Cryo-electron tomography of C. elegans mitochondria reveals how the ATP synthase dimer interface shapes crista membranes

Abstract

Mitochondrial ATP synthases form rows of dimers, which induce membrane curvature to give cristae their 18 characteristic lamellar or tubular morphology. The angle formed between the central stalks of ATP synthase 19 dimers varies between species. Using cryo-electron tomography and sub-tomogram averaging, we 20 determined the structure of the ATP synthase dimer from the nematode worm C. elegans. We showed that 21 the angle formed by the ATP synthase dimer is different to previously determined structures. The 22 consequences of species-specific differences at the dimer interface were investigated by comparing 23 mitochondrial morphology between C. elegans and S. cerevisiae. We reveal that a larger ATP synthase 24 dimer angle in C. elegans is consequent with more lamellar (flatter) cristae compared to yeast. The 25 underlying cause of this difference was investigated by generating an atomic model of the C. elegans ATP 26 synthase dimer by homology modelling and comparing it to an existing S.