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Separation of Photosystems I and II from the oxychlorobacterium (prochlorophyte) Prochlorothrix hollandica and association of chlorophyll b binding antennae with Photosystem II

1992; Elsevier BV; Volume: 1102; Issue: 2 Linguagem: Inglês

10.1016/0005-2728(92)90103-9

1879-2650

Georg W.M. van der Staay, Annet Brouwer, Robert L. Baard, Frank van Mourik, Hans C. P. Matthijs,

Photoreceptor and optogenetics research

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.