Unusual reactivity of a flavin in a bifurcating electron-transferring flavoprotein leads to flavin modification and a charge-transfer complex

Mohamed-Raseek, Nishya; Galen, Cornelius van; Stanley, Robert J.; Miller, Anne‐Frances

doi:10.1016/j.jbc.2022.102606

Cited by 3 publications

(8 citation statements)

References 92 publications

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“…Flavin released from WT-ETF additionally displayed a small long-wavelength shoulder near 530 nm, which has been assigned to 8 amino avin. 32,55 Thus, replacement of H290 by a non-H-bonding side chain not only destabilizes ET ASQ , but also impedes avin modication, consistent with anionic character shared between intermediate(s) in avin modication and the ASQ state.…”

Section: Suppression Of Et-avin Modication Upon Replacement Of H290...mentioning

confidence: 74%

“…This too is consistent with the proposed modication via methide (see Raseek et al and its ESI †). 32 However, unlike the WT, the variant H290F Y279I did not develop any signicant spectral changes over two weeks.…”

Section: Data Availabilitymentioning

confidence: 91%

“…Thus, it appears that the ET-FAD of WT-AfeETF is prone to conversion to 8fF ASQ at pH 7.0, as also documented for the Bf ETF from R. palustris at pH 9. 32 In contrast, the optical spectrum of H290F Y279I -ETF lacked the signatures of both 8fF and its spontaneous reduction to ASQ, and the spectrum of released FAD resembled that of authentic FAD instead. Both distinctions conrm the absence of avin modication in H290F Y279I -ETF.…”

Section: Flavins In H290f Y279i Etf Lack the Modication Found In Wt-etfmentioning

confidence: 94%

“…We sought to maximize modication by long incubation at pH 9.0 since the proposed iminoquinone methide intermediate should be favoured at high pH. 32,33,[35][36][37]53 Indeed, the spectral features acquired by WT ETF at pH 9.0 are attributable to 8fF while the variant retains the characteristic spectral features of FAD. The avins released from WT-ETF aer two weeks included 8fF, but avins released from H290F Y279I did not, as conrmed by UV-vis spectrometry (Fig.…”

Section: Data Availabilitymentioning

confidence: 99%

“…Another intriguing anomaly of the ET-FAD is its unusual propensity for chemical modification. 29–31 The proposed mechanisms of modification invoke deprotonation of the C8 methyl (C8m) or nucleophilic attack at C6 and a paraquinone methide-type transition state (reviewed in the ESI† of Mohamed Raseek, 32 and see ref. 23 and 33–36).…”

Section: Introductionmentioning

confidence: 99%

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A single hydrogen bond that tunes flavin redox reactivity and activates it for modification

Das,

Miller

2024

Chem. Sci.

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Section: Suppression Of Et-avin Modication Upon Replacement Of H290...mentioning

confidence: 74%

Section: Data Availabilitymentioning

confidence: 91%

Section: Flavins In H290f Y279i Etf Lack the Modication Found In Wt-etfmentioning

confidence: 94%

Section: Data Availabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A single hydrogen bond that tunes flavin redox reactivity and activates it for modification

Das,

Miller

2024

Chem. Sci.

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New Electron-Transfer Chain to a Flavodiiron Protein in Fusobacterium nucleatum Couples Butyryl-CoA Oxidation to O₂ Reduction

Bystrom,

Wolthers

2024

Biochemistry

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Fusobacterium nucleatum, a Gram-negative obligate anaerobe, is common to the oral microbiota, but the species is known to infect other sites of the body where it is associated with a range of pathologies. At present, little is known about the mechanisms by which F. nucleatum mitigates against oxidative and nitrosative stress. Inspection of the F. nucleatum subsp. polymorphum ATCC 10953 genome reveals that it encodes a flavodiiron protein (FDP; FNP2073) that is known in other organisms to reduce NO to N 2 O and/or O 2 to H 2 O. FNP2073 is dicistronic with a gene encoding a multicomponent enzyme termed BCR for butyryl-CoA reductase. BCR is composed of a butyryl-CoA dehydrogenase domain (BCD), the C-terminal domain of the α-subunit of the electron-transfer flavoprotein (Etfα), and a rubredoxin domain. We show that BCR and the FDP form an α 4 β 4 heterotetramic complex and use butyryl-CoA to selectively reduce O 2 to H 2 O. The FAD associated with the Etfα domain (α-FAD) forms red anionic semiquinone (FAD •− ), whereas the FAD present in the BCD domain (δ-FAD) forms the blue-neutral semiquinone (FADH • ), indicating that both cofactors participate in one-electron transfers. This was confirmed in stopped-flow studies where the reduction of oxidized BCR with an excess of butyryl-CoA resulted in rapid (<1.6 ms) interflavin electron transfer evidenced by the formation of the FAD •− . Analysis of bacterial genomes revealed that the dicistron is present in obligate anaerobic gut bacteria considered to be beneficial by virtue of their ability to produce butyrate. Thus, BCR-FDP may help to maintain anaerobiosis in the colon.

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Extended conformations of bifurcating electron transfer flavoprotein constitute up to half the population, possibly mediating conformational change

Khan,

Hicks,

Leite

et al. 2024

Chem. Sci.

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Unusual reactivity of a flavin in a bifurcating electron-transferring flavoprotein leads to flavin modification and a charge-transfer complex

Cited by 3 publications

References 92 publications

A single hydrogen bond that tunes flavin redox reactivity and activates it for modification

A single hydrogen bond that tunes flavin redox reactivity and activates it for modification

New Electron-Transfer Chain to a Flavodiiron Protein in Fusobacterium nucleatum Couples Butyryl-CoA Oxidation to O₂ Reduction

Extended conformations of bifurcating electron transfer flavoprotein constitute up to half the population, possibly mediating conformational change

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Unusual reactivity of a flavin in a bifurcating electron-transferring flavoprotein leads to flavin modification and a charge-transfer complex

Cited by 3 publications

References 92 publications

A single hydrogen bond that tunes flavin redox reactivity and activates it for modification

A single hydrogen bond that tunes flavin redox reactivity and activates it for modification

New Electron-Transfer Chain to a Flavodiiron Protein in Fusobacterium nucleatum Couples Butyryl-CoA Oxidation to O2 Reduction

Extended conformations of bifurcating electron transfer flavoprotein constitute up to half the population, possibly mediating conformational change

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Product

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About

New Electron-Transfer Chain to a Flavodiiron Protein in Fusobacterium nucleatum Couples Butyryl-CoA Oxidation to O₂ Reduction