Study On The Structure And Function Changes Of CP43 And CP47 Induced By Physical And Chemical Factors

CP43 and CP47 are the core antenna subunits of photosystem II (PSII). Both CP43 and CP47 have six transmembraneα-helices, which are separated by five extrinsic loop domains. The main function of CP43 and CP47 are to accept excitation energy that is harvested by the light-harvesting complex II (LHC II) and then transfer it directly to the PSII reaction center (RC). So, it plays a key role to study the structure and function of CP43 and CP47 for elucidating the mechanism of the efficient energy absorption and transfer in plants. Because of the difficulties in purification, relative to the other membrane proteins, few studies were focused on CP43 and CP47. In this dissertation, using some spectroscopy techniques, we further studied the structure and function changes of CP43 and CP47 by the denaturation induced by GuHCl and high temperature. The results are as follows:1 The structural characteristics of the extramembrane domains and guanidine hydrochloride-induced denaturation of Photosystem II Core antenna complexes CP43 and CP47The structure characteristics of the extramembrane domains and guanidine hydrochloride-induced denaturation of Photosystem II (PSII) core antenna complexes CP43 and CP47 were investigated using fluorescence emission and circular dichroism (CD) spectra. It was found that the extramembrane domains of CP43 and CP47 do possess a certain degree of secondary and tertiary structure and not a complete random coil conformation. The tertiary structure and the Chl a microenvironment of CP47 are more sensitive to GuHCl than that of CP43. Changes in energy transfer fromβ-Car to Chl a corresponded well to changes in the tertiary structure while their correlation with changes in the secondary structure was rather poor. Unlike most of...