7r0w

2.8 Angstrom cryo-EM structure of the dimeric cytochrome b6f-PetP complex from Synechocystis sp. PCC 6803 with natively bound lipids and plastoquinone molecules

spinqualitylabelsall models 7r0w, resolution 2.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7r0w is a 18 chain structure with sequence from Synechocystis and Synechocystis sp. PCC 6803. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.8Å Ligands: 2WA, 6PL, CLA, ECH, FES, HEC, HEM, LFA, LMG, PGV, PL9, SQD Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function P72798_SYNY3 Publication Abstract from PubMed In oxygenic photosynthesis, the cytochrome b6f (cytb6f) complex links the linear electron transfer (LET) reactions occurring at photosystems I and II and generates a transmembrane proton gradient via the Q-cycle. In addition to this central role in LET, cytb6f also participates in a range of processes including cyclic electron transfer (CET), state transitions and photosynthetic control. Many of the regulatory roles of cytb6f are facilitated by auxiliary proteins that differ depending upon the species, yet because of their weak and transient nature the structural details of these interactions remain unknown. An apparent key player in the regulatory balance between LET and CET in cyanobacteria is PetP, a approximately 10 kDa protein that is also found in red algae but not in green algae and plants. Here, we used cryogenic electron microscopy to determine the structure of the Synechocystis sp. PCC 6803 cytb6f complex in the presence and absence of PetP. Our structures show that PetP interacts with the cytoplasmic side of cytb6f, displacing the C-terminus of the PetG subunit and shielding the C-terminus of cytochrome b6, which binds the heme cn cofactor that is suggested to mediate CET. The structures also highlight key differences in the mode of plastoquinone binding between cyanobacterial and plant cytb6f complexes, which we suggest may reflect the unique combination of photosynthetic and respiratory electron transfer in cyanobacterial thylakoid membranes. The structure of cytb6f from a model cyanobacterial species amenable to genetic engineering will enhance future site-directed mutagenesis studies of structure-function relationships in this crucial ET complex. Cryo-EM structures of the Synechocystis sp. PCC 6803 cytochrome b6f complex with and without the regulatory PetP subunit.,Proctor MS, Malone LA, Farmer DA, Swainsbury DJK, Hawkings FR, Pastorelli F, Emrich-Mills TZ, Siebert CA, Hunter CN, Johnson MP, Hitchcock A Biochem J. 2022 Jul 15;479(13):1487-1503. doi: 10.1042/BCJ20220124. PMID:35726684 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cytochrome b6

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