SEPARATION OF PHOTOSYSTEM-I AND PHOTOSYSTEM-II FROM THE OXYCHLOROBACTERIUM (PROCHLOROPHYTE) PROCHLOROTHRIX-HOLLANDICA AND ASSOCIATION OF CHLOROPHYLL-B BINDING ANTENNAE WITH PHOTOSYSTEM-II

Photosystem I and Photosystem II plus associated chlorophyll a/b-protein complexes were isolated from washed thylakoid membranes of the oxychlorobacterium (prochlorophyte) Prochlorothrix hollandica. Separation was achieved by solubilization with Zwittergent 14 and sucrose gradient centrifugation. Characterization involved non-denaturing and SDS-gel electrophoresis, immunodecoration, pigment content estimation by HPLC and analysis by absorbance and fluorescence spectroscopy. The data obtained indicate a functional positioning of the chlorophyll a/b antennae in the vicinity of Photosystem II. Fractions enriched in these antennae contain at least four polypeptides, of 28 to 30, 32, 34 and 36 kDa. The chlorophyll a to b ratio of the separated antennae was estimated to be about 4. As opposed to higher plant and green algal chloroplasts, Photosystem I of Prochlorothrix does not appear to have its own separate chlorophyll b containing antenna.