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The whither of bacteriophytochrome‐based near‐infrared fluorescent proteins: Insights from two‐photon absorption spectroscopy
Author(s) -
Lanin Aleksandr A.,
Chebotarev Artem S.,
Barykitalia V.,
Subach Fedor V.,
Zheltikov Aleksei M.
Publication year - 2019
Publication title -
journal of biophotonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 66
eISSN - 1864-0648
pISSN - 1864-063X
DOI - 10.1002/jbio.201800353
Subject(s) - fluorescence , chromophore , absorption (acoustics) , chemistry , emission spectrum , spectroscopy , absorption spectroscopy , fluorescent protein , photochemistry , analytical chemistry (journal) , materials science , spectral line , green fluorescent protein , physics , optics , biochemistry , chromatography , quantum mechanics , astronomy , composite material , gene
We present one‐ and two‐photon‐absorption fluorescence spectroscopic analysis of biliverdin (BV) chromophore–based single‐domain near‐infrared fluorescent proteins (iRFPs). The results of these studies are used to estimate the internal electric fields acting on BV inside iRFPs and quantify the electric dipole properties of this chromophore, defining the red shift of excitation and emission spectra of BV‐based iRFPs. The iRFP studied in this work is shown to fit well the global diagram of the red‐shift tunability of currently available BV‐based iRFPs as dictated by the quadratic Stark effect, suggesting the existence of the lower bound for the strongest red shifts attainable within this family of fluorescent proteins. The absolute value of the two‐photon absorption (TPA) cross section of a fluorescent calcium sensor based on the studied iRFP is found to be significantly larger than the TPA cross sections of other widely used genetically encodable fluorescent calcium sensors.