Surface Plasmon Resonance (SPR) is an extremely valuable technique for characterizing molecular interactions. Like most technologies that generate large quantities of data, SPR experiments are made easier with powerful, user-friendly software. The ideal SPR data analysis program not only allows you to collect raw data, but also allows you to analyze the data and create publication-ready graphs in a straightforward way. Reichert has accomplished this goal with a combination of in-house software development, and partnering with an external expert, Ridgeview Instruments AB.
Reichert has developed SPRAutolink, a proprietary software program that makes running experiments and collecting data intuitive. Now, the overlays obtained using SPRAutolink can be directly transferred to a data analysis program called TraceDrawer. You simply obtain your overlays in SPRAutolink, and then with one click transfer them to TraceDrawer for data analysis. TraceDrawer– alignment is straightforward, you can perform background and blank subtractions, and adjust concentrations if needed. Also, when fitting the data, you have a number of kinetics models to choose from. Data can be fit to a 1:1 binding model (with or without mass transport or depletion) or three different 2-site models (2:1 with or without conformational change, or 1:2). You can also fit Dissociation data only. Figure 1 shows results for data fit to a 1:1 binding model.
Figure 1: Data fit to a 1:1 Binding Model in TraceDrawer.
Additionally, if equilibrium responses can be obtained, TraceDrawer can be used for affinity analyses, and to create figures that are of publication quality (see Figure 2).
Figure 2: TraceDrawer can be used for Affinity plots.
Furthermore, TraceDrawer can be used to compare results from different instruments, experiments and operators, making TraceDrawer a powerful way to keep track of all results from a single project. Summaries of ka(association rate constant) an kd(dissociation rate constant) can be presented as on/off plots by clicking the On/off rate map button in the summary tool. Each curve is presented as a coordinate in the ka/kd-space, which enables a fast overview of many compounds.
Figure 3: TraceDrawer creates publication-ready figures, such as this summary of screening of 5 different compounds over the same surface.
We hope you found this post helpful and informative. You can read more about SPR elsewhere on Reichert’s website, including our first blog post, information on the technology of SPR, SPRAutolink and TraceDrawer.
If you would like advice on how best to fit your data, please do not hesitate to contact us. Also, please contact us if you would like to suggest topics for future blog posts or if you have any suggestions to make this column even better.