Energy conservation in biological membranes

The respiratory chain of mitochondria and aerobic bacteria is composed of membrane-bound enzymes that transfer electrons from e.g. NADH to O2, which is reduced to H2O.

Sequential electron transfer through these enzyme complexes is linked to transmembrane proton translocation, which maintains an electrochemical proton gradient that is used to store free energy.

In mitochondria, the electron and proton flux through the respiratory chain is regulated by interactions between the components, structural changes, modulation of subunit isoforms and binding of regulatory proteins or small molecules.

The aim of the current project is to understand overall function of the respiratory chain at a molecular level in terms of physical mechanisms.We investigate pathways, kinetics and thermodynamics of electron and proton transfer reactions between and within the respiratory complexes, and study how these processes are regulated by intercomplex interactions.

The studies are focused on supercomplexes, i.e. supramolecular assemblies of respiratory chain complexes from bacteria and mitochondria, as well as intact respiratory membranes.

A wide range of biochemical and biophysical techniques are used (several of these developed by us), combined with the use of single-particle cryogenic electron microscopy and theory.