The expression of genes encoding proteins of B800–850 antenna pigment complex and ribosomal RNA of Rhodopseudomonas capsulata

Abstract The synthesis of the photosynthetic apparatus was induced in chemotrophically grown cultures of the wild type strain 37b4 of Rhodopseudomonas capsulata by lowering of oxygen partial pressure. In these induced but growth-limited cultures the amount of total RNA per cell increased. Using specific DNA-probes for genes of the light-harvesting complex B800–850 and for ribosomal RNA it was shown that the levels of mRNA for the proteins of the light-harvesting complex B800-850 and for ribosomal RNA increased. In the mutant strain G1pho + , missing the B800–850 complex, but synthesizing small amounts of the M r 10000 polypeptide of the complex, the B800–850-specific mRNA was not increased during induction. It is concluded that the synthesis of the B800–850 complex is under transcriptional control and that, under these conditions, the level of rRNA also increased.