Abstract
Sec-pathway is known to one of the main translocation pathway of some proteins in bacteria and plants. It is constituted of essential components SecA and SecYE translocon. SecA operates to translocate precursor proteins into thylakoid lumen in plants. Normally most of the organisms encode only one secA gene in its genome.
While primitive red alga Cyanidioschyzon merolae encodes two secA genes, one in the nucleus and the other in the plastid genome. Phylogenetic analysis showed that two secA genes grouped into different clusters. The purpose of this study is to clarify the differences of two SecAs. Previous study demonstrated that these two secA genes were transcribed. Two SecA proteins were purified to investigate ATPase activities and translocation assays. Now we attempt to isolate the chloroplasts and thylakoid membranes of C. merolae. Moreover substrates for each SecA proteins are searched by Pull-down assay.
