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Publication Abstract from PubMed

Tetrahymena thermophila, a classic ciliate model organism, has been shown to possess tubular mitochondrial cristae and highly divergent electron transport chain involving four transmembrane protein complexes (I-IV). Here we report cryo-EM structures of its ~8 MDa megacomplex IV(2 )+ (I + III(2 )+ II)(2), as well as a ~ 10.6 MDa megacomplex (IV(2) + I + III(2 )+ II)(2) at lower resolution. In megacomplex IV(2 )+ (I + III(2 )+ II)(2), each CIV(2) protomer associates one copy of supercomplex I + III(2) and one copy of CII, forming a half ring-shaped architecture that adapts to the membrane curvature of mitochondrial cristae. Megacomplex (IV(2 )+ I + III(2 )+ II)(2) defines the relative position between neighbouring half rings and maintains the proximity between CIV(2) and CIII(2) cytochrome c binding sites. Our findings expand the current understanding of divergence in eukaryotic electron transport chain organization and how it is related to mitochondrial morphology.

Structures of Tetrahymena thermophila respiratory megacomplexes on the tubular mitochondrial cristae.,Han F, Hu Y, Wu M, He Z, Tian H, Zhou L Nat Commun. 2023 May 29;14(1):2542. doi: 10.1038/s41467-023-38158-5. PMID:37248254^[1]

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