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6rqf

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Revision as of 00:23, 7 March 2020

3.6 Angstrom cryo-EM structure of the dimeric cytochrome b6f complex from Spinacia oleracea with natively bound thylakoid lipids and plastoquinone molecules

6rqf, resolution 3.58Å

Structural highlights

6rqf is a 16 chain structure with sequence from Spinacia oleracea. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:
Activity:	Plastoquinol--plastocyanin reductase, with EC number 7.1.1.6
Experimental data:	Check to display Experimental Data
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[PETM_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions. [CYF_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions. [PETG_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions. PetG is required for either the stability or assembly of the cytochrome b6-f complex.[HAMAP-Rule:MF_00432] [PETD_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions.[HAMAP-Rule:MF_01344] [PETN_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions. [CYB6_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions.[HAMAP-Rule:MF_00633] [UCRIA_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions (By similarity). [PETL_SPIOL] Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions. PetL is important for photoautotrophic growth as well as for electron transfer efficiency and stability of the cytochrome b6-f complex.[HAMAP-Rule:MF_00433]

Publication Abstract from PubMed

The cytochrome b6 f (cytb6 f ) complex has a central role in oxygenic photosynthesis, linking electron transfer between photosystems I and II and converting solar energy into a transmembrane proton gradient for ATP synthesis(1-3). Electron transfer within cytb6 f occurs via the quinol (Q) cycle, which catalyses the oxidation of plastoquinol (PQH2) and the reduction of both plastocyanin (PC) and plastoquinone (PQ) at two separate sites via electron bifurcation(2). In higher plants, cytb6 f also acts as a redox-sensing hub, pivotal to the regulation of light harvesting and cyclic electron transfer that protect against metabolic and environmental stresses(3). Here we present a 3.6 A resolution cryo-electron microscopy (cryo-EM) structure of the dimeric cytb6 f complex from spinach, which reveals the structural basis for operation of the Q cycle and its redox-sensing function. The complex contains up to three natively bound PQ molecules. The first, PQ1, is located in one cytb6 f monomer near the PQ oxidation site (Qp) adjacent to haem bp and chlorophyll a. Two conformations of the chlorophyll a phytyl tail were resolved, one that prevents access to the Qp site and another that permits it, supporting a gating function for the chlorophyll a involved in redox sensing. PQ2 straddles the intermonomer cavity, partially obstructing the PQ reduction site (Qn) on the PQ1 side and committing the electron transfer network to turnover at the occupied Qn site in the neighbouring monomer. A conformational switch involving the haem cn propionate promotes two-electron, two-proton reduction at the Qn site and avoids formation of the reactive intermediate semiquinone. The location of a tentatively assigned third PQ molecule is consistent with a transition between the Qp and Qn sites in opposite monomers during the Q cycle. The spinach cytb6 f structure therefore provides new insights into how the complex fulfils its catalytic and regulatory roles in photosynthesis.

Cryo-EM structure of the spinach cytochrome b6 f complex at 3.6 A resolution.,Malone LA, Qian P, Mayneord GE, Hitchcock A, Farmer DA, Thompson RF, Swainsbury DJK, Ranson NA, Hunter CN, Johnson MP Nature. 2019 Nov;575(7783):535-539. doi: 10.1038/s41586-019-1746-6. Epub 2019 Nov, 13. PMID:31723268^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Malone LA, Qian P, Mayneord GE, Hitchcock A, Farmer DA, Thompson RF, Swainsbury DJK, Ranson NA, Hunter CN, Johnson MP. Cryo-EM structure of the spinach cytochrome b6 f complex at 3.6 A resolution. Nature. 2019 Nov;575(7783):535-539. doi: 10.1038/s41586-019-1746-6. Epub 2019 Nov, 13. PMID:31723268 doi:http://dx.doi.org/10.1038/s41586-019-1746-6

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/6rqf"

@@ Line 1: / Line 1: @@
 ==3.6 Angstrom cryo-EM structure of the dimeric cytochrome b6f complex from Spinacia oleracea with natively bound thylakoid lipids and plastoquinone molecules==
-<StructureSection load='6rqf' size='340' side='right'caption='[[6rqf]], [[Resolution|resolution]] 3.58&Aring;' scene=''>
+<SX load='6rqf' size='340' side='right' viewer='molstar' caption='[[6rqf]], [[Resolution|resolution]] 3.58&Aring;' scene=''>
 == Structural highlights ==
 <table><tr><td colspan='2'>[[6rqf]] is a 16 chain structure with sequence from [http://en.wikipedia.org/wiki/Spinacia_oleracea Spinacia oleracea]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6RQF OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6RQF FirstGlance]. <br>
@@ Line 22: / Line 22: @@
 <references/>
 __TOC__
-</StructureSection>
+</SX>
 [[Category: Large Structures]]
 [[Category: Plastoquinol--plastocyanin reductase]]

6rqf

From Proteopedia

Revision as of 00:23, 7 March 2020

3.6 Angstrom cryo-EM structure of the dimeric cytochrome b6f complex from Spinacia oleracea with natively bound thylakoid lipids and plastoquinone molecules

Structural highlights

Function

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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