Oligomeric hypercomplex of the complete oxidative phosphorylation system in heart mitochondria.

Abstract

The existence of a complete oxidative phosphorylation system supercomplex including both electron transport system and ATP synthases has long been assumed based on functional evidence. However, no conclusive structural confirmation has been obtained. In this study cryo-electron tomography was used to reveal the supramolecular architecture of the rat heart mitochondria cristae. We show that rows of respiratory chain supercomplexes are connected with rows of ATP synthases forming the oligomeric hypercomplex. The discovered hypercomplexes may increase the effectiveness of oxidative phosphorylation ensuring a direct proton transfer from pumps to ATP synthase along the membrane without energy dissipation.