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Excited‐State Proton Transfer Can Tune the Color of Protein Fluorescent Markers
Author(s) -
Mancini Daiana T.,
Sen Kakali,
Barbatti Mario,
Thiel Walter,
Ramalho Teodorico C.
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201500744
Subject(s) - fluorescence , benzothiazole , excited state , chemistry , bimolecular fluorescence complementation , hydrogen bond , photochemistry , enol , proton , fluorescent protein , active site , biophysics , green fluorescent protein , molecule , biochemistry , enzyme , atomic physics , physics , organic chemistry , quantum mechanics , gene , yeast , biology , catalysis
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.