The atp1 and atp2 operons of the cyanobacterium Synechocystis sp. PCC 6803

The two operons atp1 and atp2, encoding the subunits of the F_OF₁ ATP-synthase, have been cloned and sequenced from the cyanobacterium Synechocystis sp. PCC 6803. The organization of the different genes in the operons have been found to resemble that of the cyanobacteria Synechococcus sp. PCC 6301 and Anabaena sp. PCC 7120. The Synechocystis F_OF₁ ATP-synthase has nine subunits. A tenth open reading frame with unknown function was detected at the 5′ end of atp1, coding for a putative gene product similar to uncI in Escherichia coli. A promoter structure was inferred for the Synechocystis atp operons and compared to other known promoters of cyanobacteria. Even though the operon structure of atp1 and atp2 in Synechocystis resembles the corresponding operons of Synechococcus, the amino acid sequences of individual gene products show marked differences. Genetic distances between cyanobacterial genes and genes for ATP-synthase subunits from other species have been calculated and compiled into evolutionary trees.