Complete Charge Regulation by a Redox Enzyme Upon Single Electron Transfer

Zhang, Ao Yun; Koone, Jordan C.; Dashnaw, Chad M.; Zahler, Collin T.; Shaw, Bryan F.

doi:10.1002/anie.202001452

Cited by 4 publications

(15 citation statements)

References 41 publications

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“…This can lead to fractional numbers of protons being transferred with the transfer of an integer number of electrons. This is exemplified by the metalloprotein charge ladders investigated by Shaw and co-workers. − These charge ladders connect the change in charge of an entire protein (Δ Z ) with redox change at the active site. In small metalloproteins such as azurin, cytochrome c , and myoglobin, a one-electron transfer event at the embedded metal ion induces changes in Δ Z that are not equal to 1.…”

Section: Insights and Emerging Areas Of Pcet Thermochemistrymentioning

confidence: 99%

“…The level of charge regulation upon ET is associated with p K a changes, and thus protonation state changes, at amino acids both near and far from the metal ion via thermodynamic coupling (Section ). In the case of copper–zinc superoxide dismutase, charge regulation is nearly perfect (Δ Z ≅ 0), which was attributed to proton transfer at the active site . Related information can be obtained from the pH dependence of the active site reduction potential.…”

Section: Insights and Emerging Areas Of Pcet Thermochemistrymentioning

confidence: 99%

“…In the case of copper−zinc superoxide dismutase, charge regulation is nearly perfect (ΔZ ≅ 0), which was attributed to proton transfer at the active site. 209 Related information can be obtained from the pH dependence of the active site reduction potential. From a biological PCET perspective, we hope that these types of measurement become more common.…”

Section: Selected Biological Systemsmentioning

confidence: 99%

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Free Energies of Proton-Coupled Electron Transfer Reagents and Their Applications

et al. 2021

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We present an update and revision to our 2010 review on the topic of protoncoupled electron transfer (PCET) reagent thermochemistry. Over the past decade, the data and thermochemical formalisms presented in that review have been of value to multiple fields. Concurrently, there have been advances in the thermochemical cycles and experimental methods used to measure these values. This Review (i) summarizes those advancements, (ii) corrects systematic errors in our prior review that shifted many of the absolute values in the tabulated data, (iii) provides updated tables of thermochemical values, and (iv) discusses new conclusions and opportunities from the assembled data and associated techniques. We advocate for updated thermochemical cycles that provide greater clarity and reduce experimental barriers to the calculation and measurement of Gibbs free energies for the conversion of X to XH n in PCET reactions. In particular, we demonstrate the utility and generality of reporting potentials of hydrogenation, E°(V vs H 2 ), in almost any solvent and how these values are connected to more widely reported bond dissociation free energies (BDFEs). The tabulated data demonstrate that E°(V vs H 2 ) and BDFEs are generally insensitive to the nature of the solvent and, in some cases, even to the phase (gas versus solution). This Review also presents introductions to several emerging fields in PCET thermochemistry to give readers windows into the diversity of research being performed. Some of the next frontiers in this rapidly growing field are coordination-induced bond weakening, PCET in novel solvent environments, and reactions at material interfaces.

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Section: Insights and Emerging Areas Of Pcet Thermochemistrymentioning

confidence: 99%

Section: Insights and Emerging Areas Of Pcet Thermochemistrymentioning

confidence: 99%

Section: Selected Biological Systemsmentioning

confidence: 99%

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Free Energies of Proton-Coupled Electron Transfer Reagents and Their Applications

et al. 2021

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“…We mixed properly metalated bovine 2Cu, 2Zn-SOD1 (bSOD1) that was isolated from cow erythrocytes with human 2Cu, 2Zn-SOD1 (hSOD1) isolated from human erythrocytes. These two proteins differ in their formal net charge by approximately 2 units (hSOD1 Z CE = −14.26/dimer, bSOD1 Z CE = −12.10/dimer) ( 50 ) and have similar mass. Both proteins were purchased from Sigma-Aldrich and used without further purification.…”

Section: Resultsmentioning

confidence: 99%

“…These two proteins are known to be properly metalated, fully, with two equivalents of copper and zinc in each subunit. Each protein also possesses a small satellite peak during CE, due to the deamidation of a single asparagine residue (N26) ( 50 ). Surprisingly, after 14 days, no heterodimer peak emerged, suggesting that bSOD1 and hSOD1 do not heterodimerize with each other ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Metal migration and subunit swapping in ALS-linked SOD1: Zn2+ transfer between mutant and wild-type occurs faster than the rate of heterodimerization

Dashnaw

Zhang²,

Gonzalez³

et al. 2022

Journal of Biological Chemistry

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Measuring how two proteins affect each other's net charge in a crowded environment

et al. 2021

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Theory predicts that the net charge (Z) of a protein can be altered by the net charge of a neighboring protein as the two approach one another below the Debye length. This type of charge regulation suggests that a protein's charge and perhaps function might be affected by neighboring proteins without direct binding. Charge regulation during protein crowding has never been directly measured due to analytical challenges. Here, we show that lysine specific protein crosslinkers (NHS ester-Staudinger pairs) can be used to mimic crowding by linking two non-interacting proteins at a maximal distance of $7.9 Å. The net charge of the regioisomeric dimers and preceding monomers can then be determined with lysine-acyl "protein charge ladders" and capillary electrophoresis. As a proof of concept, we covalently linked myoglobin (Z monomer = À0.43 ± 0.01) and α-lactalbumin (Z monomer = À4.63 ± 0.05). Amide hydrogen/deuterium exchange and circular dichroism spectroscopy demonstrated that crosslinking did not significantly alter the structure of either protein or result in direct binding (thus mimicking crowding). Ultimately, capillary electrophoretic analysis of the dimeric charge ladder detected a change in charge of ΔZ = À0.04 ± 0.09 upon crowding by this pair (Z dimer = À5.10 ± 0.07). These small values of ΔZ are not necessarily general to protein crowding (qualitatively or quantitatively) but will vary per protein size, charge, and solvent conditions.

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Complete Charge Regulation by a Redox Enzyme Upon Single Electron Transfer

Abstract: This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record.

Cited by 4 publications

References 41 publications

Free Energies of Proton-Coupled Electron Transfer Reagents and Their Applications

Free Energies of Proton-Coupled Electron Transfer Reagents and Their Applications

Metal migration and subunit swapping in ALS-linked SOD1: Zn2+ transfer between mutant and wild-type occurs faster than the rate of heterodimerization

Measuring how two proteins affect each other's net charge in a crowded environment

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