Fig. 6. (a) Thermo-stability of MelB_St solubilized in A-MNGs, MNG-10,10 or DDM. E. coli membranes containing MelB_St were incubated with 1.5 wt% individual detergents for 90 min at four different temperatures (0, 45, 55, and 65 °C). The protein samples solubilized by the individual detergents were analysed by SDS-PAGE and Western blotting. The amount of soluble MelB_St in each sample was estimated from gel image analysis and expressed as a percentage of the total amount of MelB_St in the untreated membrane (Total) in the histogram. Error bars, SEM; n = 2–4. (b) MelB functional assay. Right-side-out (RSO) membrane vesicles containing MelB_St or MelB_Ec were treated with DDM, MNG-9,11, or MNG-2,18 and the resulting MelB extracts after ultracentrifugation were then subjected to a functional assay (i.e., melibiose reversal of FRET from Trp to dansyl-2-galactoside (D²G)). Changes in fluorescence emission intensity were monitored following additions of D²G and an excess amount of melibiose at the 1-min and 2-min time points, respectively (magenta line). Addition of water instead of excess melibiose at the 2-min time point was used for control data (black line).