Background: iLOV is a fluorescent flavoprotein engineered from the plant blue light receptor phototropin.
<p/>Results: Structures reveal altered protein-chromophore interactions within the flavin-binding cavity of iLOV when compared with its progenitors. Directed evolution further anchored the chromophore to increase iLOV photostability by an order of magnitude.
<p/>Conclusion: Improving iLOV photostability by constraining its fluorophore establishes a framework for fine-tuning fluorescence.
<p/>Significance: Enhanced photostability increases iLOV utility as an oxygen-independent fluorescent reporter
