Manganese Proteins with Mono‐ &amp; Dinuclear Sites

Penner‐Hahn, James E.

doi:10.1002/0470862106.ia129

Cited by 3 publications

(5 citation statements)

References 28 publications

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“…Electronic coupling is treated as in electron-transfer theory as an electrostatic perturbation that leads to donoracceptor electronic wave function mixing. The resulting resonance energy, the electron-transfer matrix element V ET , is given by Equation (13) in which y A and y D are the electronic wave functions for the acceptor and donor orbitals, respectively, and H is the operator mixing the states.…”

Section: Theory Of Coupled Electron-proton Transfermentioning

confidence: 99%

“…From earlier EXAFS results on S 1 , it was proposed that the OEC is composed of two to three di-m-oxido Mn units with Mn···Mn separation distances of around 2.7 . [9,13,[148][149][150][151] A recent extended range EXAFS study on S 1 revealed three Mn···Mn vectors in the {CaMn 3 } cluster, two of around 2.7 and one of approximately 2.8 , as well as another one or two Mn···Mn interactions with a separation of 3.3 . [152] Even more recently, the structure of S 1 was investigated by EXAFS measurements on single crystals free of radiation damage.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…reaction reduce a benzoquinone to hydroquinone and transfer reductive equivalents to photosystem I, where they enter the Calvin cycle for reduction of CO 2 . [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Recent advances, especially the results of X-ray structures of PSII from cyanobacterium Thermosynechococcus elon-gates at 3-and 3.5-resolution, have given insight at the molecular level into how O 2 is formed in PSII. [16][17][18][19][20][21][22][23] It is known that oxygen is evolved after the sequential absorption of four photons (Kok cycle).…”

Section: Introductionmentioning

confidence: 99%

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The Possible Role of Proton‐Coupled Electron Transfer (PCET) in Water Oxidation by Photosystem II

2007

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All higher life forms use oxygen and respiration as their primary energy source. The oxygen comes from water by solar-energy conversion in photosynthetic membranes. In green plants, light absorption in photosystem II (PSII) drives electron-transfer activation of the oxygen-evolving complex (OEC). The mechanism of water oxidation by the OEC has long been a subject of great interest to biologists and chemists. With the availability of new molecular-level protein structures from X-ray crystallography and EXAFS, as well as the accumulated results from numerous experiments and theoretical studies, it is possible to suggest how water may be oxidized at the OEC. An integrated sequence of light-driven reactions that exploit coupled electron-proton transfer (EPT) could be the key to water oxidation. When these reactions are combined with long-range proton transfer (by sequential local proton transfers), it may be possible to view the OEC as an intricate structure that is "wired for protons".

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Section: Theory Of Coupled Electron-proton Transfermentioning

confidence: 99%

Section: Angewandte Chemiementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Possible Role of Proton‐Coupled Electron Transfer (PCET) in Water Oxidation by Photosystem II

2007

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“…As shown in Figure , in the sequence of reactions following formation of 1 P 680 *, without histidine electron transfer is highly unfavorable. Oxidation of tyrosine is too slow to compete with back electron transfer from Q A •– to P 680 •+ . ,, With His(190) in place and MS-EPT available, the energetics are favorable by ∼0.2 eV.…”

