Fig. 10. (a) Schematic for FRET in TBA using FurG as the donor (D, λ_ex = 315 nm) paired with an acceptor (A, λ_em = 470 nm) in the G-tetrad. (b) Structure of the A probe vBthG. (c) Emission spectra (λ_ex = 315 nm) of mTBA in K⁺-solution with FurG (D, syn-G₁₀) in the absence (blue trace) and presence (red trace) of vBthG (A, syn-G₅) for a FRET efficiency of 88% in the antiparallel GQ. (d) Thrombin emission titration with mTBA (D/A, 10; 5) with λ_ex = 315 nm.