Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives

Electron transfer within and between proteins is a fundamental biological phenomenon, in which efficiency depends on several physical parameters. We have engineered a number of horse heart cytochrome <i>c</i> single-point mutants with cysteine substitutions at various positions of the pr...

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Autores principales:	Petro Khoroshyy, Katalin Tenger, Rita V. Chertkova, Olga V. Bocharova, Mikhail P. Kirpichnikov, Natalia Borovok, Géza I. Groma, Dmitry A. Dolgikh, Alexander B. Kotlyar, László Zimányi
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	cytochrome <i>c</i> intramolecular electron transfer TUPS time-resolved spectroscopy triplet excited state Organic chemistry QD241-441
Acceso en línea:	https://doaj.org/article/25d90bdee2794967bf347ec6ed75cffa
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spelling	oai:doaj.org-article:25d90bdee2794967bf347ec6ed75cffa2021-11-25T18:28:52ZKinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives10.3390/molecules262269761420-3049https://doaj.org/article/25d90bdee2794967bf347ec6ed75cffa2021-11-01T00:00:00Zhttps://www.mdpi.com/1420-3049/26/22/6976https://doaj.org/toc/1420-3049Electron transfer within and between proteins is a fundamental biological phenomenon, in which efficiency depends on several physical parameters. We have engineered a number of horse heart cytochrome <i>c</i> single-point mutants with cysteine substitutions at various positions of the protein surface. To these cysteines, as well as to several native lysine side chains, the photoinduced redox label 8-thiouredopyrene-1,3,6-trisulfonate (TUPS) was covalently attached. The long-lived, low potential triplet excited state of TUPS, generated with high quantum efficiency, serves as an electron donor to the oxidized heme <i>c</i>. The rates of the forward (from the label to the heme) and the reverse (from the reduced heme back to the oxidized label) electron transfer reactions were obtained from multichannel and single wavelength flash photolysis absorption kinetic experiments. The electronic coupling term and the reorganization energy for electron transfer in this system were estimated from temperature-dependent experiments and compared with calculated parameters using the crystal and the solution NMR structure of the protein. These results together with the observation of multiexponential kinetics strongly support earlier conclusions that the flexible arm connecting TUPS to the protein allows several shortcut routes for the electron involving through space jumps between the label and the protein surface.Petro KhoroshyyKatalin TengerRita V. ChertkovaOlga V. BocharovaMikhail P. KirpichnikovNatalia BorovokGéza I. GromaDmitry A. DolgikhAlexander B. KotlyarLászló ZimányiMDPI AGarticlecytochrome <i>c</i>intramolecular electron transferTUPStime-resolved spectroscopytriplet excited stateOrganic chemistryQD241-441ENMolecules, Vol 26, Iss 6976, p 6976 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	cytochrome <i>c</i> intramolecular electron transfer TUPS time-resolved spectroscopy triplet excited state Organic chemistry QD241-441
spellingShingle	cytochrome <i>c</i> intramolecular electron transfer TUPS time-resolved spectroscopy triplet excited state Organic chemistry QD241-441 Petro Khoroshyy Katalin Tenger Rita V. Chertkova Olga V. Bocharova Mikhail P. Kirpichnikov Natalia Borovok Géza I. Groma Dmitry A. Dolgikh Alexander B. Kotlyar László Zimányi Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives
description	Electron transfer within and between proteins is a fundamental biological phenomenon, in which efficiency depends on several physical parameters. We have engineered a number of horse heart cytochrome <i>c</i> single-point mutants with cysteine substitutions at various positions of the protein surface. To these cysteines, as well as to several native lysine side chains, the photoinduced redox label 8-thiouredopyrene-1,3,6-trisulfonate (TUPS) was covalently attached. The long-lived, low potential triplet excited state of TUPS, generated with high quantum efficiency, serves as an electron donor to the oxidized heme <i>c</i>. The rates of the forward (from the label to the heme) and the reverse (from the reduced heme back to the oxidized label) electron transfer reactions were obtained from multichannel and single wavelength flash photolysis absorption kinetic experiments. The electronic coupling term and the reorganization energy for electron transfer in this system were estimated from temperature-dependent experiments and compared with calculated parameters using the crystal and the solution NMR structure of the protein. These results together with the observation of multiexponential kinetics strongly support earlier conclusions that the flexible arm connecting TUPS to the protein allows several shortcut routes for the electron involving through space jumps between the label and the protein surface.
format	article
author	Petro Khoroshyy Katalin Tenger Rita V. Chertkova Olga V. Bocharova Mikhail P. Kirpichnikov Natalia Borovok Géza I. Groma Dmitry A. Dolgikh Alexander B. Kotlyar László Zimányi
author_facet	Petro Khoroshyy Katalin Tenger Rita V. Chertkova Olga V. Bocharova Mikhail P. Kirpichnikov Natalia Borovok Géza I. Groma Dmitry A. Dolgikh Alexander B. Kotlyar László Zimányi
author_sort	Petro Khoroshyy
title	Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives
title_short	Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives
title_full	Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives
title_fullStr	Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives
title_full_unstemmed	Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives
title_sort	kinetics and energetics of intramolecular electron transfer in single-point labeled tups-cytochrome <i>c</i> derivatives
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/25d90bdee2794967bf347ec6ed75cffa
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Kinetics and Energetics of Intramolecular Electron Transfer in Single-Point Labeled TUPS-Cytochrome <i>c</i> Derivatives

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