8hjv | pdb_00008hjv

Cryo-EM structure of carotenoid-depleted RC-LH complex from Roseiflexus castenholzii at 10,000 lux

spinqualitylabelsall models 8hjv, resolution 3.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8hjv is a 35 chain structure with sequence from Roseiflexus castenholzii DSM 13941. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.1Å Ligands: BPH, FE, HEM, KGD, MQE, PGV Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A7NQE9_ROSCS Antenna complexes are light-harvesting systems, which transfer the excitation energy to the reaction centers.[ARBA:ARBA00002455] Publication Abstract from PubMed Carotenoid (Car) pigments perform central roles in photosynthesis-related light harvesting (LH), photoprotection, and assembly of functional pigment-protein complexes. However, the relationships between Car depletion in the LH, assembly of the prokaryotic reaction center (RC)-LH complex, and quinone exchange are not fully understood. Here, we analyzed native RC-LH (nRC-LH) and Car-depleted RC-LH (dRC-LH) complexes in Roseiflexus castenholzii, a chlorosome-less filamentous anoxygenic phototroph that forms the deepest branch of photosynthetic bacteria. Newly identified exterior Cars functioned with the bacteriochlorophyll B800 to block the proposed quinone channel between LHalphabeta subunits in the nRC-LH, forming a sealed LH ring that was disrupted by transmembrane helices from cytochrome c and subunit X to allow quinone shuttling. dRC-LH lacked subunit X, leading to an exposed LH ring with a larger opening, which together accelerated the quinone exchange rate. We also assigned amino acid sequences of subunit X and two hypothetical proteins Y and Z that functioned in forming the quinone channel and stabilizing the RC-LH interactions. This study reveals the structural basis by which Cars assembly regulates the architecture and quinone exchange of bacterial RC-LH complexes. These findings mark an important step forward in understanding the evolution and diversity of prokaryotic photosynthetic apparatus. Carotenoid assembly regulates quinone diffusion and the Roseiflexus castenholzii reaction center-light harvesting complex architecture.,Xin J, Shi Y, Zhang X, Yuan X, Xin Y, He H, Shen J, Blankenship RE, Xu X Elife. 2023 Sep 22;12:e88951. doi: 10.7554/eLife.88951. PMID:37737710 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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