Structural highlights
FunctionSDHA_YEAST Catalytic subunit of succinate dehydrogenase (SDH) that is involved in complex II of the mitochondrial electron transport chain and is responsible for transferring electrons from succinate to ubiquinone (coenzyme Q). SDH1 and SDH2 form the catalytic dimer. Electrons flow from succinate to the FAD bound to SDH1, and sequentially through the iron-sulfur clusters bound to SDH2 and enter the membrane dimer formed by SDH3 and SDH4. Publication Abstract from PubMedRespiratory complex II (CII), or succinate dehydrogenase, couples succinate oxidation in the Krebs cycle with electron transfer to the respiratory chain. Owing to this pivotal role, CII inhibitors are widely used fungicides globally; however, their development has largely proceeded without structural insights from fungal targets. Here, we report cryo-electron microscopy structures of the 128 kDa mitochondrial CII from Saccharomyces cerevisiae in two states: active, with endogenous ubiquinone-6 bound (3.15 A), and inhibited with the fungicide bixafen (3.00 A). Although closely related to the mammalian type C enzyme, our structures show that the yeast CII has lost the canonical heme cofactor. They also reveal how clade-specific sequence extensions of the membrane subunits Sdh3 and Sdh4 - conserved in pathogenic fungi - uniquely contribute to complex stability and fungicide binding. Our findings provide a foundation for rational design of next-generation CII inhibitors and combatting resistance, in both agriculture and human health. Cryo-EM structure of bixafen-bound S. cerevisiae complex II unravels SDHI specificity against pathogenic fungi.,Pinotsis N, Burn-Leefe C, Jones S, Chen S, Lukoyanova N, Meunier B, Berry EA, Marechal A Commun Biol. 2026 Jan 28. doi: 10.1038/s42003-026-09617-8. PMID:41606097[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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