High-resolution images discover and capture intricate structure and assembly of the respirasome supercomplex

Amazing stuff!

"... Using cryo-electron tomography, researchers at the University of Basel, Switzerland, have now gained insight into the architecture of mitochondria at unprecedented resolution. ...

They discovered that the proteins responsible for energy generation assemble into large "supercomplexes," which play a crucial role in providing the cell's energy. ...

"Using the electron microscope, individual supercomplexes were clearly visible—we could directly see their structures and how they work. The respiratory supercomplexes pump protons across the mitochondrial membrane. The ATP production complexes, which act similarly to a watermill, use this flow of protons to drive ATP generation." ..."

From the editor's summary and abstract:

"Editor’s summary

The mitochondrial respiratory chain consists of membrane-integral complexes that build up the proton gradient across the membranes of the cristae, thereby powering ATP synthase.

Waltz et al. used cryo–electron tomography to resolve native structures of these complexes directly within the green alga Chlamydomonas reinhardtii. Their findings reveal how respiratory complexes I, III, and IV assemble into a respirasome supercomplex, which is restricted to flat membrane regions apart from rows of ATP synthase at the curved tips of cristae. The work also captures fine structural details of how respirasomes are held together and how electron-carrier proteins bind these assemblies, offering insights into mitochondrial respiration inside native cells. ...

Abstract

Mitochondria regenerate adenosine triphosphate (ATP) through oxidative phosphorylation. This process is carried out by five membrane-bound complexes collectively known as the respiratory chain, working in concert to transfer electrons and pump protons. The precise organization of these complexes in native cells is debated.

We used in situ cryo–electron tomography to visualize the native structures and organization of several major mitochondrial complexes in Chlamydomonas reinhardtii cells. ATP synthases and respiratory complexes segregate into curved and flat crista membrane domains, respectively. Respiratory complexes I, III, and IV assemble into a respirasome supercomplex, from which we determined a native 5-angstrom (Å) resolution structure showing binding of electron carrier cytochrome c. Combined with single-particle cryo–electron microscopy at 2.4-Å resolution, we model how the respiratory complexes organize inside native mitochondria."

High-resolution images capture intricate structure of mitochondrial supercomplexes

The cell’s powerhouses: Molecular machines enable efficient energy production (original news release) "Mitochondria are the powerhouses in our cells, producing the energy for all vital processes. Using cryo-electron tomography, researchers at the University of Basel have now gained insight into the architecture of mitochondria at unprecedented resolution. They discovered that the proteins responsible for energy generation assemble into large “supercomplexes”, which play a crucial role in providing the cell’s energy."

In-cell architecture of the mitochondrial respiratory chain (no public access)

In-cell architecture of the mitochondrial respiratory chain (open access, preprint)

I presume, this image represents the supercomplex (a screenshot take from the linked YouTube video, but the video is without any captions and without any audio, how amateurish)

This is the official image provided. However, I believe this is a sort of artistic rendering and not a real image.