Tuning Catalytic Bias of Hydrogen Gas Producing Hydrogenases

Artz, Jacob H.; Zadvornyy, Oleg A.; Mulder, David W.; Keable, S.M.; Cohen, Aina E.; Ratzloff, Michael W.; Williams, S. Garrett; Ginovska, Bojana; Kumar, Neeraj; Song, Jianguo; McPhillips, S.E.; Davidson, Christine M.; Lyubimov, A.Y.; Pence, Natasha; Schut, Gerrit J.; Jones, Anne K.; Soltis, S. Michael; Adams, Michael W. W.; Raugei, Simone; King, Paul W.; Peters, John W.

doi:10.1021/jacs.9b08756

Cited by 59 publications

(120 citation statements)

References 46 publications

(80 reference statements)

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“…Here, the difference between Fe(II)-Fe(I) in Hox and Fe(I)-Fe(I) in Hsred is ~50 cm -1 29. It should be mentioned that a similar low frequency peak has been assigned to Hox in CpII 47. Infrared signature of Hox for different Group A [FeFe]-hydrogenases.…”

mentioning

confidence: 67%

“…At the [4Fe-4S] cluster, amino acid exchanges 45 and protonation differences 46 have been shown to affect the electrochemical properties of the H-cluster, and a similar effect was discussed for the orientation of a conserved serine (S2 in Figure 4). 47 Finally, a methionine residue below the Hcluster was suggested to promote the release of µCO into a semi-bridging or terminal position upon reduction of the diiron site (M1 in Figure 4). 29 The conservation of this methionine is a key difference between groups A/B and C/D and has important implications for the catalytic mechanism (Chapter 4).…”

Section: The Influence Of F-clusters and Protein Environmentmentioning

confidence: 99%

“…[122][123][124] This is in agreement with a recent study by Artz et al comparing cryogenic CpI crystal structures solved with both synchrotron radiation and the free electron laser (XFEL) light source at Stanford. 47 The authors were able to quantify the extent of photoreduction suggesting that in the presence of strong reductant up to 50% of CpI was found in a "more reduced conformation" featuring the H-cluster in a µCO geometry. The influence of temperature is discussed in the next chapter.…”

Section: Biophysical Investigations In Cristallomentioning

confidence: 99%

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New Approaches to an Old Problem: Original Techniques in [FeFe]-hydrogenase Research

Land¹,

Senger²,

Berggren³

et al. 2020

Preprint

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Even 20 years after the first crystal structures of [FeFe]-hydrogenase have been published, several aspects of biological hydrogen turnover are heatedly discussed. In this perspective, we give an overview on how the diversity of naturally occurring and artificially prepared, semi-synthetic [FeFe]-hydrogenases deepens our understanding of hydrogenase chemistry. In parallel, we cover new results from biophysical techniques that go beyond the scope of conventional electrochemistry, X-ray diffraction, EPR, and FTIR spectroscopy. Taking into account both proton transfer and electron transfer as well as the notorious sensitivity of [FeFe]-hydrogenases towards carbon monoxide, the discussion further touches upon the molecular proceedings of biological hydrogen turnover.

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mentioning

confidence: 67%

Section: The Influence Of F-clusters and Protein Environmentmentioning

confidence: 99%

Section: Biophysical Investigations In Cristallomentioning

confidence: 99%

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New Approaches to an Old Problem: Original Techniques in [FeFe]-hydrogenase Research

Land¹,

Senger²,

Berggren³

et al. 2020

Preprint

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“…7,8 Transition metals are critical to biological energy transformation reactions and are found in many enzyme active sites, including the FeMo cofactor in nitrogenase, leading to reduction of dinitrogen to ammonia, 9 the tungsten-or molybdenum-containing formate dehydrogenases, which reversibly reduce CO 2 to formate, 10 methyl coenzyme reductase, 11 which catalyzes the reduction of CH 3 -S-CoM to methane, and hydrogenases, which catalyze reversible H 2 activation chemistry. 12,13 For the latter, striking differences in preferences for H 2 oxidation or H 2 production reactivity for a series of three unique [FeFe]hydrogenases from Clostridium pasteurianum has been shown. 12,14 Each [FeFe]-hydrogenase incorporates a organometallic, iron-sulfur rich H cluster ( Fig.…”

