Abstract
The light-harvesting chlorophyll a/b complex (LHCP II) of Euglena gracilis contains a 26.5- kDa polypeptide. This polypeptide is low or undetectable in wild-type cells grown in darkness or in dark-grown resting wild-type cells exposed to 7 ft-c of light (the threshold for chloroplast development). On exposure of dark-grown resting cells or cells at 7 ft-c to a normal intensity for development (80 ft-c), the 26.5-kDa apoprotein is rapidly formed. Using a highly specific antibody to the 26.5-kDa apoprotein, little reaction can be detected in electron micrographs of dark-grown resting cells or the same cells at 7 ft-c, as determined by deposition of protein A-gold. However, in the same cells after exposure to 80 ft-c of light, gold deposition over the Golgi apparatus as well as the thylakoids of the plastids can be seen. No deposition is seen if preimmune serum is substituted for immune serum.
