Protein-protein interaction measurements are becoming more and more essential to any lab performing proteomics research.
- FCS allows measurement of freely diffusing proteins
FCS is uniquely suited to measure protein-protein interactions in solution because it can differentiate bound and unbound proteins (based on their diffusion rates).
- FCS measures concentration without requiring standard curves
Because FCS directly measures the number of diffusing particles in the detection volume, it provides an accurate measure of concentration without the need for calibration curves. Combining the concentration measurement with the fractional quantification of bound vs unbound protein allows you to easily create binding curves to obtain Km/Ki/Kd values.
- FCS gives you stoichiometry information
If you work with proteins that have multiple binding sites, FCS can give you high-content information about the stoichiometry of binding multiple ways. Proteins bound to multiple proteins diffuse more slowly, have higher counts-per-particle, and result in a larger decrease in total particle number than those bound to only one protein.
Are you using or considering using FCS to measure protein-protein interactions? Are you having any problems? Reply below and let us know!
- FCSXpert Team