Section: Introductionmentioning

confidence: 99%

“…12,13 For the latter, striking differences in preferences for H 2 oxidation or H 2 production reactivity for a series of three unique [FeFe]hydrogenases from Clostridium pasteurianum has been shown. 12,14 Each [FeFe]-hydrogenase incorporates a organometallic, iron-sulfur rich H cluster ( Fig. 1), with additional iron-sulfur clusters, or F clusters, that can provide electron transfer functions.…”

Section: Introductionmentioning

confidence: 99%

The Hydricity and Reactivity Relationship in [ FeFe ]-hydrogenases

Artz¹,

Mulder²,

Ratzloff³

et al. 2020

Preprint

Self Cite

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Reactivity of transition metal catalysts is controlled by covalent and non-covalent interactions that tune thermodynamic properties including hydricity. Hydricity is critical to catalytic activity and for modulating the reduction or oxidation of chemical compounds. Likewise, enzymes can employ transition metal cofactors and use metal-hydride intermediates tuned by protein frameworks to selectively control reactivity. One example, the [FeFe]-hydrogenases, catalyze reversible H2 activation with H2 oxidation to H+ reduction ratios spanning ~107 in rate, offering a model to determine the extent that hydricity controls reactivity. To address this question, the hydricity of the catalytic H cluster of two [FeFe]-hydrogenases, CpI and CpII, were compared. We show that for CpI, the higher rates of H+ reduction correspond to a more hydridic H cluster, whereas CpII, which strongly favors H2 oxidation, has a less hydridic H cluster. The results demonstrate that enzymes manipulate metal cofactor hydricity to enable an extraordinary range of chemical reactivity.

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Catalytic Bias in Enzymatic Metal Cofactor‐Based Oxidation–Reduction Catalysis

Varghese¹,

Mulder²,

Raugei³

et al. 2021

Encyclopedia of Inorganic and Bioinorganic Chemistry

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Catalytic bias refers to the relative rate preference of a catalyst for either the forward or reverse direction. In enzymatic metal cofactor‐based oxidation–reduction catalysis, the tuning of catalytic bias plays an underlying role in controlling rates of reactivity. For this, enzymes have evolved complex active sites that can exist in multiple oxidation states with differing reduction potentials in order to achieve challenging multi‐step, oxidation–reduction reactions. Conceivably, the relative stability of the intermediates that contribute to determining the rate‐limiting step of the catalytic cycle could impose catalytic bias, although mechanisms for this concept are just beginning to be realized. As one example, recent work on Clostridium pasteurianum [FeFe]‐hydrogenases which catalyze reversible hydrogen oxidation have shown that the differential stabilization/destabilization of active site oxidation states through either static or dynamic protein interactions can preferentially promote either the hydrogen oxidation or proton reduction direction of the reaction. This revealed how an enzymatic cofactor can impose bias in oxidation–reduction catalysis through various tuning mechanisms by protein scaffold interactions. The hypothesis based on achieving catalytic bias through the modulation of cofactor oxidation states critical for the reaction cycle can be extended more generally to other cofactor‐based oxidation–reductions catalysts. The current understanding of catalytic bias has significant implications for the design of synthetic catalysts used in industrial settings, as well as providing a greater fundamental understanding of the factors that control metabolic processes in all life.

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Tuning Catalytic Bias of Hydrogen Gas Producing Hydrogenases

Cited by 59 publications

References 46 publications

New Approaches to an Old Problem: Original Techniques in [FeFe]-hydrogenase Research

New Approaches to an Old Problem: Original Techniques in [FeFe]-hydrogenase Research

The Hydricity and Reactivity Relationship in [ FeFe ]-hydrogenases

Catalytic Bias in Enzymatic Metal Cofactor‐Based Oxidation–Reduction Catalysis

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