Abstract
3,8-Divinyl-chlorophyllide reductase reduces the vinyl group on the pyrrole ring B of tetrapyrrole molecules. Previously, we identified a divinyl reductase gene (DVR) from Arabidopsis thaliana by the means of genetics. However, DVR homologs were not found in most of the cyanobacterial group except five Synechococcus species. In this study, we identified cyanobacterial DVR by the combination of a bioinformatics approach and reverse genetics. We developed a bioinformatics tool to determine the species specific genes. By this tool, we found two genes were present only in the genomes which contain no Arabidopsis DVR homologs. We disrupted one of the two genes (slr1923) in Synechocystis sp. PCC6803, and found that the mutant cells accumulated divinyl chlorophyll instead of monovinyl chlorophyll. slr1923 was homologous to the gene encoding the β subunit of F420 reducing hydrogenase in organism. We concluded that slr1923 encodes DVR in Synechocystis sp. PCC6803.
