CONTROL OF SYNTHESIS OF REACTION CENTER BACTERIOCHLOROPHYLL IN PHOTOSYNTHETIC BACTERIA

Abstract— The ratio of total bacteriochlorophyll (BChl) to reaction center BChl has been determined in the wild‐type and carotenoid‐less mutants of Rhodopseudomonas spheroides and Rhodospirillum rubrum with various specific BChl contents. In wild‐type R. spheroides the ratio increases as the specific BChl content increases; in the other strains the ratio is almost invariant. The ability of the wild‐type of R. spheroides to alter the size of the photosynthetic unit is apparently correlated with its multi‐component BChl spectrum. The amount of reaction center BChl relative to the amount of the longest wavelength component of the spectrum is constant. The variation in the size of the photosynthetic unit is due to variation in the amount of this component relative to total BChl. The size of the photosynthetic unit does not change as the specific BChl content decreases during growth under aerobic conditions of a culture grown previously under photosynthetic conditions.