Mechanism of the Primary Charge Transfer Reaction in the Cytochrome bc1 Complex

Angela M Barragan, Klaus Schulten, Ilia A Solov'yov

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

The bc1 complex is a critical enzyme for the ATP production in photosynthesis and cellular respiration. Its biochemical function relies on the so-called Q-cycle, which is well established and operates via quinol substrates that bind inside the protein complex. Despite decades of research, the quinol-protein interaction, which initiates the Q-cycle, has not yet been completely described. Furthermore, the initial charge transfer reactions of the Q-cycle lack a physical description. The present investigation utilizes classical molecular dynamics simulations in tandem with quantum density functional theory calculations, to provide a complete and consistent quantitative description of the primary events that occur within the bc1 complex upon quinol binding. In particular, the electron and proton transfer reactions that trigger the Q-cycle in the bc1 complex from Rhodobacter capsulatus are studied. The coupled nature of these charge transfer reactions was revealed by obtaining the transition energy path connecting configurations of the Qo-site prior and after the transfers. The analysis of orbitals and partial charge distribution of the different states of the Qo-site has further supported the conclusion. Finally, key structural elements of the bc1 complex that trigger the charge transfer reactions were established, manifesting the importance of the environment in the process, which is furthermore evidenced by free energy calculations.

OriginalsprogEngelsk
TidsskriftThe Journal of Physical Chemistry Part B
Vol/bind120
Udgave nummer44
Sider (fra-til)11369-11380
ISSN1520-6106
DOI
StatusUdgivet - 12. okt. 2016

Fingeraftryk

Hydroquinones
Electron Transport Complex III
cytochromes
Charge transfer
charge transfer
Proteins
cycles
Proton transfer
Photosynthesis
actuators
Adenosinetriphosphate
Charge distribution
proteins
Free energy
Density functional theory
photosynthesis
Molecular dynamics
adenosine triphosphate
respiration
Enzymes

Citer dette

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abstract = "The bc1 complex is a critical enzyme for the ATP production in photosynthesis and cellular respiration. Its biochemical function relies on the so-called Q-cycle, which is well established and operates via quinol substrates that bind inside the protein complex. Despite decades of research, the quinol-protein interaction, which initiates the Q-cycle, has not yet been completely described. Furthermore, the initial charge transfer reactions of the Q-cycle lack a physical description. The present investigation utilizes classical molecular dynamics simulations in tandem with quantum density functional theory calculations, to provide a complete and consistent quantitative description of the primary events that occur within the bc1 complex upon quinol binding. In particular, the electron and proton transfer reactions that trigger the Q-cycle in the bc1 complex from Rhodobacter capsulatus are studied. The coupled nature of these charge transfer reactions was revealed by obtaining the transition energy path connecting configurations of the Qo-site prior and after the transfers. The analysis of orbitals and partial charge distribution of the different states of the Qo-site has further supported the conclusion. Finally, key structural elements of the bc1 complex that trigger the charge transfer reactions were established, manifesting the importance of the environment in the process, which is furthermore evidenced by free energy calculations.",
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Mechanism of the Primary Charge Transfer Reaction in the Cytochrome bc1 Complex. / Barragan, Angela M; Schulten, Klaus; Solov'yov, Ilia A.

I: The Journal of Physical Chemistry Part B, Bind 120, Nr. 44, 12.10.2016, s. 11369-11380.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Mechanism of the Primary Charge Transfer Reaction in the Cytochrome bc1 Complex

AU - Barragan, Angela M

AU - Schulten, Klaus

AU - Solov'yov, Ilia A

PY - 2016/10/12

Y1 - 2016/10/12

N2 - The bc1 complex is a critical enzyme for the ATP production in photosynthesis and cellular respiration. Its biochemical function relies on the so-called Q-cycle, which is well established and operates via quinol substrates that bind inside the protein complex. Despite decades of research, the quinol-protein interaction, which initiates the Q-cycle, has not yet been completely described. Furthermore, the initial charge transfer reactions of the Q-cycle lack a physical description. The present investigation utilizes classical molecular dynamics simulations in tandem with quantum density functional theory calculations, to provide a complete and consistent quantitative description of the primary events that occur within the bc1 complex upon quinol binding. In particular, the electron and proton transfer reactions that trigger the Q-cycle in the bc1 complex from Rhodobacter capsulatus are studied. The coupled nature of these charge transfer reactions was revealed by obtaining the transition energy path connecting configurations of the Qo-site prior and after the transfers. The analysis of orbitals and partial charge distribution of the different states of the Qo-site has further supported the conclusion. Finally, key structural elements of the bc1 complex that trigger the charge transfer reactions were established, manifesting the importance of the environment in the process, which is furthermore evidenced by free energy calculations.

AB - The bc1 complex is a critical enzyme for the ATP production in photosynthesis and cellular respiration. Its biochemical function relies on the so-called Q-cycle, which is well established and operates via quinol substrates that bind inside the protein complex. Despite decades of research, the quinol-protein interaction, which initiates the Q-cycle, has not yet been completely described. Furthermore, the initial charge transfer reactions of the Q-cycle lack a physical description. The present investigation utilizes classical molecular dynamics simulations in tandem with quantum density functional theory calculations, to provide a complete and consistent quantitative description of the primary events that occur within the bc1 complex upon quinol binding. In particular, the electron and proton transfer reactions that trigger the Q-cycle in the bc1 complex from Rhodobacter capsulatus are studied. The coupled nature of these charge transfer reactions was revealed by obtaining the transition energy path connecting configurations of the Qo-site prior and after the transfers. The analysis of orbitals and partial charge distribution of the different states of the Qo-site has further supported the conclusion. Finally, key structural elements of the bc1 complex that trigger the charge transfer reactions were established, manifesting the importance of the environment in the process, which is furthermore evidenced by free energy calculations.

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DO - 10.1021/acs.jpcb.6b07394

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JO - Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical

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