Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways

文献情報

出版日 2020-09-15

DOI 10.1039/D0CP04265J

インパクトファクター 3.676

著者

Manoj Mandal

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要旨

Low-barrier H-bonds form when the pKa values of the H-bond donor and acceptor moieties are nearly equal. Here, we report redox potential (Em) values along two redox-active low-barrier H-bonds in the water-oxidizing enzyme photosystem II (PSII), using a quantum mechanical/molecular mechanical approach. The low-barrier H-bond between D1-Tyr161 (TyrZ) and D1-His190 is located in the middle of the electron transfer pathway. When the proton is at D1-His190, Em(TyrZ) is the lowest and can serve as an electron donor to the oxidized chlorophyll PD1˙+. Em(TyrZ) and Em(D1-His190) are equal, and the TyrZ⋯D1-His190 pair serves as an electron acceptor to Mn4CaO5 when the proton is at TyrZ. In the low-barrier H-bond between D1-His215 and plastoquinone QB, located at the terminus of the electron transfer pathway, the driving force of electron transfer and electronic coupling between QA and QB are maximized when the proton arrives at QB. It seems likely that local proton transfer along redox-active low-barrier H-bonds can alter the driving force or electronic coupling for electron transfer.

掲載誌

Physical Chemistry Chemical Physics

CiteScore: 5.5

自己引用率: 10.3%

年間論文数: 3036

Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions. The journal has a broad scope and welcomes contributions spanning experiment, theory, computation and data science. Topical coverage includes spectroscopy, dynamics, kinetics, statistical mechanics, thermodynamics, electrochemistry, catalysis, surface science, quantum mechanics, quantum computing and machine learning. Interdisciplinary research areas such as polymers and soft matter, materials, nanoscience, energy, surfaces/interfaces, and biophysical chemistry are welcomed if they demonstrate significant innovation and/or insight into physical chemistry. Joined experimental/theoretical studies are particularly appreciated when complementary and based on up-to-date approaches.