ATP-induced electron transfer by redox-selective partner recognition

Hennig, Sandra E.; Goetzl, Sebastian; Jeoung, Jae‐Hun; Bommer, Martin; Lendzian, Friedhelm; Hildebrandt, Peter; Dobbek, Holger

doi:10.1038/ncomms5626

Cited by 21 publications

(48 citation statements)

References 33 publications

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“…In contrast, the binding of the activator RACo to its corrinoid substrate CoFeSP caused a markedly decrease of the midpoint potential of the [Co II ]/[Co I ] couple of CoFeSP. The potential changed from −450 mV (CoFeSP alone) to below −600 mV (+ RACo), resulting in a stabilization of the [Co II ] form . This might explain why the predicted function of ATP hydrolysis during corrinoid reduction differs between O ‐demethylases and CoFeSP.…”

Section: Resultssupporting

confidence: 62%

“…In O ‐demethylases, the midpoint potential of the corrinoid cofactor ([Co II ]/[Co I ]), which is the electron‐accepting site, is increased during activation from <−500 mV to about −300 mV allowing the electron flow from a low potential donor to the more positive [Co II ]–corrinoid cofactor . In nitrogenase and during activation of the corrinoid iron–sulfur protein (CoFeSP), the main function of ATP hydrolysis seems to be the dissociation of a protein complex composed of the activator and the electron‐accepting protein, which enables the unidirectional flow of electrons . How ATP binding and/or hydrolysis in combination with conformational changes of the participating proteins accomplish these tasks is still under investigation.…”

Section: Introductionmentioning

confidence: 99%

“…9,10 The monomeric activator of corrinoid-dependent methyltransferases (like O-demethylases or the methyltransferases of the Wood-Ljungdahl pathway) contains one [2Fe-2S] or two [4Fe-4S] clusters. 7,11,12 Although a few structures of the activators, either as single proteins or in complex with its protein substrate, were solved (e.g., [13][14][15][16][17] ), the mechanisms of ATP-dependent activation are not yet fully understood; however, they seem to differ among the enzymes. In benzoyl-CoA reductases and 2-hydroxyacyl-CoA dehydratases, the hydrolysis of ATP induces a decrease in the potential of the donated electrons from around −400 mV to ca.…”

Section: Introductionmentioning

confidence: 99%

“…3,7 In nitrogenase and during activation of the corrinoid iron-sulfur protein (CoFeSP), the main function of ATP hydrolysis seems to be the dissociation of a protein complex composed of the activator and the electron-accepting protein, which enables the unidirectional flow of electrons. 17,18 How ATP binding and/or hydrolysis in combination with conformational changes of the participating proteins accomplish these tasks is still under investigation.…”

Section: Introductionmentioning

confidence: 99%

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Redox potential changes during ATP‐dependent corrinoid reduction determined by redox titrations with europium(II)–DTPA

2019

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Corrinoids are essential cofactors of enzymes involved in the C1 metabolism of anaerobes. The active, super‐reduced [CoI] state of the corrinoid cofactor is highly sensitive to autoxidation. In O‐demethylases, the oxidation to inactive [CoII] is reversed by an ATP‐dependent electron transfer catalyzed by the activating enzyme (AE). The redox potential changes of the corrinoid cofactor, which occur during this reaction, were studied by potentiometric titration coupled to UV/visible spectroscopy. By applying europium(II)–diethylenetriaminepentaacetic acid (DTPA) as a reductant, we were able to determine the midpoint potential of the [CoII]/[CoI] couple of the protein‐bound corrinoid cofactor in the absence and presence of AE and/or ATP. The data revealed that the transfer of electrons from a physiological donor to the corrinoid as the electron‐accepting site is achieved by increasing the potential of the corrinoid cofactor from −530 ± 15 mV to −250 ± 10 mV (ESHE, pH 7.5). The first 50 to 100 mV of the shift of the redox potential seem to be caused by the interaction of nucleotide‐bound AE with the corrinoid protein or its cofactor. The remaining 150–200 mV had to be overcome by the chemical energy of ATP hydrolysis. The experiments revealed that Eu(II)–DTPA, which was already known as a powerful reducing agent, is a suitable electron donor for titration experiments of low‐potential redox centers. Furthermore, the results of this study will contribute to the understanding of thermodynamically unfavorable electron transfer processes driven by the power of ATP hydrolysis.

