Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Cryo-EM structure of HQNO-bound Alternative Complex III from the anoxygenic phototrophic bacterium Chloroflexus aurantiacus.
Journal, issue, pages	Plant Cell, Year 2024
Publish date	Jan 31, 2024
Authors	Jiyu Xin / Zhenzhen Min / Lu Yu / Xinyi Yuan / Aokun Liu / Wenping Wu / Xin Zhang / Huimin He / Jingyi Wu / Yueyong Xin / Robert E Blankenship / Changlin Tian / Xiaoling Xu /
PubMed Abstract	Alternative complex III (ACIII) couples quinol oxidation and electron acceptor reduction with potential transmembrane proton translocation. It is compositionally and structurally different from the ...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 (HQNO). Besides six canonical subunits (ActABCDEF), the structures revealed conformations of two 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 (EPR), spectroelectrochemistry, enzymatic analyses and molecular dynamics (MD) 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.
External links	Plant Cell / PubMed:38299372
Methods	EM (single particle)
Resolution	2.7 - 3.33 Å
Structure data	36984 8k9e EMDB-36984, PDB-8k9e: Cryo-EM structure of the photosynthetic alternative complex III from Chloroflexus aurantiacus at 3.3 angstrom Method: EM (single particle) / Resolution: 3.33 Å 36985 8k9f EMDB-36985, PDB-8k9f: Cryo-EM structure of the photosynthetic alternative complex III from Chloroflexus aurantiacus at 2.9 angstrom Method: EM (single particle) / Resolution: 2.9 Å 38012 8x2j EMDB-38012, PDB-8x2j: Cryo-EM structure of the photosynthetic alternative complex III with a quinone inhibitor HQNO from Chloroflexus aurantiacus Method: EM (single particle) / Resolution: 2.7 Å
Chemicals	ChemComp-HEC: HEME C / Heme C ChemComp-SF4: IRON/SULFUR CLUSTER / Iron–sulfur cluster ChemComp-F3S: FE3-S4 CLUSTER / Iron–sulfur cluster ChemComp-EL6: [(2S)-2-octadecanoyloxypropyl] octadecanoate ChemComp, No image ChemComp-JLQ: Unknown entry ChemComp, No image ChemComp-JL3: Unknown entry ChemComp, No image ChemComp-JM9: Unknown entry ChemComp-MG: Unknown entry ChemComp-HQO: 2-HEPTYL-4-HYDROXY QUINOLINE N-OXIDE
Source	chloroflexus aurantiacus (strain atcc 29366 / dsm 635 / j-10-fl) (bacteria)
Keywords	MEMBRANE PROTEIN / Photosynthetic alternative complex III