Fig. 2. Time trace of Trp→D²G FRET.

With excitation wavelength of 290 nm, emission was recorded at 465 nm for MelB_Ec or 490 nm for MelB_St. 10 μM D²G, 20 mM NaCl, melibiose (Mel, black) or water (red) were successively added at a 60-sec intervals. Left column, recorded with RSO vesicles; middle and right columns, recorded with RSO vesicles after solubilization with 1% UDM or 1% MNG-3, respectively. (a) R141K and R363K MelB_St mutants; (b) R141C, R295C, and R363C MelB_St mutants.