Studies of chloroplast thylakoid proteins using monoclonal antibodies.

Several monoclonal antibodies have been produced against partially purified photosystem I reaction center complexes isolated from spinach chloroplasts. One of the clones was shown to be highly specific for the 28,000 and 27,000 dalton subunits of purified light harvesting chlorophyll a/b binding complex. Studies with thylakoids suggest at least a portion of the light harvesting chlorophyll a/b binding protein molecules are exposed on a normally inaccessible surface of the membrane.