A vacuolar H+-pyrophosphatase in Acetabularia acetabulum: molecular cloning and comparison with higher plants and a bacterium

Abstract

Further elucidation of the H+-PPase of A. acetabulum An almost complete cDNA clone (pPPI ( AcVP gene), 3104 bp is of great interest from an evolutionary perspective of the in length/open reading frame from 795 to 2960 bp/721 amino H+-PPases from photosynthetic bacteria to higher plants. acids with a molecular weight of 74 406) encoding Acetabularia In this report, the molecular cloning of A. acetabulum H+- H+-translocating inorganic pyrophosphatase was isolated PPase is described. The primary structure of the H+-PPase from total RNA using reverse-transcription and PCR tech- was compared with the enzymes in higher plants and in the niques. Alignments of the primary structure to that of similar photosynthetic bacterium, R. rubrum. enzmes in higher plants and Rhodospirillum rubrum revealed As shown in Fig. 1, three cDNAs, pPP1, pPP2 and pPP3 that overall similarities were around 50%, the C-terminal half was well conserved but the N-terminal half showed divergen- cies except in a postulated substrate-binding domain. By Northern analysis, about 3.2 kb RNA mainly hybridized with 5ae-untranslated region specific RNA probe of the AcVP gene.