ATP hydrolytic activity was measured by following the decrease of NADH fluorescence in an enzyme-coupled assay upon excitation at 340 nm and emission at 450 nm in a temperature range from 4 to 65 °C. a, Temperature dependence of the ATPase activity of Wzm–WztN. Shown is the difference in NADH fluorescence between control reactions in the absence of Wzm–WztN and reactions in its presence. b, Hydrolytic activity of full-length Wzm–Wzt in the presence of isolated Wzt-CBD measured at 27 °C. Shown are fluorescence intensity differences (calculated as for Fig. 4b) but not converted to apparent catalytic rates. Dashed line, ATP titration in the presence of only the CBD of Wzt. Hydrolytic activity of Wzm–WztN in the absence of the CBD of Wzt is shown for comparison. c, Comparison of ATPase activities of full-length (green) and truncated (black) Wzm–Wzt. Shown are apparent catalytic rates in detergent-solubilized and liposome-reconstituted states. Data points represent the mean of three independent repeats with s.d. CPS, counts per second.