Assembly of Light Harvesting Pigment-Protein Complexes in Photosynthetic Eukaryotes

摘要: In photosynthetic eukaryotes, the antenna system includes members of a protein family Light-harvesting complexes encoded by Lhc genes. These proteins bind 8–14 chlorophylls (Chls) and 2–4 carotenoid molecules per 22–28 kDa polypeptide; further, pigments are needed for assembly monomeric proteins. Some form dimers (LHCI) or trimers (LHCII). Chl is all proteins, while two members, Lhca1 Lhca3, can refold in vitro without b. Among carotenoids, lutein bound to site L1 whose occupancy essential assembly. Violaxanthin zeaxanthin also drive folding, although with lower efficiency respect lutein. Current knowledge on mechanisms reviewed this chapter: experiments have shown how folding triggered binding lutein; contrast b only second phase functions stabilize pigment-protein complexes. Together reaction centers, organized as supercomplexes thylakoid membranes. The structural organization Photosystem I (PS I) quite different from that II II): PS flexible its size modulated according environmental conditions, content maintained constant center.