Abstract
The assembly of photosystem II (PSII) complex has been studied, especially in rapid turnover of photodamaged D1 protein in photoinhibition. However, there is still much to be learned about molecular mechanism and pathway of the PSII assembly. We have analyzed structure and function of the PSII subunits by using Synechocystis sp. PCC 6803 and the thermophilic cyanobacteria, Thermosysnechococcus elongatus BP-1 and T. vulcanus. We have prepared various PSII complexes lacking PSII subunits such as PsbX, PsbI, PsbK, PsbTc, PsbH, PsbM, and PsbZ. PsbI, PsbK, PsbTc, PsbH, and PsbM are important for the stability of dimeric PSII complexes. Deletion of psbTc resulted in loss of PsbM and deletion of psbH resulted in loss of PsbX in the PSII complex. We are now studying crystal structure of psbTc and psbM mutants. We recently found a gene involved in destabilization of PSII. We will discuss assembly and stabilization of PSII complex of cyanobacteria.
