Glycolipids and thylakoid proteins in chloroplasts and streptomycin-bleached lamellae ofEuglena

Thylakoid proteins from (a) the chloroplasts of greenEuglena gracilis cells and from (b) the corresponding concentric lamellar bodies of streptomycin-bleachedEuglena have been extracted in aqueous sodium dodecyl sulfate (SDS) and purified. The molecular weights of the proteins, determined by polyacrylamide gel electrophoresis in SDS, were 9 kilodaltons for (a) and 9 and 11.5 kilodaltons for the 2 polypeptide chains of (b). Each of the purified proteins consists of 55% apolar and 45% polar amino acids. The lipids of the green and bleached cells differ in polarity of components. Neutral galactolipids are abundant in green cells but not in streptomycin-bleached cells. Anionic sulfolipid content is greater in the chlorotic organisms. Polyenoic fatty acids, mainly with 16, 18 and 19 carbon atoms, occur in the green cell galactolipids. Cells grown in the presence of streptomycin are, in contrast, rich in monoenes. The opposite is observed in the sulfolipids: monoenes with 16 and 20 carbons are the main fatty acids in the green cells, while a dienoic fatty acid with 12 carbons is found in large amounts in streptomycin-bleached cultures.