PhD lecture by Shuo Wang, Monday July 31, 10 am, room 9.120

July 17, 2023 / Biophyscis Group

Title: Spatiotemporal stop-and-go dynamics of the mitochondrial TOM core complex correlates with channel activity.

Single-molecule studies can reveal phenomena that remain hidden in ensemble measurements. In her seminar, Shuo will talk about how total internal reflection fluorescence (TIRF) microscopy can be used to study the correlation between lateral protein diffusion and channel activity of the mitochondrial general protein import pore (TOM-CC) in membranes resting on ultrathin hydrogel films.

Using electrode-free optical recordings of ion flux, it will be shown that TOM-CC switches reversibly between three states of ion permeability associated with protein diffusion. While freely diffusing TOM-CC molecules are predominantly in a high permeability state, non-mobile molecules are mostly in an intermediate or low permeability state. This behavior can be explained by the mechanical binding of the two protruding Tom22 subunits to the hydrogel and a concomitant combinatorial opening and closing of the two β-barrel pores of TOM-CC. TOM-CC is thus the first β-barrel membrane protein complex to exhibit membrane state-dependent mechanosensitive properties.



Biophysics Group, Institute of Biomaterials and biomolecular Systems, University of Stuttgart

Pfaffenwaldring 57 , D-70569 Stuttgart, Germany

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