IMMUNOLOGICALCROSSREACTIONSBETWEENP700CHLOROPHYLLPROTEINSISOLATEDFROMTWOMARINEGREENALGAEANDONEHIGHERPLANT

<正> P700 Chi-protein was isolated from a marine green alga Bryopsis corticulans with SDS-resolved thylakoid membranes by SDS-PAGE. After elution from the gel, the recovered protein revealed a 100 KD polypeptide by re-electrophoresis . The same SDS-PAGE procedure was used to isolate P700 Chl-proteins from spinach (Spinacea okracea ) and another marine green alga Codium fragile . Polyclonal antibodies to Bryopsis P700 protein were raised in rabbits. The antibodies were shown to cross-react with P700 Chl-protein and Chl-protein complexes containing P700 protein from B . Corticulans, C. f ragile, and even spinach. Results indicate similarity of the amino acid sequences of the P700 Chl-proteins and the highly conserved structure of the apoproteins of phylogenetically distant species over evolution. The antibodies cross-react with none of the components of PSUU in the species tested , indicating an independent pathway of evolution of photosystem I and photosystem II of later origin.