Light-harvesting role

In this chapter we shall summarize the structure of the LH2 (B800-850) antenna complex from the purple non-sulfur photosynthetic bacterium Rhodopseudomonas acidophila strain 10050, placing special emphasis on the carotenoids. We will then review what is currently known about the details of the carotenoid s light-harvesting role in this system. 

Although all chlorophyll-protein complexes isolated to date, whether they are associated with PS I or II, contain carotenoids, it is only in two classes of complexes that carotenoids play the major light-harvesting role. These two classes are the unique... 

Detergent treatment of a suspension of thylakoids dissolves the membranes, releasing complexes containing both chlorophyll and protein. These chlorophyll-protein complexes represent integral components of the thylakoid membrane, and their organization reflects their roles as either light-harvesting com-... 

Horton P., Ruban, A.V., Rees D., A. Pascal, Noctor, G.D., and Young, A.J. 1991. Control of the light-harvesting function of chloroplast membranes by the proton concentration in the thylakoid lumen aggregation states of the LHCII complex and the role of zeaxanthin. FEBS Lett. 292 1-4. 

Horton, P. and Ruban, A.V. 1994. The role of light-harvesting complex II in energy quenching. In Photoinhibition of Photosynthesis, eds. N.R. Baker and J.R. Bowyer, pp. 11-128. Oxford BIOS Scientific Publishers Ltd. 

Koyama, Y., F. S. Rondonuwu, R. Fujii, and Y. Watanabe. 2004. Light-harvesting function of carotenoids in photosynthesis The roles of the newly found 1B state. Biopolymers 74 2-18. 

Carotenoids exhibit multiple physiological roles, i.e. as light-harvesting pigments in photosynthesis, as quenching solutes for the triplet state of chlorophyll a to... 

Nonradiative energy transfer has a major role in the process of photosynthesis. Light is absorbed by large numbers of chlorophyll molecules in light-harvesting antennae and energy is transferred in a stepwise manner to photosynthetic reaction centres, at which photochemical reactions occur. This fundamental energy-transfer process will be considered in more detail in Chapter 12. 

Finally, carotenoids are the metabolic precursors for three more of the flavor volatiles of the tomato. Although the role of carotenoids, light-harvesting pigments in plants, in human nutrition is the subject of debate, these compounds are antioxidants and P-carotene is the principal source of the visual pigments of the eye. 

I.J. Ryrie and N. Fuad, Membrane adhesion in reconstituted proteoliposomes containing the light-harvesting chlorophyll a/b-protein complex the role of charged surface groups, Arch. Biochem. Biophys. 214 (1982) 475-488. 

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