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Super Time-resolved Fluorescence Anisotropy with Switchable States

Project description

The lights never go down on the best protein show in town

Proteins are the main enablers of practically every process in a cell and between cells, directly or indirectly. Their complex 3D structures play a fundamental role in their dynamic interactions with the molecules around them, and that conformation changes in time and according to need. The ability to characterise protein-protein interactions and protein conformational changes in time is critical to our understanding of the body in health and disease. Fluorescence anisotropy does just that, measuring changes in absorption and emission from a fluorophore to detect the changing orientation of a molecule in space. However, the 'video' is shut down when the fluorescence lifetime is reached – very quickly. The EU-funded STARSS project plans to revolutionise the technique with reversibly switchable fluorescent transitions that will keep the coverage coming with practically no upper limit on molecular size.


Viable experimental techniques able to reveal and quantify protein-protein interactions and protein conformational changes can have a significant impact on cell biology and drug discovery. Fluorescence anisotropy (FA) has been widely employed in biomedical research as a tool for high-throughput screening applications, to study the binding of small molecules to protein and characterize protein-protein interaction. Despite the enormous potential of the FA technique, the major limiting factor is the inability of probing the system past the fluorescence lifetime, which in the most favorable cases lasts for a few nanoseconds, setting an upper limit to the time scales that can be addressed with the technique, which translates in an upper limit of few nanometers of molecular size.
Reversibly switchable fluorescent transitions have the potential to revolutionize the capability of FA tools for the study of large molecular aggregates, overcoming the limits imposed by the finite fluorescence lifetime, and providing a practical and highly sensible way of measuring rotational diffusion processes with a practically unlimited upper bound on molecular sizes.
This proposal aims to develop a novel fluorescent anisotropy technique, named Super Time-resolved Anisotropy with Reversibly Switchable States (STARSS), designed to measure rotational mobility all-across the time scale from nano- to micro-seconds, which will enable to discern clusters from free rotating molecules in situ and with high angular precision. The coupling of STARSS observables and microscopy will provide a powerful tool to reveal the dynamics of protein complexes inside the compartments of living cells, shedding new light on a multitude of biological processes.


Net EU contribution
€ 191 852,16
Brinellvagen 8
100 44 Stockholm

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Östra Sverige Stockholm Stockholms län
Activity type
Higher or Secondary Education Establishments
Other funding
€ 0,00