8k9e: Difference between revisions
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<table><tr><td colspan='2'>[[8k9e]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Chloroflexus_aurantiacus_J-10-fl Chloroflexus aurantiacus J-10-fl]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8K9E OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8K9E FirstGlance]. <br> | <table><tr><td colspan='2'>[[8k9e]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Chloroflexus_aurantiacus_J-10-fl Chloroflexus aurantiacus J-10-fl]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8K9E OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8K9E FirstGlance]. <br> | ||
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.33Å</td></tr> | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.33Å</td></tr> | ||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EL6:[( | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=EL6:[(2~{S})-2-octadecanoyloxypropyl]+octadecanoate'>EL6</scene>, <scene name='pdbligand=HEC:HEME+C'>HEC</scene>, <scene name='pdbligand=JL3:[(2~{R})-3-[2-azanylethoxy(oxidanyl)phosphoryl]oxy-2-pentadecanoyloxy-propyl]+pentadecanoate'>JL3</scene>, <scene name='pdbligand=JLQ:[(2~{R})-3-[2-azanylethoxy(oxidanyl)phosphoryl]oxy-2-tetradecanoyloxy-propyl]+hexadecanoate'>JLQ</scene>, <scene name='pdbligand=JM9:1,3-bis(13-methyltetradecanoyloxy)propan-2-yl+pentadecanoate'>JM9</scene></td></tr> | ||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8k9e FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8k9e OCA], [https://pdbe.org/8k9e PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8k9e RCSB], [https://www.ebi.ac.uk/pdbsum/8k9e PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8k9e ProSAT]</span></td></tr> | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8k9e FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8k9e OCA], [https://pdbe.org/8k9e PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8k9e RCSB], [https://www.ebi.ac.uk/pdbsum/8k9e PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8k9e ProSAT]</span></td></tr> | ||
</table> | </table> | ||
== Function == | == Function == | ||
[https://www.uniprot.org/uniprot/A9WEV2_CHLAA A9WEV2_CHLAA] | [https://www.uniprot.org/uniprot/A9WEV2_CHLAA A9WEV2_CHLAA] | ||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Alternative complex III (ACIII) couples quinol oxidation and electron acceptor reduction with potential transmembrane proton translocation. It is compositionally and structurally different from the cytochrome bc1/b6f complexes but functionally replaces these enzymes in the photosynthetic and/or respiratory electron transport chains (ETCs) of many bacteria. However, the true compositions and architectures of ACIIIs remain unclear, as do their structural and functional relevance in mediating the ETCs. We here determined cryogenic electron microscopy structures of photosynthetic ACIII isolated from Chloroflexus aurantiacus (CaACIIIp), in apo-form and in complexed form bound to a menadiol analog 2-heptyl-4-hydroxyquinoline-N-oxide. Besides 6 canonical subunits (ActABCDEF), the structures revealed conformations of 2 previously unresolved subunits, ActG and I, which contributed to the complex stability. We also elucidated the structural basis of menaquinol oxidation and subsequent electron transfer along the [3Fe-4S]-6 hemes wire to its periplasmic electron acceptors, using electron paramagnetic resonance, spectroelectrochemistry, enzymatic analyses, and molecular dynamics simulations. A unique insertion loop in ActE was shown to function in determining the binding specificity of CaACIIIp for downstream electron acceptors. This study broadens our understanding of the structural diversity and molecular evolution of ACIIIs, enabling further investigation of the (mena)quinol oxidoreductases-evolved coupling mechanism in bacterial energy conservation. | |||
Cryo-EM structure of HQNO-bound alternative complex III from the anoxygenic phototrophic bacterium Chloroflexus aurantiacus.,Xin J, Min Z, Yu L, Yuan X, Liu A, Wu W, Zhang X, He H, Wu J, Xin Y, Blankenship RE, Tian C, Xu X Plant Cell. 2024 Oct 3;36(10):4212-4233. doi: 10.1093/plcell/koae029. PMID:38299372<ref>PMID:38299372</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 8k9e" style="background-color:#fffaf0;"></div> | |||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
Latest revision as of 11:29, 5 March 2025
Cryo-EM structure of the photosynthetic alternative complex III from Chloroflexus aurantiacus at 3.3 angstromCryo-EM structure of the photosynthetic alternative complex III from Chloroflexus aurantiacus at 3.3 angstrom
Structural highlights
FunctionPublication Abstract from PubMedAlternative complex III (ACIII) couples quinol oxidation and electron acceptor reduction with potential transmembrane proton translocation. It is compositionally and structurally different from the cytochrome bc1/b6f complexes but functionally replaces these enzymes in the photosynthetic and/or respiratory electron transport chains (ETCs) of many bacteria. However, the true compositions and architectures of ACIIIs remain unclear, as do their structural and functional relevance in mediating the ETCs. We here determined cryogenic electron microscopy structures of photosynthetic ACIII isolated from Chloroflexus aurantiacus (CaACIIIp), in apo-form and in complexed form bound to a menadiol analog 2-heptyl-4-hydroxyquinoline-N-oxide. Besides 6 canonical subunits (ActABCDEF), the structures revealed conformations of 2 previously unresolved subunits, ActG and I, which contributed to the complex stability. We also elucidated the structural basis of menaquinol oxidation and subsequent electron transfer along the [3Fe-4S]-6 hemes wire to its periplasmic electron acceptors, using electron paramagnetic resonance, spectroelectrochemistry, enzymatic analyses, and molecular dynamics simulations. A unique insertion loop in ActE was shown to function in determining the binding specificity of CaACIIIp for downstream electron acceptors. This study broadens our understanding of the structural diversity and molecular evolution of ACIIIs, enabling further investigation of the (mena)quinol oxidoreductases-evolved coupling mechanism in bacterial energy conservation. Cryo-EM structure of HQNO-bound alternative complex III from the anoxygenic phototrophic bacterium Chloroflexus aurantiacus.,Xin J, Min Z, Yu L, Yuan X, Liu A, Wu W, Zhang X, He H, Wu J, Xin Y, Blankenship RE, Tian C, Xu X Plant Cell. 2024 Oct 3;36(10):4212-4233. doi: 10.1093/plcell/koae029. PMID:38299372[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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