Photosynthetic light-harvesting complex-reaction center complex (LH-RC complex)

The photosynthetic light-harvesting (LH) complexes and reaction center (RC) in anoxygenic photosynthetic bacteria are integral membrane protein-pigment assemblies that mediate the conversion of light into chemical energy [1]. These systems, primarily found in organisms like Rhodobacter sphaeroides, consist of peripheral LH2 and core LH1 complexes that funnel excitation energy to a central RC containing specific bacteriochlorophyll-binding sites [2]. Within the RC, light-induced electron transfer occurs across the membrane, creating an electrochemical gradient used for ATP production [1]. Although these complexes are not therapeutic targets for human disease, they serve as critical structural models for studying electron transfer and are the primary targets for certain classes of herbicides, such as triazines and uracils, which inhibit the RC by displacing ubiquinone at the QB binding site [3]. From a biotechnological perspective, these complexes are explored for their potential in bio-photovoltaics and as scaffolds for synthetic light-harvesting systems [2].

Other names

LH1-RC complexLH2 complexReaction centerBacteriochlorophyll-binding proteinsPhotosynthetic unit (PSU)P870 reaction center

Competitive inhibition of the secondary quinone (QB) binding site in the reaction center, preventing electron transfer from the primary quinone (QA).