Fig. 3.

Reverse methyltransferase activity in the direction of CH₃-tetrahydrofolate production driven by a sodium gradient dependent on reduced ferredoxin:Fe(III) oxidoreductase activity. The standard reaction mixture (1.0 ml) contained Fe(III)-loaded vesicles (1.0 mg protein), 2.0 mM CH₃-SCoM (methyl-coenzyme M), 2.0 mM THF (tetrahydrofolate), 5.0 µM Fdx (ferredoxin), 25 mM MgSO₄, 0.4 M sucrose and 0.5 mM residual NaCl in 20 mM Tris (pH 7.0) and 1.0 atmosphere of CO. Reactions were initiated with CO dehydrogenase/acetyl-CoA synthase (0.1 mg). Standard reaction mixture (filled diamonds), plus 1 mM ATP (filled squares), plus 10 µM carbonyl cyanide m-chlorophenyl hydrazine (CCCP) (filled triangles), plus 10 µM ETH157 (filled circles), minus Fdx (empty squares), with empty vesicles (empty diamonds), minus CH₃-SCoM (empty circles), minus THF (empty triangles). Data points are the mean of three biological replicates for which the standard deviation is shown by the error bars