An electron transfer path connects subunits of a mycobacterial respiratory supercomplex
Hongri GongJun LiAo XuYanting TangWenxin JiRuogu GaoShuhui WangLu YuChanglin TianJingwen LiHsin‐Yung YenSin Man LamGuanghou ShuiXiuna YangYuna SunXuemei LiMinze JiaCheng YangBiao JiangZhiyong LouCarol V. RobinsonLuet‐Lok WongLuke W. GuddatFei SunQuan WangZihe Rao
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Abstract:
An electron bridge in place of a ferry Respiratory complexes are massive, membrane-embedded scaffolds that position redox cofactors so as to permit electron transfer coupled to the movement of protons across a membrane. Gong et al. used cryo–electron microscopy to determine a structure of a stable assembly of mycobacterial complex III–IV, in which a complex III dimer is sandwiched between two complex IV monomers. A potential direct electron transfer path stretches from the quinone oxidizing centers in complex III to the oxygen reduction centers in complex IV. A loosely associated superoxide dismutase may play a role in detoxifying superoxide produced from uncoupled oxygen reduction. Science , this issue p. eaat8923Keywords:
Mycobacterium smegmatis
The textbook description of mitochondrial respiratory complexes (RCs) views them as free-moving entities linked by the mobile carriers coenzyme Q (CoQ) and cytochrome c (cyt c). This model (known as the fluid model) is challenged by the proposal that all RCs except complex II can associate in supercomplexes (SCs). The proposed SCs are the respirasome (complexes I, III, and IV), complexes I and III, and complexes III and IV. The role of SCs is unclear, and their existence is debated. By genetic modulation of interactions between complexes I and III and III and IV, we show that these associations define dedicated CoQ and cyt c pools and that SC assembly is dynamic and organizes electron flux to optimize the use of available substrates.
Mitochondrial respiratory chain
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