Mancini, Daiana T.; Sen, Kakali; Barbatti, Mario; Thiel, Walter; Ramalho, Teodorico C.
Excited-State Proton Transfer Can Tune the Color of Protein Fluorescent Markers
CHEMPHYSCHEM, 16:3444-3449, NOV 16 2015

We show by quantum mechanical/molecular mechanical (QM/MM) simulations that phenylbenzothiazoles undergoing an excited-state proton transfer (ESPT) can be used to probe protein binding sites. For 2-(2'-hydroxy-4'-aminophenyl)benzothiazole (HABT) bound to a tyrosine kinase, the absolute and relative intensities of the fluorescence bands arising from the enol and keto forms are found to be strongly dependent on the active-site conformation. The emission properties are tuned by hydrogen-bonding interactions of HABT with the neighboring amino acid T766 and with active-site water. The use of ESPT tuners opens the possibility of creating two-color fluorescent markers for protein binding sites, with potential applications in the detection of mutations in cancer cell lines.

DOI:10.1002/cphc.201500744

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