Are there fluorescent dyes than can be used for Differential Scanning Fluorimetry (DSF) of Membrane Proteins?

If your membrane protein has fluorescent residues (tryptophan and tyrosine), you should consider trying our Prometheus NT.plex for DSF using intrinsic protein fluorescence (NanoDSF).

However, if you wish to do conventional DSF (dye-based), please note that many hydrophobic dyes, such as Sypro Orange, cannot be used for Differential Scanning Fluorimetry of membrane proteins, dues to high background staining. However, if your membrane protein has buried cysteines, then a cysteine-reactive dye may work. BODIPY FL-cysteine can be used, since it has excitation and emission wavelengths within the standard range of many qPCR instruments, including our QuantStudio 6/7.  CPM (a courmarin derivative) was one of the earlier dyes used for this purpose, however many modern qPCR instruments no longer have excitation filters appropriate for this dye.

General Experimental Conditions for Conventional DSF using BODIPY FL-cysteine:

• Alkylate exposed free thiols with Iodoacetamide prior to adding cysteine-reactive dye, so as to block background staining (1mg/ml iodoacetamide).
• Label with BODIPY FL-cysteine at a final concentration of 2 µM dye.
• 25 °C - 99 °C temperature ramp, with ramp rate of 1 °C/minute.
• 470 +/- 15 nm excitation and 520 +/- 15 nm emission filters. 

References:

• Bergsdorf, C. et al. An Alternative Thiol-Reactive Dye to Analyze Ligand Interactions with the Chemokine Receptor CXCR2 Using a New Thermal Shift Assay Format. Slas Discov 21, 243–251 (2016).
• Wingler, L. M. et al. Angiotensin and biased analogs induce structurally distinct active conformations within a GPCR. Science 367, 888–892 (2020). Adaptation by CMI User, Meredith Skiba from the Kruse lab.