Abstract
AbstractMitochondrial ATP synthases form rows of dimers, which induce membrane curvature to give cristae their characteristic lamellar or tubular morphology. The angle formed between the central stalks of ATP synthase dimers varies between species. Using cryo-electron tomography and sub-tomogram averaging, we determined the structure of the ATP synthase dimer from the nematode wormC. elegansand show that the dimer angle differs from previously determined structures. The consequences of this species-specific difference at the dimer interface were investigated by comparingC. elegansandS. cerevisiaemitochondrial morphology. We reveal thatC. eleganshas a larger ATP synthase dimer angle with more lamellar (flatter) cristae when compared to yeast. The underlying cause of this difference was investigated by generating an atomic model of theC. elegansATP synthase dimer by homology modelling. A comparison of ourC. elegansmodel to an existingS. cerevisiaestructure reveals the presence of extensions and rearrangements inC. eleganssubunits associated with maintaining the dimer interface. We speculate that increasing dimer angles could provide an advantage for species that inhabit variable-oxygen environments by forming flatter more energetically efficient cristae.
Publisher
Cold Spring Harbor Laboratory