Control of Photosystem Formation in Rhodobacter sphaeroides

Control of photosystem formation in Rhodobacter sphaeroides.

Identification and in vivo characterization of PpaA, a regulator of photosystem formation in Rhodobacter sphaeroides.

A regulatory protein, PpaA, involved in photosystem formation in the anoxygenic phototrophic proteobacterium Rhodobacter sphaeroides has been identified and characterized in vivo. Based on the phenotypes of cells expressing the ppaA gene in extra copy and on the phenotype of the ppaA null mutant, it was concluded that PpaA activates photopigment production and puc operon expression under aerobi...

Osmoregulation in Rhodobacter sphaeroides.

Betaine (N,N,N-trimethylglycine) functioned most effectively as an osmoprotectant in osmotically stressed Rhodobacter sphaeroides cells during aerobic growth in the dark and during anaerobic growth in the light. The presence of the amino acids L-glutamate, L-alanine, or L-proline in the growth medium did not result in a significant increase in the growth rate at increased osmotic strengths. The...

Complexes of Rhodobacter sphaeroides and Rhodobacter capsulatus

Photosynthetic bacteria offer excellent experimental opportunities to explore both the structure and function of the ubiquinol-cytochrome c oxidoreductase (bcl complex). In both Rhodobacter sphaeroides and Rhodobaeter capsulatus, the bCl complex functions in both the aerobic respiratory chain and as an essential component of the photosynthetic electron transport chain. Because the bc~ complex i...

Translational control of puf operon expression in Rhodobacter sphaeroides 2.4.1.

The puf operon of Rhodobacter sphaeroides 2.4.1 encode the beta- and alpha-polypeptides of the B875 complex, the L and M polypeptides of the reaction centre and the pufX gene product. A previous report from the authors' laboratory indicated the potential existence of a 20-codon open reading frame (orfK, now designated pufK) located immediately upstream of the pufB structural gene. It is now dem...