MOLECULAR-CLONING OF A P-TYPE ATPASE GENE FROM THE CYANOBACTERIUM SYNECHOCYSTIS SP PCC-6803 - HOMOLOGY TO EUKARYOTIC CA2+-ATPASES

With oligonucleotide primers derived from P-type ATPase genes of different sources, a part of Synechocystis sp. PCC 6803 genomic DNA was amplified and used as hybridization probe for the Synechocystis gene, A 4.7 kb HindIII fragment was cloned and sequenced; it contains the open reading frame of the E1E2-ATPase. The Synechocystis ATPase (named PMA1) consists of 915 amino acids with a Mr of 98,902; it has ten putative transmembrane domains and contains the conserved regions a to j common to all P-type ATPases. Its amino acid sequence shows less than 20% identity to prokaryotic ATPases but about 30% identity to eukaryotic Ca2+-ATPases. An alignment to rat kidney and yeast Ca2+-ATPase protein sequences shows homology in stalk regions and transmembrane domains which are thought to be involved in calcium binding and transport; these three ATPases reveal very similar hydropathy plots and form a separate group in the phylogenetic tree of P-type ATPases. The results strongly support the assumption that PMA1 of Synechocystis is a calcium translocating ATPase, possibly involved in regulatory processes with calcium as second messenger. © 1993 Academic Press Limited.