Differential regulation of soluble and membrane-bound inorganic pyrophosphatases in the photosynthetic bacterium Rhodospirillum rubrum provides insights into pyrophosphate-based stress bioenergetics.

ABSTRACT: Soluble and membrane-bound inorganic pyrophosphatases (sPPase and H(+)-PPase, respectively) of the purple nonsulfur bacterium Rhodospirillum rubrum are differentially regulated by environmental growth conditions. Both proteins and their transcripts were found in cells of anaerobic phototrophic batch cultures along all growth phases, although they displayed different time patterns. However, in aerobic cells that grow in the dark, which exhibited the highest growth rates, Northern and Western blot analyses as well as activity assays demonstrated high sPPase levels but no H(+)-PPase. It is noteworthy that H(+)-PPase is highly expressed in aerobic cells under acute salt stress (1 M NaCl). H(+)-PPase was also present in anaerobic cells growing at reduced rates in the dark under either fermentat

SUBMITTER: Lopez-Marques RL 

PROVIDER: S-EPMC490873 | biostudies-literature | 2004 Aug

REPOSITORIES: biostudies-literature