Organization and regulation of the photosynthetic membrane

Photosystem I of higher plants consist of a core and a peripheral antenna. The core consist of 14 different protein subunits which binds all the components of the electron transfer chain and also contain approximately 100 chlorophyll molecules which serve as antenna capturing light. The peripheral antennae consist of at least 4 different proteins belonging to the chlorophyll a/b-binding protein family.

Schematic model of PSI side-view

 

Most of the genes encoding subunits of PSI can be suppressed or knocked-out without lethal effects on the plants. Using transgenic plants with reduced levels of specific PSI subunits, the significance and function of these subunits are studied at the whole plant level under different growth conditions.

 

Photosystem II possesses the unique ability to use solar radiation to split water and use the electrons from water in electron transport eventually resulting in the fixation of CO₂ and plant growth (food, feed and biomass).

 

Both PS I and PS II are directly dependent on metal ions such as manganese, iron and cupper for proper function. These micronutrients are therefore essential for plants and it is of interest to investigate how a deficiency in one of these is reflected in the function and composition of the photosynthetic complexes.

 

Schematic model of PSI top view