Section: Introductionmentioning

confidence: 99%

Proton-Coupled Electron Transfer

et al. 2012

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An initial review (PCET1) on proton-coupled electron transfer (PCET) by Huynh and Meyer appeared in Chemical Reviews in 2007. 1 This is a perennial review, a follow up on the original. It was intended for the special Chemical Reviews edition on Proton Coupled Electron Transfer that appeared in December, 2010 (Volume 110, Issue 12 Pages 6937-710). The reader is referred to it with articles on electrochemical approaches to studying PCET by Costentin and coworkers, 2 theory of electron proton transfer reactions by Hammes-Schiffer and coworkers, 3 proton-coupled electron flow in proteins and enzymes by Gray and coworkers, 4 and the thermochemistry of proton-coupled electron transfer by Mayer and coworkers. 5 Coverage for the current review is intended to be broad, covering all aspects of the topic comprehensively with literature coverage overlapping with the later references in PCET1 until late 2010. There is a growing understanding of the importance of PCET in chemistry and biology and its implications for catalysis and energy conversion. This has led to a series of informative reviews that have appeared since 2007. They include: "The possible role of Proton-coupled electron Transfer (PCET) in Water oxidation by Photosystem II" by Meyer and coworkers in 2007, 6 "Theoretical studies of proton-coupled electron transfer: Models and concepts relevant to bioenergetics" by Hammes-Schiffer and coworkers in 2008, 7 "Electrochemical Approach to the Mechanistic Study of Proton-Coupled Electron Transfer" by Costentin in 2008, 8 "Proton-Coupled Electron Transfer in Biology: Results from Synergistic Studies in Natural and Model Systems" by Nocera and Reece in 2009, 9 and "Integrating Proton-Coupled Electron Transfer and Excited States" by Meyer and coworkers in 2010. 10

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“…Manganese(II), being an integral part of Mn(II)-POR, plays a major role in different biological processes, most notably glutamine synthetase in astrocytes of the human brain. − Enzymes requiring manganese as a cofactor are typically large and include different classes of enzymes including oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases, lectins, and integrins. , Typical examples are reverse transcriptases of many retroviruses (though not lentiviruses such as HIV), arginases, − the diphtheria toxin, , and Mn-containing superoxide dismutase (Mn-SOD). ,, A number of experimental and theoretical studies were carried out to investigate manganese containing biomolecules. − Theoretical methods provided insights into Mn-containing molecules, but their applications are limited by the lack of adequate force-field parameters required for the evaluation of physiochemical properties (e.g., via molecular dynamics simulations). In many cases, the problem of missing force-field parameters for manganese-containing systems is resolved by simply utilizing the parameters of a magnesium ion instead because both share a similar coordination pattern.…”

Section: Introductionmentioning

confidence: 99%

Hydration of Closely Related Manganese and Magnesium Porphyrins in Aqueous Solutions: Ab Initio Quantum Mechanical Charge Field Molecular Dynamics Simulation Study

2019

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To the best of our knowledge, the current study based on ab initio quantum mechanical charge field molecular dynamics (QMCF-MD) is the first to explore the difference in the hydration behavior between Mn(II)-and Mg(II)-associated porphyrins (Mn(II)-POR and Mg(II)-POR) in aqueous solution. The simulation study highlights similar and dissimilar characteristics of the structural, dynamical, and thermodynamical properties of these closely related metals bound to porphyrins in aqueous solution. The structural analysis is based on radial and angular distribution functions, coordination number distributions, and angular-radial distributions. Both hydrated systems demonstrate similar pentacoordinated structures formed via the axial coordination of one water molecule to the metal ion in addition to the four nitrogen atoms of the porphyrin ring. However, in the case of Mn(II)-POR, the formation of a distorted square pyramidal geometry was observed. It was envisaged as a weak coordination of the water molecule to the Mn(II) atom and thus higher atomic fluctuation for all atoms in contrast to that for the hydrated Mg(II)-POR. The dynamical data in terms of the mean residence times, velocity autocorrelation function, free energy, and other parameters revealed the difference in the metal binding effect because the Mn(II) atom was observed to inhibit H-bond formation more than the presence of Mg(II) atoms in the core of the porphyrin. The current study thus highlights the significant differences in the structural and dynamical properties of Mn(II)-and Mg(II)associated porphyrin systems.

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Manganese Proteins with Mono‐ & Dinuclear Sites

Cited by 3 publications

References 28 publications

The Possible Role of Proton‐Coupled Electron Transfer (PCET) in Water Oxidation by Photosystem II

The Possible Role of Proton‐Coupled Electron Transfer (PCET) in Water Oxidation by Photosystem II

Proton-Coupled Electron Transfer

Hydration of Closely Related Manganese and Magnesium Porphyrins in Aqueous Solutions: Ab Initio Quantum Mechanical Charge Field Molecular Dynamics Simulation Study

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