The Action Position Of The Heave Metal Silver Ion On Photosystem â…¡

The photosynthesis is the most important chemical reaction on our earth. The photosystem II (PSII) is one of the most important thylakoid-bond protein-pigment complexes. It is very significant for us to do research on PSII in order to know how to raise the efficiency of transforming light to energy and of simulating the sun energy in the future. It is well known that Ag+ is a graveness factor to the environment pollution. Our laboratory also found that AgNOs can inhibit the activity of PSII about releasing O2, however, we did not know the reason Because of these reasons we decided to further the research on the reaction of Ag+ on PSII. We purified the PSII particle, 33 kD protein and the PSII DrD2-Cyt b-559 reaction center complex of spinach (Spinacia oleracea L) and get rid of the CF ion of them. Using the method of absorption spectra, fluorescence emission spectra at room temperature and SDS-PAGE to investigate the effect of Ag+ ion on PSII. The results suggested that Ag+ can act on several places of PSII particle. In this paper, firstly, we purify PSII particle and after the treatment of AgNOs we found that absorption spectrum, fluorescence emission spectrum at room temperature decreased in evidence. The polypeptide component of PSII particle was altered, only 33 kD protein was lost partly after treatment. Secondly, PSII D1-D2-Cyt b-559 reaction center and 33 kD protein were purified and made them treated. The results suggested that treating 33 kD protein made it's absorption spectrum increase going with a absorption motion to Qy segment; fluorescence emission spectrum excitated at 278nm decreased and spectrum excitated at 295nm increased following with a dimunution. Treating PSII D1-D2-Cyt b-559 reaction center made it's Qx ofabsorption spectrum increase and Qy without distinct change; Fluorescence emission spectrums excitated at 278 and 295nm were similar with the change of 33 kD protein; Fluorescence emission spectrum excitated at 436nm increased following with a dimunution. Lastly, reconstituting PSII D1-D2-Cyt b-559 reaction center with 33 kD protein was affect by AgNOs. The results were as follows, absorption spectrum of 33 kD-D1-D2-Cyt b-559 treated with AgNO3 was like that of D1-D2-Cyt b-559 reaction center; Fluorescence emission spectrum excitated at 278 and 295nm decreased and the one which excitated at 436nm increased following with a dimunution going with a absorption motion to Qx segment. It can be concluded that the affect of AgNO3 can cause absorption spectrum, fluorescence emission spectrum of D1-D2-Cyt b-559 reaction center and 33 kD protein change distinctly respectively and that of PSII particle decreased and companied with losing of 33 kD protein partly. Ag+ can act on several positions of PSII particle.