FIGURE 2.
Comparison of glycine betaine uptake for parental OpuA and CBS deletion mutants: OpuA (•), OpuAΔ119 (▾), and OpuAΔ61 (○). The purified proteins were reconstituted in proteoliposomes, composed of 50 mol % DOPE, 12 mol % DOPC, and 38 mol % DOPG. The lumen of the vesicles contained 9 mm Na2-ATP, 9 mm MgSO4, and 10 mm potassium Pi, pH 7.0, which was enclosed by 2 cycles of freeze-thawing. Uptake of [14C]glycine betaine was assayed in 30 mm potassium Pi, pH 7.0, with or without added KCl as indicated on the x axis.