Abstract
Land plants use two chlorophyll molecules, chlorophyll a and b, for photosynthesis. While both two chlorophylls work together in light harvesting antenna, only chlorophyll a is used in the photochemical reaction center. Previous studies showed that chlorophyll b-less mutants can survive under normal growth conditions, although they are susceptible to photo-oxidative damage by high light illumination. However, the detailed structure of photosynthetic apparatus in chlorophyll b-less plants remains unknown.
In this study, we analyzed the thylakoid proteins of chlorophyll b-excess and -less mutants by both BN-PAGE and the proteomic approaches.
BN-PAGE showed that neither PSII supercomplexes nor LHCII trimers were not formed in the chlorophyll b-less mutant, and the size of the PS I complex was greatly decreased. Two dimentional SDS gel electrophoresis further suggested that chlorophyll b was essential for integration of light harvesting proteins into PS I and PS II core complexes.
Further proteomic analysis showed that the complete loss of chlorophyll b caused the dynamic changes of thylakoid protein compositions.
