Redox properties of an H-subunit-depleted photosynthetic reaction center from Rhodopseudomonas viridis.

Recently, we reported that a H-subunit-depleted photosynthetic reaction center (RC-H) was purified from purple nonsulfer photosynthetic bacterium Rhodopseudomonas viridis (Rps. viridis) using a strong detergent sodium alkyl ether sulfate. We compared the redox properties of a native photosynthetic reaction center (RC) and RC-H of Rps. viridis. In RC-H prepared by our method, secondary quinone (QB) was removed while primary quinone (QA) was retained. Absorption spectrum of RC-H was similar to that of RC. After reconstitution of ubiquinone 10 into QB sites, RC-H showed electron transfer activity that was the same as that for native RC. This is the first report about the redox properties of RC-H of Rps. viridis.