Structure of mitochondrial complex elucidated

Research lead

Scientists of the universities of Freiburg and Frankfurt have elucidated the architecture of the largest protein complex in the cellular respiratory chain, uncovering an unknown mechanism of energy conversion that is required to utilise the energy contained in food in the process.

The complex, dubbed mitochondrial complex I, contains more than 40 different proteins, A detailed understanding of the function of the complex is of medical interest, because it is implicated in several neurodegenerative diseases, including as Parkinson’s disease and Alzheimer’s disease, and also with the physiological processes of biological ageing.

The work of Carola Hunte of the Freiburg Institute for Biochemistry and Molecular Biology and the Centre for Biological Signalling Studies in cooperation with Ulrich Brandt, Professor for Molecular Bioenergetics and member of the excellence centre “Macromolecular Complexes”, and his colleague Volker Zickermann is said to be a major step forward to this understanding.

Energy metabolism takes place the mitochondria, which transduce the energy taken up as food into adenosine triphosphate, (ATP), the universal cellular energy source. The production of ATP in mitochondria requires many steps.

The structural model drawn up by the researchers provides important and unexpected insights into the function of complex I. A special type of “transmission element”, which is not known from any other protein, appears to be responsible for the energy transduction within the complex, by mechanical nanoscale coupling.

This is analogous to power transmission by a coupling rod, such as for example in connecting the wheels of a steam train.

This new nano-mechanical principle will now be analysed by additional functional studies and a refined structural analysis.