EMD-6828
Cryo-EM structure of the RC-LH core complex from Roseiflexus castenholzii
EMD-6828
Single-particle4.1 Å
Deposition: 27/09/2017Map released: 02/05/2018
Last modified: 02/05/2018
Sample Organism:
Roseiflexus castenholzii
Sample: photosynthetic core complex
Fitted models: 5yq7 (Avg. Q-score: 0.402)
Deposition Authors: Xin YY, Shi Y, Niu TX, Wang QQ, Niu WQ, Huang XJ, Ding W, Blankenship RE, Xu XL, Sun F
Sample: photosynthetic core complex
Fitted models: 5yq7 (Avg. Q-score: 0.402)
Deposition Authors: Xin YY, Shi Y, Niu TX, Wang QQ, Niu WQ, Huang XJ, Ding W, Blankenship RE, Xu XL, Sun F
Cryo-EM structure of the RC-LH core complex from an early branching photosynthetic prokaryote.
Xin YY 
,
Shi Y ,
Niu TX,
Wang QQ,
Niu WQ,
Huang XJ,
Ding W ,
Yang L,
Blankenship RE ,
Xu XL ,
Sun F
(2018) Nat Commun , 9 , 1568 - 1568
,
Shi Y ,
Niu TX,
Wang QQ,
Niu WQ,
Huang XJ,
Ding W ,
Yang L,
Blankenship RE ,
Xu XL ,
Sun F
(2018) Nat Commun , 9 , 1568 - 1568
Abstract:
Photosynthetic prokaryotes evolved diverse light-harvesting (LH) antennas to absorb sunlight and transfer energy to reaction centers (RC). The filamentous anoxygenic phototrophs (FAPs) are important early branching photosynthetic bacteria in understanding the origin and evolution of photosynthesis. How their photosynthetic machinery assembles for efficient energy transfer is yet to be elucidated. Here, we report the 4.1 Å structure of photosynthetic core complex from Roseiflexus castenholzii by cryo-electron microscopy. The RC-LH complex has a tetra-heme cytochrome c bound RC encompassed by an elliptical LH ring that is assembled from 15 LHαβ subunits. An N-terminal transmembrane helix of cytochrome c inserts into the LH ring, not only yielding a tightly bound cytochrome c for rapid electron transfer, but also opening a slit in the LH ring, which is further flanked by a transmembrane helix from a newly discovered subunit X. These structural features suggest an unusual quinone exchange model of prokaryotic photosynthetic machinery.
Photosynthetic prokaryotes evolved diverse light-harvesting (LH) antennas to absorb sunlight and transfer energy to reaction centers (RC). The filamentous anoxygenic phototrophs (FAPs) are important early branching photosynthetic bacteria in understanding the origin and evolution of photosynthesis. How their photosynthetic machinery assembles for efficient energy transfer is yet to be elucidated. Here, we report the 4.1 Å structure of photosynthetic core complex from Roseiflexus castenholzii by cryo-electron microscopy. The RC-LH complex has a tetra-heme cytochrome c bound RC encompassed by an elliptical LH ring that is assembled from 15 LHαβ subunits. An N-terminal transmembrane helix of cytochrome c inserts into the LH ring, not only yielding a tightly bound cytochrome c for rapid electron transfer, but also opening a slit in the LH ring, which is further flanked by a transmembrane helix from a newly discovered subunit X. These structural features suggest an unusual quinone exchange model of prokaryotic photosynthetic machinery.