Genes encoding light-harvesting and reaction center proteins from Chromatium vinosum

Sequencing of a 3.4 kb DNA fragment isolated from the photosynthetic purple sulfur bacterium Chromatium vinosum and of PCR products has resulted in id entification of the Chr. vinosum pufL, pufM, and pufC genes, reading from t he 5' to the 3' direction, and coding, respectively, for the L, M and cytoc hrome c subunits of the reaction center of this bacterium. Other PCR produc ts have been used to obtain complete sequences for the pufB and pufA genes, located immediately upstream from pufL and encoding the apoproteins of two Chr. vinosum light-harvesting proteins. The 3'-portion of the bchZ gene, a gene that codes for a protein involved in the biosynthesis of bacteriochlo rophyll, has been located immediately upstream from pufB. A second pufB gen e, pufB2, has been located downstream from pufC, as has the 5'-portion of a second pufA gene, pufA2. The location of a second set of pufB and pufA gen es, encoding light-harvesting proteins, downstream from pufC has not previo usly been reported for any photosynthetic bacterium. Translation of the gen e sequences encoding these Chr. vinosum light-harvesting proteins reveals b oth similarities to and differences from the amino acid sequences, obtained from direct sequencing of the apoproteins, previously reported for Chr vin osum light-harvesting proteins. Translation of these gene sequences, and of those for pufL, pufM and pufC, revealed significant homology, at the amino acid level, to the corresponding peptides of photosynthetic purple non-sul fur bacteria.