ATPase and transport activities of cross-linked MalE–FGK2 supercomplexes. (A) ATPase activity of MalFG(P78C), EBS-, or PBS-linked MalFG(P78C)–MalE(G13C) (named EBS-G78-E13, PBS-G78-E13) in the presence of increasing concentration of freely diffusible MalE(G13C) and of MalFG(T46C) and PBS-linked MalFG(T46C)–MalE(S352C) (named PBS-G46-E13) in the presence of increasing concentration of freely diffusible MalE(S352C). (B) [14C]maltose transport of reconstituted MalFG(P78C) and MalFG(T46C) with added MalE(G13C) and MalE(S352C), respectively, at molar ratios 10:1 (gray) or 1:1 (dark gray) and of the supercomplexes EBS-G78-E13, PBS-G78-E13, and PBS-G46-E352. The asterisks in the EBS-linked supercomplex denote the observed basal maltose incorporation, with no time-dependent increase. Each value is the mean of three separate determinations with SD shown as error bars.