SLOW TURNOVER OF THE D1 REACTION-CENTER PROTEIN OF PHOTOSYSTEM-II IN LEAVES OF HIGH-MOUNTAIN PLANTS

The D1 reaction center protein of photosystem II usually exhibits a ra pid turnover in light, The D1 protein turnover was compared in three s pecies of alpine plants, Homogyne alpina, Ranunculus glacialis, Soldan ella alpina, and in the lowland plant Taraxacum officinale by radioact ive labeling in light and subsequent chase experiments, The DT protein of alpine plants could also be recognized by its more rapid labeling, relative to other membrane proteins, However, compared to T., officin ale the turnover er of the D1 protein was considerably slower in the a lpine plants, The potential advantage of a slow D1 turnover for adapta tion to the environmental conditions of high mountain plants is discus sed. (C) 1998 Federation of European Biochemical Societies.