You can tag the peptide or a small molecule with Alexa 488 fluorophore (similar as fluorescein), similar wavelength as YFP and can do BRET with Rlu-tagged proteins. It is a challenge to label the peptide with Rlu or YFP. If you really want to do an interaction between two small molecule or two peptides, the ideal way to pursue is FRET studies, by incorporating two different fluorophores (one as donor and another as acceptor). I hope this answer your question.
2018-04-11 11:18:36