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Fluorescence Quenching of (Dimethylamino)naphthalene Dyes Badan and Prodan by Tryptophan in Cytochromes P450 and Micelles

Pospíšil, Petr and Luxem, Katja E. and Ener, Maraia and Sýkora, Jan and Kocábová, Jana and Gray, Harry B. and Vlček, Antonín, Jr. and Hof, Martin (2014) Fluorescence Quenching of (Dimethylamino)naphthalene Dyes Badan and Prodan by Tryptophan in Cytochromes P450 and Micelles. Journal of Physical Chemistry B, 118 (34). pp. 10085-10091. ISSN 1520-6106. PMCID PMC4148165. doi:10.1021/jp504625d.

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Fluorescence of 2-(N,N-dimethylamino)-6-propionylnaphthalene dyes Badan and Prodan is quenched by tryptophan in Brij 58 micelles as well as in two cytochrome P450 proteins (CYP102, CYP119) with Badan covalently attached to a cysteine residue. Formation of nonemissive complexes between a dye molecule and tryptophan accounts for about 76% of the fluorescence intensity quenching in micelles, the rest is due to diffusive encounters. In the absence of tryptophan, fluorescence of Badan-labeled cytochromes decays with triexponential kinetics characterized by lifetimes of about 100 ps, 700–800 ps, and 3 ns. Site mutation of a histidine residue in the vicinity of the Badan label by tryptophan results in shortening of all three decay lifetimes. The relative amplitude of the fastest component increases at the expense of the two slower ones. The average quenching rate constants are 4.5 × 10^8 s^–1 (CYP102) and 3.7 × 10^8 s^–1 (CYP119), at 288 K. Cyclic voltammetry of Prodan in MeCN shows a reversible reduction peak at −1.85 V vs NHE that becomes chemically irreversible and shifts positively upon addition of water. A quasireversible reduction at −0.88 V was observed in an aqueous buffer (pH 7.3). The excited-state reduction potential of Prodan (and Badan) is estimated to vary from about +0.6 V (vs NHE) in polar aprotic media (MeCN) to approximately +1.6 V in water. Tryptophan quenching of Badan/Prodan fluorescence in CYPs and Brij 58 micelles is exergonic by ≤0.5 V and involves tryptophan oxidation by excited Badan/Prodan, coupled with a fast reaction between the reduced dye and water. Photoreduction is a new quenching mechanism for 2-(N,N-dimethylamino)-6-propionylnaphthalene dyes that are often used as solvatochromic polarity probes, FRET donors and acceptors, as well as reporters of solvation dynamics.

Item Type:Article
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URLURL TypeDescription Information CentralArticle
Sýkora, Jan0000-0003-0936-9368
Gray, Harry B.0000-0002-7937-7876
Hof, Martin0000-0003-2884-3037
Additional Information:© 2014 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Received: May 11, 2014; Revised: July 7, 2014; Published: July 31, 2014. This research was supported by the Grant Agency of the Czech Republic (P106/12/G016) and the Ministry of Education of the Czech Republic program Kontakt II (grant LH13015). M.H. acknowledges financial support by ASCR via the Praemium Academiae award. Work at Caltech was supported by NIH grant DK019038 to H.B.G. and a Summer Undergraduate Research Fellowship (SURF) to K.E.L.
Funding AgencyGrant Number
Czech Republic Grant AgencyP106/12/G016
Czech Republic Ministry of Education Program Kontakt IILH13015
ASCR Praemium Academiae awardUNSPECIFIED
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Issue or Number:34
PubMed Central ID:PMC4148165
Record Number:CaltechAUTHORS:20140926-090835212
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Official Citation:Fluorescence Quenching of (Dimethylamino)naphthalene Dyes Badan and Prodan by Tryptophan in Cytochromes P450 and Micelles Petr Pospíšil, Katja E. Luxem, Maraia Ener, Jan Sýkora, Jana Kocábová, Harry B. Gray, Antonín Vlček, Jr., and Martin Hof The Journal of Physical Chemistry B 2014 118 (34), 10085-10091
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50051
Deposited By: Jason Perez
Deposited On:29 Sep 2014 17:03
Last Modified:10 Nov 2021 18:51

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