Structural highlights
Function[D2Z0P1_THETI] Antenna complexes are light-harvesting systems, which transfer the excitation energy to the reaction centers (By similarity).[SAAS:SAAS000066_004_008786] [D2Z0P5_THETI] The reaction center of purple bacteria contains a tightly bound cytochrome molecule which re-reduces the photo oxidized primary electron donor (By similarity).[PIRNR:PIRNR000017] [D2Z0P2_THETI] Antenna complexes are light-harvesting systems, which transfer the excitation energy to the reaction centers (By similarity).[SAAS:SAAS000066_004_008786] Publication Abstract from PubMedThe light-harvesting core antenna (LH1) and the reaction centre (RC) of purple photosynthetic bacteria form a supramolecular complex (LH1-RC) to use sunlight energy in a highly efficient manner. Here we report the first near-atomic structure, to our knowledge, of a LH1-RC complex, namely that of a Ca2+-bound complex from Thermochromatium tepidum, which reveals detailed information on the arrangement and interactions of the protein subunits and the cofactors. The RC is surrounded by 16 heterodimers of the LH1 alphabeta-subunit that form a completely closed structure. The Ca2+ ions are located at the periplasmic side of LH1. Thirty-two bacteriochlorophyll and 16 spirilloxanthin molecules in the LH1 ring form an elliptical assembly. The geometries of the pigment assembly involved in the absorption characteristics of the bacteriochlorophyll in LH1 and excitation energy transfer among the pigments are reported. In addition, possible ubiquinone channels in the closed LH1 complex are proposed based on the atomic structure. Structure of the LH1-RC complex from Thermochromatium tepidum at 3.0 A,Niwa S, Yu LJ, Takeda K, Hirano Y, Kawakami T, Wang-Otomo ZY, Miki K Nature. 2014 Mar 26. doi: 10.1038/nature13197. PMID:24670637[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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