Activity Regulation Of Chloroplast ATP Synthase And Site-directed Mutangenesis Of Its Subunit

Chloroplast ATP synthase is one of the four super membrane-protein complexes in thylakoid membranes of higher plants. The enzyme is a multisubunit complex with distinct stromal and transmembrane regions that are know as CF1 and CF0, respectively. ATP synthase is a key enzyme of photosynthetic energy conversion, which catalyzses ATP synthesis using a transmembrane proton motive force that is generated by the proton translocation coupling of the photosynthetic electron transport. Further study on ATP synthase have significance in bioenergetics. The main reasech of this thesis is the improvement of tetracycline on photophosphorylation and its action site on ATP synthase, as well as structure and function study on the important εsubunit of the synthase by using the site-directed mutangenesis method. 1. The first study investigated the effects of tetracycline on photophosphorylation, electron transport and P/O ratio of spinach chloroplasts. When chloroplast preparations were treated with low concentrations of tetracycline, non-cyclic and cyclic photophosphorylation activities of the chloroplast increased, electron transport rates and P/O ratios improved, chloroplast ms-DLE also improved, and the Mg2+-ATPase activity of CF1 increased in comparison to the control. These results indicate that spinach chloroplasts are sensitive to tetracycline. Next, we used the fluorescence emission spectra of CF1 to examine the possible binding sites for tetracycline. The fluorescence emission spectra of CF1 treated with glutaraldehyde, NEM and TNBS, which interact with CF1 across its whole structure, at the γsubunit and at the βsubunit, respectively, were compared with that of control CF1. The peak sites of the various fluorescence emission spectra were the same, but the peak...