Flavoproteins, containing flavin chromophores, are enzymes capable of transferring electrons at very high speeds. The ultrafast photoinduced electron-transfer (ET) kinetics of riboflavin binding protein to the excited riboflavin was studied by femtosecond spectroscopy and found to occur within a few hundred femtoseconds [Zhong and Zewail, Proc. Natl. Acad. Sci. U.S.A.2001, 98, 11867–11872]. This ultrafast kinetics was attributed to the presence of two aromatic rings that could transfer the electron to riboflavin: the side chains of tryptophan 156 and tyrosine 75. However, the underlying ET mechanism remained unclear. Here, using a hybrid quantum mechanical–molecular dynamics approach, we perform ET dynamics simulations taking into account the motion of the protein and the solvent upon ET. This approach reveals that ET occurs via a major reaction channel involving tyrosine 75 (83%) and a minor one involving tryptophan 156 (17%). We also show that the protein environment is designed to ensure the fast quenching of the riboflavin excited state.

Zanetti-Polzi, L., Aschi, M., Amadei, A., Daidone, I. (2017). Alternative Electron- Transfer Channels Ensure Ultrafast Deactivation of Light-Induced Ex- cited States in Riboflavin Binding Protein. THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 8(14), 3321-3327 [10.1021/acs.jpclett.7b01575].

Alternative Electron- Transfer Channels Ensure Ultrafast Deactivation of Light-Induced Ex- cited States in Riboflavin Binding Protein

A. Amadei
Membro del Collaboration Group
;
2017-01-01

Abstract

Flavoproteins, containing flavin chromophores, are enzymes capable of transferring electrons at very high speeds. The ultrafast photoinduced electron-transfer (ET) kinetics of riboflavin binding protein to the excited riboflavin was studied by femtosecond spectroscopy and found to occur within a few hundred femtoseconds [Zhong and Zewail, Proc. Natl. Acad. Sci. U.S.A.2001, 98, 11867–11872]. This ultrafast kinetics was attributed to the presence of two aromatic rings that could transfer the electron to riboflavin: the side chains of tryptophan 156 and tyrosine 75. However, the underlying ET mechanism remained unclear. Here, using a hybrid quantum mechanical–molecular dynamics approach, we perform ET dynamics simulations taking into account the motion of the protein and the solvent upon ET. This approach reveals that ET occurs via a major reaction channel involving tyrosine 75 (83%) and a minor one involving tryptophan 156 (17%). We also show that the protein environment is designed to ensure the fast quenching of the riboflavin excited state.
2017
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore CHIM/02 - CHIMICA FISICA
English
Con Impact Factor ISI
Zanetti-Polzi, L., Aschi, M., Amadei, A., Daidone, I. (2017). Alternative Electron- Transfer Channels Ensure Ultrafast Deactivation of Light-Induced Ex- cited States in Riboflavin Binding Protein. THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 8(14), 3321-3327 [10.1021/acs.jpclett.7b01575].
Zanetti-Polzi, L; Aschi, M; Amadei, A; Daidone, I
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/201618
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