Expression, purification, and optimal conditions for the time- and dose-dependant ATPase FliI. A: GST-FliI eluted off a glutathione column (1 mL aliquots) and electrophoresed on an 11% SDS-PAGE gel and either probed for by anti-GST Western blot (left) or stained by Coomassie blue (right). GST-FliI migrated at approximately 73 kDa, its predicated molecular mass. Numbers refer to the eluted fraction. B: i) Time course of purified GST-FliI ATP hydrolysis (diamonds) and GST-CopN ATP hydrolysis as a negative control (squares). ii) Inorganic phosphate released at different concentrations of GST-FliI (diamonds) and GST-CopN as a negative control (squares) iii) GST-FliI ATPase activity at either 4°C, 16°C, 23°C, 37°C or 42°C. iv) GST-FliI ATPase activity at varying pH.