Abstract
The RCs of purple bacteria and FAPs are similar to each other, and seemed to have derived from a common ancestral protein. The puf genes form one operon puf B-A-L-M-C in purple bacteria and R.castenholzii (FAP), while form two operons, pufB-A-C and pufL-M, in another FAP, Chloroflexus aurantiacus. This feature of R.castenholzii seemed to reflect that of the common ancestor. To obtain more information of photosynthetic genes of the common ancestor, we studied the transcriptional organization of the puf operon in R.castenholzii. In northern hybridization experiments, small amounts of 3.5kb (pufBALMC) and 2kb (pufBALM) mRNAs, and a large amount of 0.3kb (pufBA) mRNA were detected as in the case of purple bacteria. 5'end of these mRNAs were detected at the 140 base upstream of the pufB. The putative promoter sequences similar to that of Cfl.aurantiacus were detected at the corresponding position.
