Abstract
The heliobacteria are strictly anaerobic, photosynthetic bacteria that belong to Gram-positive bacteria. They are characterized by the presence of bacteriochlorophyll g as a major photosynthetic pigment and the reaction centers (RCs) of heliobacteria belong to a Fe-S type, like those of green sulfur bacteria and PSI. Fe-S type RCs are able to photoreduce NAD(P)(+) directly via ferredoxin (Fd), although it has not been proven yet in vitro in heliobacteria. We reported that isolation and purification of four ferredoxins, Fd A, Fd B, Fd C, and Fd D, from cells of Heliobacterium Heliophirum fasciatum. The absorption spectra of the purified Fds and g values of cryogenic EPR spectra were typical of those of the 2[4Fe-4S] cluster type. In this study, we investigated NADP(+) photoreduction activity and ESR spectroscopy in the presence of Fds and purified RC from H. fasciatum.
