CHARACTERIZATION OF THE SINGLE PSBA GENE OF PROCHLOROCOCCUS-MARINUS CCMP-1375 (PROCHLOROPHYTA)

DNA sequence, copy number, expression and phylogenetic relevance of th e psbA gene from the abundant marine prokaryote P. marinus CCMP 1375 w as analyzed. The 7 amino acids near the C-terminus missing in higher p lant and in Prochlorothrix hollandica DI proteins are present in the d erived amino acid sequence. P. marinus contains only a single psbA gen e. Thus, this organism lacks the ability to adapt its photosystem II b y replacement of one type of D1 by another, as several cyanobacteria d o. Phylogenetic trees suggested the D1-1 iso-form from Synechococcus P CC 7942 as the next related D1 protein and place P. marinus separately from Prochlorothrix hollandica among the cyanobacteria.