The problem of photosynthetic reaction centers has been a subject of intensive study during recent years. The interest in this subject is due to the high quantum and energetic efficiency of transforming light energy into the electrochemical potential. Up until now, grown crystals, suitable for structural investigation, provided information for only a few types of reaction centers. The reaction centers of multiheme cytochrome C complex fromRhodopseudomonas viridis1,2andRhodobacter sphaeroidasR-263,4are the most convenient for study.