMC: 2014 Jan 1.
Published in final edited form as: Rep Prog Phys. 2012 Dec 18;76(1):016601. doi: 10.1088/0034-4885/76/1/016601

Figure 6.

Figure 6

Measuring distance changes with one dye (Hwang et al., 2011). (a) Calibration of PIFE (protein induced fluorescence enhancement) effect as a function of distance obtained from exemplary proteins: restriction enzyme, BamHI, and a motor protein RIG-I, and comparison to FRET vs distance. (b) As RIG-I translocates on RNA-DNA duplex, fluorescence signal of a fluorophore attached to one end of the duplex changes, decreasing as the protein moves away from the fluorophore. (c) A single molecule fluorescence intensity time trace showing repetitive translocation of RIG-I observed via PIFE. (d) Time traces averaged over about 50 translocation cycles over duplexes of 20, 30, and 40 base pairs in length.