Effect of Oxygen on Translation and Posttranslational Steps in Expression of Photosynthesis Genes in Rhodobacter capsulatus

The formation of the photosynthetic apparatus in Rhodobacter capsulatus is regulated by oxygen tension. Previous studies have shown a regulatory effect of oxygen on the transcription of photosynthesis genes and on the stability of certain mRNA segments. Here we show that oxygen affects puf and puc gene expression posttranslationally and that this regulation depends on the presence of bacteriochlorophyll. Our data suggest that this posttranslational effect of oxygen on puf and puc expression is due to the primary effect of oxygen on bacteriochlorophyll synthesis or assembly of pigment protein complexes. Oxygen does not affect the rates of translation of puf-encoded proteins.