The synthesis of 5,6-dimethylbenzimidazole (DMB), the lower ligand of coenzyme B(12), has remained elusive. We report in vitro and in vivo evidence that the BluB protein of the photosynthetic bacterium Rhodospirillum rubrum is necessary and sufficient for catalysis of the O(2)-dependent conversion of FMNH(2) to DMB. The product of the reaction (DMB) was isolated by using reverse-phase high-pres...

Chromatophores isolated from photosynthetic bacteria contain a disulfide-bonded repeating antigenic substructure that is serologically specific and present on the cell particles only during photosynthetic growth (l-3). This finding suggests that the structural antigen may also be a functional part of the photosynthetic electron transport system. This suggestion has been explored and supported b...