Identification of chloroplast coupling factor by freeze-etching and negative-staining techniques.
Identification of chloroplast coupling factor particles, by the freeze-etching and negative-staining techniques, was made utilizing chloroplast thylakoids isolated from spinach leaves. Complete removal of particles, comparable in diameter to purified coupling factor particles, from the outer surface of freeze-etched thylakoids was achieved by treatment with 0.8% silicotungstate. Reappearance of particles, comparable in diameter to purified coupling factor particles, on the outer surface of freeze-etched thylakoids was demonstrated by combining silicotungstate-treated thylakoids with purified chloroplast coupling factor. Negative-staining results were in agreement with the freeze-etch data. The results demonstrate that the chloroplast coupling factor particles are exposed on the outer surface.
D002736:Chloroplasts / Q000648:ultrastructure*; D005613:Freeze Etching; D008854:Microscopy, Electron; D008954:Models, Biological; D010772:Phosphotungstic Acid; D010944:Plants / Q000648:ultrastructure; D013194:Staining and Labeling
D010772:Phosphotungstic Acid