How FIDA Enhances Protein Projects at Sygnature Discovery

Revolutionising our Protein Science: How FIDA Enhances Protein Projects at Sygnature

Written by Dr Duncan Smith and Dr Martin Jennings

Within the Protein Science and Structural Biology department at Sygnature Discovery, we have been utilising the Fida platform  (Flow Induced Dispersion Analysis) since its launch in 2024. Within six months, it quickly became an essential tool for our team. Fida has contributed as an analytical tool in a number of our protein projects, as well as enabling stand-alone Fida projects. Here we discuss what Fida is, how Fida has helped us to advance our protein science projects, and how it can benefit our clients. We will also showcase some example data generated at Sygnature to illustrate the potential of Fida.

What is Fida?

Fida is a technique which allows the measurement of a biomolecule’s size (typically proteins for us) in solution. This method uses diffusion under laminar flow to mobilise the sample through a capillary, allowing for the calculation of hydrodynamic radius (Rh) from peak width. At Sygnature, we can follow proteins by intrinsic or labelled fluorescence giving experimental flexibility. Fida is incredibly versatile and can provide a wealth of information on particle size, oligomeric state, buffer effects, protein stability, aggregation, and protein-ligand interaction. It is relatively quick to perform with a standard run taking 6 minutes, and some types of experiment can use just nanolitres of sample.

Fida for QC Analysis

We regularly use Fida for QC analysis on proteins purified at Sygnature where Fida offers a quick homogeneity check (Fig. 1), which is particularly useful for proteins that may be prone to aggregation. We also use Fida to check protein stability over time or a freeze/thaw step, including measuring membrane protein solubility and stability where Fida offers an alternative to techniques such as fluorescent size exclusion chromatography (FSEC; Fig. 2). Fida has been especially useful for large species that are too big for SEC, such as megadalton protein complexes or liposomes, providing a complementary technique to obtain valuable data.

Measuring Interactions using Fida

Fida is a powerful tool that can be used to measure interactions in solution by monitoring size changes.Kd values can be estimated by measuring the apparent size of the ligand at different analyte concentrations and plotting a binding curve. We have used Fida to measure protein-protein and protein-DNA interactions (Fig. 3).

Fida is an excellent tool for assessing oligomeric state by measuring the absolute size of the analyte and comparing it to expected/predicted sizes. At Sygnature, we have used this to measure protein self-affinity and establish monomeric conditions (Fig. 4) for in-house crystallography projects.

Where Will Fida Take Us Next

Fida has had a significant impact on most areas of our work. It has been applied to dedicated projects and used as a tool to work smarter, sustaining high interest over multiple projects with several clients. One of the most important features of Fida is its quick time to first result, which allows us to rapidly evaluate protein samples and binding interactions. We can usually determine whether an interaction will be suitable for a Fida study within hours. We have used it to measure protein-protein and protein-ligand interactions, characterise intrinsically disordered proteins, study oligomeric state, and explore PROTACs – and that’s just scratching the surface of Fida’s capabilities, which include applications such measurement of protein aggregation and liquid-liquid phase separation.

Conclusion

Overall, Fida has proven to be an effective, versatile, and valuable platform for the Protein Science and Structural Biology Department at Sygnature Discovery. It has enabled us to advance our protein science projects and offer new capabilities to our clients. We are excited about the future of Fida and the possibilities it holds for our research and our clients.