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Section: Resultssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Redox potential changes during ATP‐dependent corrinoid reduction determined by redox titrations with europium(II)–DTPA

2019

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“…As a precedent for such a mechanism, in the much more complex nitrogenases, ATP binding is required to promote electron transfer to N 2 (Duval et al, 2013). Similarly, ATP binding is required to drive electron transfer to B 12 -dependent methyl transferases for their activation (Hennig et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

Cellular Metabolites Enhance the Light Sensitivity of Arabidopsis Cryptochrome through Alternate Electron Transfer Pathways

et al. 2014

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Cryptochromes are blue light receptors with multiple signaling roles in plants and animals. Plant cryptochrome (cry1 and cry2) biological activity has been linked to flavin photoreduction via an electron transport chain comprising three evolutionarily conserved tryptophan residues known as the Trp triad. Recently, it has been reported that cry2 Trp triad mutants, which fail to undergo photoreduction in vitro, nonetheless show biological activity in vivo, raising the possibility of alternate signaling pathways. Here, we show that Arabidopsis thaliana cry2 proteins containing Trp triad mutations indeed undergo robust photoreduction in living cultured insect cells. UV/Vis and electron paramagnetic resonance spectroscopy resolves the discrepancy between in vivo and in vitro photochemical activity, as small metabolites, including NADPH, NADH, and ATP, were found to promote cry photoreduction even in mutants lacking the classic Trp triad electron transfer chain. These metabolites facilitate alternate electron transfer pathways and increase light-induced radical pair formation. We conclude that cryptochrome activation is consistent with a mechanism of light-induced electron transfer followed by flavin photoreduction in vivo. We further conclude that in vivo modulation by cellular compounds represents a feature of the cryptochrome signaling mechanism that has important consequences for light responsivity and activation.

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CODehydrogenase and Acetyl‐CoASynthase Assembly

Dobbek

2017

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Ni,Fe‐containing carbon monoxide dehydrogenases (CODHs) and acetyl‐CoA synthases (ACSs) are ubiquitous among anaerobic bacteria and archaea. CODHs catalyze the reversible reduction of CO 2 with two electrons and two protons to CO and water. ACSs catalyze the reversible condensation of CO, coenzyme A, and a methyl cation to acetyl‐CoA, and both enzymes can occur in a monofunctional or as a stable bifunctional complex. Compared to what is known about the maturation of other Ni‐containing enzymes, how CODH and ACS mature is just beginning to emerge. Despite differences in active‐site metal content (CODH: 1xNi, 4xFe; ACS: 2xNi, 4xFe), architecture (CODH: Ni integrated in a NiFe 3 S 4 cubanoidal subcluster; ACS: two Ni next to a [4Fe4S] cluster), active‐site accessibility, and protein fold, both Ni,Fe‐clusters are matured by homologous ATPases of the MinD/Mrp‐family called CooC (CODH maturation) and AcsF (ACS maturation). CooC sustains the ATP‐dependent Ni insertion into the active‐site cluster of CODHs in the presence of physiological nickel concentrations. CooC can bind nickel at a GCXC motif in the dimer interface and ADP/ATP binding changes the coordination of nickel. AcsF forms a tight complex with Ni‐free ACS, together creating a binding platform for two nickel ions. The Ni‐loaded ACS–AcsF complex remains inactive until MgATP is added to it, resulting in fully active ACS. Details of the mechanisms and structures known to date are discussed in the chapter.

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ATP-induced electron transfer by redox-selective partner recognition

Cited by 21 publications

References 33 publications

Redox potential changes during ATP‐dependent corrinoid reduction determined by redox titrations with europium(II)–DTPA

Redox potential changes during ATP‐dependent corrinoid reduction determined by redox titrations with europium(II)–DTPA

Cellular Metabolites Enhance the Light Sensitivity of Arabidopsis Cryptochrome through Alternate Electron Transfer Pathways

CODehydrogenase and Acetyl‐CoASynthase Assembly

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