To probe the location of the carboxyl-terminus of the 28 kDa apoprotein of the light-harvesting chlorophyll a/b-protein complex of PS II (LHCII), an antibody was generated against a synthetic octapeptide corresponding to the C-terminal region of LHCII. The high specificity of the octapeptide antiserum was deonstrated by immunoblots and immunogold labelling. The octapeptide antiserum agglutinated destacked thylakoid membranes, but no significant agglutination occurred with inside-out vesicles suggesting that the COOH-terminus is located at the outer, stroma-exposed surface where the NH2-terminus is also located [(1983) J. Biol. Chem. 258, 9941-9948]. Our results support a model for LHCII with four transmembrane-spanning domains.
