Changes of the Polypeptide Composition in Thylakoid Membranes during Differentiation

Changes in membrane polypeptide composition during greening o f etiolated maize were in­ vestigated to confirm the existence o f the developmental polypeptides o f 12 15 kDa described recently in virescent soybean mutant [M. Droppa, M. L. Ghirardi, G. Horvath, and A. Melis, Biochim. Biophys. Acta 932, 138— 145 (1988)]. These low molecular weight polypeptides were the most abundant proteins at the early stage o f greening, but were largely absent from fully developed thylakoids. During greening the relative concentration o f the 12-15 kDa polypep­ tides were inversely proportional to that o f LHC II, suggesting a role o f these polypeptides in the assembly o f the LHC II and/or chloroplast development.