Leonid Sazanov is a structural biologist and biochemist who explores structure and function of large membrane protein complexes from the domain of bioenergetics. These molecular machines interconvert redox energy and proton motive force across biological membranes using a variety of intricate mechanisms.

Leonid is known for the discovery of the first atomic structure of respiratory complex I, using X-ray crystallography and the bacterial enzyme as a model. It is an entry point into the respiratory chain, responsible for most of the energy production in the cell. The complex I structure revealed many unexpected and unique features of this extravagantly elaborate membrane protein assembly. Leonid then went on to determine the first complete atomic structure of the even larger mammalian mitochondrial complex I, using new cryo-EM methods.

Currently Leonid is continuing research into the enigmatic coupling mechanism of complex I using a combination of structural and biophysical techniques. He is also interested in the structure and mechanism of other membrane-embedded molecular machines in mitochondria and bacteria. He was elected to EMBO, the European Molecular Biology Organization, in 2018.