Molecule of the Month: Respiratory Supercomplex
In our mitochondria, three electron-transport complexes assemble into a supercomplex.
Why Team Up?
Evolution of Mitochondria
Exploring the Structure
Four Views of Respirasome Structure
The resolution revolution of cryoelectron microscopy is now making it possible to see these enormous supercomplexes in detail. Four different coloring schemes are used here to reveal different functional features of the respirasome. The first view colors the complexes by hydrophobicity to reveal the belt of carbon-rich amino acids (yellow) that localize the complexes in the mitochondrial membrane. Another view shows the many cofactors that shuttle electrons through the complexes and ultimately place them on oxygen molecules. The two at the bottom show the mitochondria-encoded subunits and the core subunits, which form the central structure of each complex. To explore these views in more detail, click on the image for an interactive JSmol.
Topics for Further Discussion
- Even larger respiratory supercomplexes have also been observed. For example, take a look at the “megacomplex” in PDB ID 5xti.
- You can explore the cryoEM map for these supercomplexes at the Electron Microscopy Data Bank. For example, take a look at the map for the respirasome.
Related PDB-101 Resources
- Browse Biological Energy
- Vercellino, I., Sazanov, L.A. (2022) The assembly, regulation and function of the mitochondrial respiratory chain. Nat Rev Mol Cell Biol 23: 141-161
- 7o37: Vercellino, I., Sazanov, L.A. (2021) Structure and assembly of the mammalian mitochondrial supercomplex CIII2CIV. Nature 598: 364-367
- 5xth: Guo, R., Zong, S., Wu, M., Gu, J., Yang, M. (2017) Architecture of Human Mitochondrial Respiratory Megacomplex I2III2IV2. Cell 170: 1247-1257.e12
- 1zoy: Sun, F., Huo, X., Zhai, Y., Wang, A., Xu, J., Su, D., Bartlam, M., Rao, Z. (2005) Crystal Structure of Mitochondrial Respiratory Membrane Protein Complex II. Cell 121: 1043-1057
September 2022, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2022_9