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Photoconversion of the fluorescent protein EosFP: a hybrid potential simulation study reveals intersystem crossings.
J Am Chem Soc. 2009 Nov 25; 131(46):16814-23.JA

Abstract

Fluorescent proteins undergoing green to red photoconversion have proved to be essential tools in cell biology, notably in superlocalization nanoscopy. However, the exact mechanism governing photoconversion, which overall involves irreversible cleavage of the protein backbone and elongation of the chromophore pi-conjugation, remains unclear. In this paper we present a theoretical investigation of the photoconversion reaction in the fluorescent protein EosFP, using excited-state hybrid quantum chemical and molecular mechanical potentials, in conjunction with reaction-path-finding techniques. Our results reveal a mechanism in which the hydroxybenzylidene moiety of the chromophore remains protonated and there is an excited state proton transfer from His62 to Phe61 that promotes peptide bond cleavage. Excitation of the neutral green form of EosFP to the first singlet excited state is followed by two intersystem crossing events, first to a triplet state and then back to the ground state singlet surface. From there, a number of rearrangements occur in the ground state and lead to the red form. Analyses of the structures and energies of the intermediates along the reaction path enable us to identify the critical role of the chromophore environment in promoting photoinduced backbone cleavage. Possible ways in which photoconvertible fluorescent proteins can be engineered to facilitate photoconversion are considered.

Authors+Show Affiliations

CNRS, UMR5075, Institut de Biologie Structurale Jean-Pierre Ebel, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19886627

Citation

Lelimousin, Mickaël, et al. "Photoconversion of the Fluorescent Protein EosFP: a Hybrid Potential Simulation Study Reveals Intersystem Crossings." Journal of the American Chemical Society, vol. 131, no. 46, 2009, pp. 16814-23.
Lelimousin M, Adam V, Nienhaus GU, et al. Photoconversion of the fluorescent protein EosFP: a hybrid potential simulation study reveals intersystem crossings. J Am Chem Soc. 2009;131(46):16814-23.
Lelimousin, M., Adam, V., Nienhaus, G. U., Bourgeois, D., & Field, M. J. (2009). Photoconversion of the fluorescent protein EosFP: a hybrid potential simulation study reveals intersystem crossings. Journal of the American Chemical Society, 131(46), 16814-23. https://doi.org/10.1021/ja905380y
Lelimousin M, et al. Photoconversion of the Fluorescent Protein EosFP: a Hybrid Potential Simulation Study Reveals Intersystem Crossings. J Am Chem Soc. 2009 Nov 25;131(46):16814-23. PubMed PMID: 19886627.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photoconversion of the fluorescent protein EosFP: a hybrid potential simulation study reveals intersystem crossings. AU - Lelimousin,Mickaël, AU - Adam,Virgile, AU - Nienhaus,G Ulrich, AU - Bourgeois,Dominique, AU - Field,Martin J, PY - 2009/11/6/entrez PY - 2009/11/6/pubmed PY - 2010/2/10/medline SP - 16814 EP - 23 JF - Journal of the American Chemical Society JO - J. Am. Chem. Soc. VL - 131 IS - 46 N2 - Fluorescent proteins undergoing green to red photoconversion have proved to be essential tools in cell biology, notably in superlocalization nanoscopy. However, the exact mechanism governing photoconversion, which overall involves irreversible cleavage of the protein backbone and elongation of the chromophore pi-conjugation, remains unclear. In this paper we present a theoretical investigation of the photoconversion reaction in the fluorescent protein EosFP, using excited-state hybrid quantum chemical and molecular mechanical potentials, in conjunction with reaction-path-finding techniques. Our results reveal a mechanism in which the hydroxybenzylidene moiety of the chromophore remains protonated and there is an excited state proton transfer from His62 to Phe61 that promotes peptide bond cleavage. Excitation of the neutral green form of EosFP to the first singlet excited state is followed by two intersystem crossing events, first to a triplet state and then back to the ground state singlet surface. From there, a number of rearrangements occur in the ground state and lead to the red form. Analyses of the structures and energies of the intermediates along the reaction path enable us to identify the critical role of the chromophore environment in promoting photoinduced backbone cleavage. Possible ways in which photoconvertible fluorescent proteins can be engineered to facilitate photoconversion are considered. SN - 1520-5126 UR - https://www.unboundmedicine.com/medline/citation/19886627/Photoconversion_of_the_fluorescent_protein_EosFP:_a_hybrid_potential_simulation_study_reveals_intersystem_crossings_ L2 - https://dx.doi.org/10.1021/ja905380y DB - PRIME DP - Unbound Medicine ER -