Abstract
The chloroplast ATP synthase (CFoCF1) is modulated by the reduction/oxidation of the two regulatory cysteines on the γ subunit. They are located in the CF1 specific regulatory region, which is composed of about 35-amino-acid residues. We previously reported that the deletion of three negative charged residues (ΔGlu210-Asp211-Glu212) inverted redox regulation of the chimera complex, which was reconstituted from the αβ subunits from thermophilic bacterium F1 (TF1) and γ from CF1.
To investigate regulation of the rotation of γ, we introduced the ΔGlu210-Asp211-Glu212 mutation into the regulatory region of α3β3γTCT complex in which the central half of γ was substituted with that from CF1-γ including the regulatory region. The desired complex was stably expressed and the ATP-hydrolyzing activity was attenuated by reduction, indicating inverse regulation. We report the results from the single molecule analysis of the rotation and discuss the redox regulation in the light of the possible conformational change of γ.