Bioinspired Molecular Lantern: Tuning the Firefly Oxyluciferin Emission with Host–Guest Chemistry
journal contributionposted on 21.07.2016 by Na’il Saleh, Abdul Rahman Ba Suwaid, Ahmad Alhalabi, Ahmed Z. A. Abuibaid, Oleg V. Maltsev, Lukas Hintermann, Panče Naumov
Any type of content formally published in an academic journal, usually following a peer-review process.
Fireflies generate flashes of visible light via luciferase-catalyzed chemiexcitation of the substrate (luciferin) to the first excited state of the emitter (oxyluciferin). Microenvironment effects are often invoked to explain the effects of the luciferase active pocket on the emission; however, the exceedingly complex spectrochemistry and synthetic burdens have precluded elucidation of the nature of these interactions. To decipher the effects of microenvironment on the light emission, here the hydrophobic interior of cucurbituril (CB7) is used to mimic the nonpolar active pocket of luciferase. The hydrophobic interior of CB7 induces shifts of the ground-state pKas by 1.9–2.5 units to higher values. Upon sequestration, the emission maxima of neutral firefly oxyluciferin and its conjugate monodeprotonated base are blue-shifted by 40 and 39 nm, respectively, resulting in visual color changes of the emitted light.