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Identifying involvement of Lys251/Asp252 pair in electron transfer and associated proton transfer at the quinone reduction site of Rhodobacter capsulatus cytochrome bc1

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Identifying involvement of Lys251/Asp252 pair in electron transfer and associated proton transfer at the quinone reduction site of Rhodobacter capsulatus cytochrome bc1. / Kuleta, Patryk; Sarewicz, Marcin; Postila, Pekka; Róg, Tomasz; Osyczka, Artur.

In: Biochimica et Biophysica Acta: Bioenergetics, Vol. 1857, No. 10, 01.10.2016, p. 1661-1668.

Research output: Contribution to journalArticleScientificpeer-review

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Kuleta, P, Sarewicz, M, Postila, P, Róg, T & Osyczka, A 2016, 'Identifying involvement of Lys251/Asp252 pair in electron transfer and associated proton transfer at the quinone reduction site of Rhodobacter capsulatus cytochrome bc1', Biochimica et Biophysica Acta: Bioenergetics, vol. 1857, no. 10, pp. 1661-1668. https://doi.org/10.1016/j.bbabio.2016.07.003

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Kuleta, Patryk ; Sarewicz, Marcin ; Postila, Pekka ; Róg, Tomasz ; Osyczka, Artur. / Identifying involvement of Lys251/Asp252 pair in electron transfer and associated proton transfer at the quinone reduction site of Rhodobacter capsulatus cytochrome bc1. In: Biochimica et Biophysica Acta: Bioenergetics. 2016 ; Vol. 1857, No. 10. pp. 1661-1668.

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@article{4f0ad68202cf4d5a8dcfd5ec6903d65a,
title = "Identifying involvement of Lys251/Asp252 pair in electron transfer and associated proton transfer at the quinone reduction site of Rhodobacter capsulatus cytochrome bc1",
abstract = "Describing dynamics of proton transfers in proteins is challenging, but crucial for understanding processes which use them for biological functions. In cytochrome bc1, one of the key enzymes of respiration or photosynthesis, proton transfers engage in oxidation of quinol (QH2) and reduction of quinone (Q) taking place at two distinct catalytic sites. Here we evaluated by site-directed mutagenesis the contribution of Lys251/Asp252 pair (bacterial numbering) in electron transfers and associated with it proton uptake to the quinone reduction site (Qi site). We showed that the absence of protonable group at position 251 or 252 significantly changes the equilibrium levels of electronic reactions including the Qi-site mediated oxidation of heme bH, reverse reduction of heme bH by quinol and heme bH/Qi semiquinone equilibrium. This implicates the role of H-bonding network in binding of quinone/semiquinone and defining thermodynamic properties of Q/SQ/QH2 triad. The Lys251/Asp252 proton path is disabled only when both protonable groups are removed. With just one protonable residue from this pair, the entrance of protons to the catalytic site is sustained, albeit at lower rates, indicating that protons can travel through parallel routes, possibly involving water molecules. This shows that proton paths display engineering tolerance for change as long as all the elements available for functional cooperation secure efficient proton delivery to the catalytic site.",
keywords = "Cytochrome bc, Electron transfer, Mitochondrial complex III, Proton transfer, Quinone",
author = "Patryk Kuleta and Marcin Sarewicz and Pekka Postila and Tomasz R{\'o}g and Artur Osyczka",
note = "EXT={"}Postila, Pekka{"}",
year = "2016",
month = "10",
day = "1",
doi = "10.1016/j.bbabio.2016.07.003",
language = "English",
volume = "1857",
pages = "1661--1668",
journal = "Biochimica et Biophysica Acta: Bioenergetics",
issn = "0005-2728",
publisher = "Elsevier",
number = "10",

}

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TY - JOUR

T1 - Identifying involvement of Lys251/Asp252 pair in electron transfer and associated proton transfer at the quinone reduction site of Rhodobacter capsulatus cytochrome bc1

AU - Kuleta, Patryk

AU - Sarewicz, Marcin

AU - Postila, Pekka

AU - Róg, Tomasz

AU - Osyczka, Artur

N1 - EXT="Postila, Pekka"

PY - 2016/10/1

Y1 - 2016/10/1

N2 - Describing dynamics of proton transfers in proteins is challenging, but crucial for understanding processes which use them for biological functions. In cytochrome bc1, one of the key enzymes of respiration or photosynthesis, proton transfers engage in oxidation of quinol (QH2) and reduction of quinone (Q) taking place at two distinct catalytic sites. Here we evaluated by site-directed mutagenesis the contribution of Lys251/Asp252 pair (bacterial numbering) in electron transfers and associated with it proton uptake to the quinone reduction site (Qi site). We showed that the absence of protonable group at position 251 or 252 significantly changes the equilibrium levels of electronic reactions including the Qi-site mediated oxidation of heme bH, reverse reduction of heme bH by quinol and heme bH/Qi semiquinone equilibrium. This implicates the role of H-bonding network in binding of quinone/semiquinone and defining thermodynamic properties of Q/SQ/QH2 triad. The Lys251/Asp252 proton path is disabled only when both protonable groups are removed. With just one protonable residue from this pair, the entrance of protons to the catalytic site is sustained, albeit at lower rates, indicating that protons can travel through parallel routes, possibly involving water molecules. This shows that proton paths display engineering tolerance for change as long as all the elements available for functional cooperation secure efficient proton delivery to the catalytic site.

AB - Describing dynamics of proton transfers in proteins is challenging, but crucial for understanding processes which use them for biological functions. In cytochrome bc1, one of the key enzymes of respiration or photosynthesis, proton transfers engage in oxidation of quinol (QH2) and reduction of quinone (Q) taking place at two distinct catalytic sites. Here we evaluated by site-directed mutagenesis the contribution of Lys251/Asp252 pair (bacterial numbering) in electron transfers and associated with it proton uptake to the quinone reduction site (Qi site). We showed that the absence of protonable group at position 251 or 252 significantly changes the equilibrium levels of electronic reactions including the Qi-site mediated oxidation of heme bH, reverse reduction of heme bH by quinol and heme bH/Qi semiquinone equilibrium. This implicates the role of H-bonding network in binding of quinone/semiquinone and defining thermodynamic properties of Q/SQ/QH2 triad. The Lys251/Asp252 proton path is disabled only when both protonable groups are removed. With just one protonable residue from this pair, the entrance of protons to the catalytic site is sustained, albeit at lower rates, indicating that protons can travel through parallel routes, possibly involving water molecules. This shows that proton paths display engineering tolerance for change as long as all the elements available for functional cooperation secure efficient proton delivery to the catalytic site.

KW - Cytochrome bc

KW - Electron transfer

KW - Mitochondrial complex III

KW - Proton transfer

KW - Quinone

U2 - 10.1016/j.bbabio.2016.07.003

DO - 10.1016/j.bbabio.2016.07.003

M3 - Article

VL - 1857

SP - 1661

EP - 1668

JO - Biochimica et Biophysica Acta: Bioenergetics

JF - Biochimica et Biophysica Acta: Bioenergetics

SN - 0005-2728

IS - 10

ER -