PROPERTIES AND STRUCTURE OF FRACTIONS PREPARED FROM ANABAENA VARIABILIS BY ACTION OF TRITON X-100

Treatment of Anabaena variabilis with sonic oscillation produces green membrane fragments which are derived from the photosynthetic system. Further treatment of these fragments with Triton X-100 produces two additional fragments, a blue heavy (H) and an orange light (L) fragment, which are separable by sucrose density gradient centrifugation. Although both the physiological reactions related to photosynthesis (NADP+ photoreduction and O2 evolution) are missing from these derived particles, physical and biochemical evidence allows an identification of the two fragments. P700 is localized in the H fragment. Fluorescence spectra at room and liquid N2 temperature, as well as P700 response, show that the H fragment is related to Photosystem 1 and the L fragment is derived from Photosystem 2. On the basis of chlorophyll content the concentrations of carotenoids, lipid and protein are higher in the L fragment, while the ratio of β-carotene to total xanthophylls is higher in the H fragment. Of the total chlorophyll, a, 80% is found in the H fragment. The electron micrographs of these fragments show that the H fragment consists of flat discs 0.1-0.3 μ in diameter on which many small 100-Å particles are present, while the L fragment consists of small membrane fragments and irregular stranded material 50-60 Å in width. © 1960.