Structural highlights
6et5 is a 54 chain structure with sequence from Blastochloris viridis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
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| Ligands: | , , , , , , , , , |
| NonStd Res: | |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[LHB_BLAVI] Antenna complexes are light-harvesting systems, which transfer the excitation energy to the reaction centers. [RCEH_BLAVI] The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. [CYCR_BLAVI] The reaction center of purple bacteria contains a tightly bound cytochrome molecule which re-reduces the photo oxidized primary electron donor.[1] [RCEM_BLAVI] The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. [LHG_BLAVI] One of the components of the bacteriochlorophyll-protein complex in the chromatophore membrane. [RCEL_BLAVI] The reaction center is a membrane-bound complex that mediates the initial photochemical event in the electron transfer process of photosynthesis. [LHA_BLAVI] Antenna complexes are light-harvesting systems, which transfer the excitation energy to the reaction centers.
Publication Abstract from PubMed
The light-harvesting 1-reaction centre (LH1-RC) complex is a key functional component of bacterial photosynthesis. Here we present a 2.9 A resolution cryo-electron microscopy structure of the bacteriochlorophyll b-based LH1-RC complex from Blastochloris viridis that reveals the structural basis for absorption of infrared light and the molecular mechanism of quinone migration across the LH1 complex. The triple-ring LH1 complex comprises a circular array of 17 beta-polypeptides sandwiched between 17 alpha- and 16 gamma-polypeptides. Tight packing of the gamma-apoproteins between beta-polypeptides collectively interlocks and stabilizes the LH1 structure; this, together with the short Mg-Mg distances of bacteriochlorophyll b pairs, contributes to the large redshift of bacteriochlorophyll b absorption. The 'missing' 17th gamma-polypeptide creates a pore in the LH1 ring, and an adjacent binding pocket provides a folding template for a quinone, Q P, which adopts a compact, export-ready conformation before passage through the pore and eventual diffusion to the cytochrome bc 1 complex.
Cryo-EM structure of the Blastochloris viridis LH1-RC complex at 2.9 A.,Qian P, Siebert CA, Wang P, Canniffe DP, Hunter CN Nature. 2018 Apr;556(7700):203-208. doi: 10.1038/s41586-018-0014-5. Epub 2018 Apr, 4. PMID:29618818[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Chen IP, Mathis P, Koepke J, Michel H. Uphill electron transfer in the tetraheme cytochrome subunit of the Rhodopseudomonas viridis photosynthetic reaction center: evidence from site-directed mutagenesis. Biochemistry. 2000 Apr 4;39(13):3592-602. PMID:10736158
- ↑ Qian P, Siebert CA, Wang P, Canniffe DP, Hunter CN. Cryo-EM structure of the Blastochloris viridis LH1-RC complex at 2.9 A. Nature. 2018 Apr;556(7700):203-208. doi: 10.1038/s41586-018-0014-5. Epub 2018 Apr, 4. PMID:29618818 doi:http://dx.doi.org/10.1038/s41586-018-0014-5
