Visible fluorescent proteins for FRET

This chapter discusses the use of Visible fluorescent proteins (VFPs) for FRET studies, a comprehensive table with Förster radii of VFP pairs is presented and recommendations for choosing the right pairs are made. The chapter discusses VFPs that are used for studies that use fluorescence resonance energy transfer (FRET) to detect molecular interactions and molecular conformations. Recommendations for choosing the right pair of VFPs for FRET are made and some examples of the application of VFPs in FRET-based imaging are highlighted. The chapter presents the properties of several VFP pairs. The chapter discusses the most blue-shifted pair, such as, BFP-GFP, and then move towards the red part of the spectrum, subsequently highlighting, such as, CFP-YFP, GFP-RFP, YFP-RFP, and OFP-RFP pairs. The most widely used CFP/ YFP pair is still a good choice when nonsticky and optimized variants are used (e.g., SCFP3A-SYFP2), and the future holds great promise for novel red-shifted pairs to study protein-protein interactions, mainly because of the increased Förster radius.