Abstract
Chloroplast F1 (CF1) equips several regulation mechanisms; redox regulation, the specific inhibition and acceleration by phytotoxic tentoxin, and inhibition by the internal inhibitory subunit epsilon. In order to investigate these regulation mechanisms thoroughly, we constructed the expression system for the subcomplex of F1-ATPase from cyanobacteria Thermosynechococcus elongatus BP-1 (TSF1). In addition, we successfully introduced the regulatory region of the gamma subunit of the chloroplast CF1 into the gamma subunit of this complex (TSF1-redox). ATP hydrolysis activity of the obtained TSF1-redox was nicely redox regulated. The effect of tentoxin to TSF1 was similar to that for CF1. Hence TSF1 and TSF1-redox mimic many features of CF1, and they will be a useful tool for the study on the regulation mechanisms of CF1 at the single molecule level. The inhibitory effect of the epsilon subunit on rotation of the gamma subunit will be also discussed.
