FIGURE 4.

A, ATP hydrolysis activity of the reconstituted complexes. Black (○), RbsA with liposomes; purple (●), RbsAC with ribose-free proteoliposomes; orange (×), RbsA, RbsC with ribose-free proteoliposomes and RbsB; green (♦), RbsA, RbsC with ribose-loaded proteoliposomes, RbsB; red (▴), RbsAC with ribose-loaded proteoliposomes, RbsB; blue (■), RbsA, RbsBC with ribose-loaded proteoliposomes. All experiments were performed in 20 mm HEPES, pH 7.2, 50 μm ATP, and 3 mm MgCl₂ in triplicate. Lines were produced by linear regression analysis (using Microsoft Excel), forcing the fit to go through the origin. B, RbsABC ATPase activity is inhibited by vanadate. All experiments were performed in triplicate in 20 mm HEPES, pH 7.2, 50 μm ATP, 3 mm MgCl₂, and varying concentrations of vanadate. Measurements were made with RbsB-loaded RbsAC-proteoliposomes in the presence of 0 mm vanadate (■, black line); 0.1 mm vanadate (♦, purple line), 0.2 mm vanadate (▴, blue line); 0.4 mm vanadate (●, green line); 0.8 mm vanadate (×, orange line); 1.2 mm vanadate (, red line).