Steps toward enhancing the fluorescence of small-molecule-based protein labels using supramolecular hosts

Labeling of proteins with small-molecule-based fluorescent probes provides a powerful tool to determine their expression level and localization in living cells. We propose a method for increasing and stabilizing the emission of such probes using supramolecular hosts such as β-cyclodextrin (β-CD). Although the emission of a His-tag binding probe was enhanced in the presence of β-CD, binding of the probe-β-CD complex to a His-tagged protein led to partial β-CD displacement and consequently, a reduction in the emission signal.