Tracking conformational dynamics of cohesin with MINFLUX

The DNA contained in each of our cells has a size of about 2 m and is fitted into the nucleus which is about six orders of magnitude smaller.

It is unclear, how this extraordinary compaction is achieved and how the cell can still carry out highly regulated processes like gene expression, DNA replication, and DNA repair in such a dense environment.Cohesin is a protein that has been shown to play an important part in DNA compaction, especially in sister-chromatid cohesion.

Recently, it has been observed that cohesin extrudes loops of DNA to achieve compaction, but how exactly it carries out its function is unknown.Fluorescence spectroscopy is a powerful tool to investigate conformational dynamics of biomolecules. MINFLUX is a recently developed method which localizes single molecules with a precision of a few nanometers.

Here, I propose a new method based on MINFLUX which will allow to track fluorescent labels on large bio-molecular complexes with nanometer spatial and millisecond time resolution.

The method will be used to study conformational dynamics of cohesin in vitro and investigate the mechanism of loop extrusion.