Thermostability of MelBSt solubilised in M-XMAs or P-XMA-C11. E. coli membranes containing MelBSt were treated with detergent (1.5%, w/v) for 90 min at 0, 45, 55, or 65 °C. The amounts of soluble MelBst after ultracentrifugation were estimated by A) SDS-PAGE and western blotting, then B) expressed as histograms (percentage of total MelBSt in untreated membrane sample). Band densities were measured by ImageQuant software (mean ± SEM, n=2–4).