Immunological evidence for apoproteins of the light-harvesting chlorophyll-protein complex in a mutant of barley lacking chlorophyll b.

A barley mutant lacking chlorophyll b and the pigmented light-harvesting chlorophyll-protein of photo-system 2 is shown by several criteria to contain functional apoproteins of the light-harvesting complex. 1. Electrophoretic comparison of thylakoid polypeptide patterns, and the effects of trypsin treatment on these, suggests that the mutant contains several polypeptides equivalent in mobility to those of the wild-type complex. 2. An antibody monospecific for the light-harvesting complex agglutinated both wild-type and mutant thylakoids. 3. 'Western blot' immunoelectrophoretic analysis indicated that of four distinct subunits of the light-harvesting complex in the wild-type thylakoids, three are detectable in the mutant. 4. As in wild-type lamellae at least one of the light-harvesting complex polypeptides is phosphorylated by the endogenous protein kinase. The results are considered in terms of a general role for the light-harvesting complex polypeptides in membrane appression and the regulation of excitation energy distribution within thylakoids.