Nucleotide sequence of the replication region of the marine Rhodobacter plasmid pRD31

Abstract

The minimum region required for the replication of the marine Rhodabacter endogenous plasmid pRD31 has been sequenced. This region is located on a 1367-bp HincII-PstI restriction fragment and is 62% rich in G-C base pairs. A region homologous to the bacteriophage P1 repA promoter, which overlaps two inverted repeats, has been identified. Plasmids with mutations in this 1367-bp region could not replicate in marine Rhodobacter hosts. This is the first identified replication origin of a photosynthetic bacterium.