Abstract
The typical dinoflagellate plastid has Chl a, Chl c2, and peridinin. Like brown alga and diatom, peridinin-containing dinoflagellate was suggested to have acquired its plastid from the red algae through the secondary symbiosis. Plastid genome of the dinoflagellate is consisted of separate plasmid-like molecules encoding single gene. To clarify features of the dinoflagellate PSII core proteins, two dinoflagellate strains and diverse oxygen-evolving photoautotrophs were compared using sequences of psbA/D. Our results determined that 1) due to RNA editing, genomic and complementary DNA encoded different amino acid sequences, 2) the C-terminus of the D1 protein, a critical region in Mn4Ca-cluster, was conserved, but lacks C-terminal extension involved in systematic assembly of PSII, 3) about 25% (D1) and 20% (D2) of sequence were different between the dinoflagellate and Synechocystis sp. PCC6803. Mutations were localized at the regions involved in the turnover of D1 protein or QB function.
