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Title: Equilibrium and ultrafast kinetic studies manipulating electron transfer: A short-lived flavin semiquinone is not sufficient for electron bifurcation

Journal Article · · Journal of Biological Chemistry
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Flavin-based electron transfer bifurcation is emerging as a fundamental and powerful mechanism for conservation and deployment of electrochemical energy in enzymatic systems. In this process, a pair of electrons is acquired at intermediate reduction potential (i.e. intermediate reducing power) and each electron is passed to a different acceptor, one with lower and the other with higher reducing power, leading to 'bifurcation'. It is believed that a strongly reducing semiquinone species is essential for this process, and it is expected that this species should be kinetically short-lived. We now demonstrate that presence of a short-lived anionic flavin semiquinone (ASQ) is not sufficient to infer existence of bifurcating activity, although such a species may be necessary for the process. We have used transient absorption spectroscopy to compare the rates and mechanisms of decay of ASQ generated photochemically in bifurcating NADH-dependent ferredoxin-NADP+ oxidoreductase and the non-bifurcating flavoproteins nitroreductase, NADH oxidase and flavodoxin. We found that different mechanisms dominate ASQ decay in the different protein environments, producing lifetimes ranging over two orders of magnitude. Capacity for electron transfer among redox cofactors vs. charge recombination with nearby donors can explain the range of ASQ lifetimes we observe. In conclusion, our results support a model wherein efficient electron propagation can explain the short lifetime of the ASQ of bifurcating NADH-dependent ferredoxin-NADP+ oxidoreductase I, and can be an indication of capacity for electron bifurcation.

Research Organization:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
SC0012518; AC36–08-GO28308; AC36-08GO28308
OSTI ID:
1769200
Alternate ID(s):
OSTI ID: 1395083
Report Number(s):
NREL/JA-2700-68454; S0021925820342228; PII: S0021925820342228
Journal Information:
Journal of Biological Chemistry, Journal Name: Journal of Biological Chemistry Vol. 292 Journal Issue: 34; ISSN 0021-9258
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 17 works
Citation information provided by
Web of Science

References (48)

Flavin Thermodynamics Explain the Oxygen Insensitivity of Enteric Nitroreductases † journal December 2002
Insights into Flavin-based Electron Bifurcation via the NADH-dependent Reduced Ferredoxin:NADP Oxidoreductase Structure journal July 2015
Redox and flavin-binding properties of recombinant flavodoxin from Desulfovibrio vulgaris (Hildenborough) journal December 1991
Steady-state kinetic mechanism, stereospecificity, substrate and inhibitor specificity of Enterobacter cloacae nitroreductase journal September 1998
The fixABCX Genes in Rhodospirillum rubrum Encode a Putative Membrane Complex Participating in Electron Transfer to Nitrogenase journal March 2004
Azorhizobium caulinodans electron-transferring flavoprotein N electrochemically couples pyruvate dehydrogenase complex activity to N2 fixation journal January 2004
Mechanistic insights into energy conservation by flavin-based electron bifurcation journal April 2017
New Oxidation—Reduction Indicators. I. Phenylanthranilic Acid (o-Diphenylamine Carbonic Acid) journal June 1936
Site-Directed Mutagenesis of Tyrosine-98 in the Flavodoxin from Desulfovibrio vulgaris (Hildenborough): Regulation of Oxidation-Reduction Properties of the Bound FMN Cofactor by Aromatic, Solvent, and Electrostatic Interactions journal July 1994
Excited State Dynamics Can Be Used to Probe Donor-Acceptor Distances for H-Tunneling Reactions Catalyzed by Flavoproteins journal December 2013
Fluorescence quenching of flavins by reductive agents journal July 2007
Redox bifurcations: Mechanisms and importance to life now, and at its origin: A widespread means of energy conversion in biology unfolds… journal November 2011
Production of Hydrogen Gas from Light and the Inorganic Electron Donor Thiosulfate by Rhodopseudomonas palustris journal October 2010
The protonmotive Q cycle: A general formulation journal November 1975
Form Follows Function: Structural and Catalytic Variation in the Class A Flavoprotein Monooxygenases journal November 2012
Iron chelation and redox chemistry of anthranilic acid and 3-hydroxyanthranilic acid: A comparison of two structurally related kynurenine pathway metabolites to obtain improved insights into their potential role in neurological disease development journal April 2015
Energy conservation via electron bifurcating ferredoxin reduction and proton/Na+ translocating ferredoxin oxidation journal February 2013
Studies on the Mechanism of Electron Bifurcation Catalyzed by Electron Transferring Flavoprotein (Etf) and Butyryl-CoA Dehydrogenase (Bcd) of Acidaminococcus fermentans journal December 2013
Purification and Characterization of Flavodoxin from Peptostreptococcus elsdenii journal February 1969
Overexpression, Isotopic Labeling, and Spectral Characterization ofEnterobacter cloacaeNitroreductase journal June 1998
Excited State Structure and Dynamics of the Neutral and Anionic Flavin Radical Revealed by Ultrafast Transient Mid-IR to Visible Spectroscopy journal May 2012
Excited-State Dynamics of Fully Reduced Flavins and Flavoenzymes Studied at Subpicosecond Time Resolution journal August 1998
Electron Transfer in Proteins journal June 1996
Redox Modulation of Flavin and Tyrosine Determines Photoinduced Proton-coupled Electron Transfer and Photoactivation of BLUF Photoreceptors journal July 2012
Barrier Compression Enhances an Enzymatic Hydrogen-Transfer Reaction journal February 2009
Crystal structure of NADH oxidase from Thermus thermophilus journal December 1995
Comparison of the refined crystal structures of wild-type (1.34 Å) flavodoxin from Desulfovibrio vulgaris and the S35C mutant (1.44 Å) at 100 K journal September 2002
Femtosecond Fluorescence Dynamics of Flavoproteins:  Comparative Studies on Flavodoxin, Its Site-Directed Mutants, and Riboflavin Binding Protein Regarding Ultrafast Electron Transfer in Protein Nanospaces journal September 2002
On the universal core of bioenergetics journal February 2013
Electrochemical Behaviour of Benzoic Acid on Platinum and Gold Electrodes journal November 2003
Flavin-sensitized electrode system for oxygen evolution using photo-electrocatalysis journal January 2016
Oxidation of Benzoic Acid by Electrochemically Generated Ce(IV) journal August 2005
Interaction of phenols with old yellow enzyme. Physical evidence for charge-transfer complexes. journal September 1976
Ultrafast Fluorescence Relaxation Spectroscopy of 6,7-Dimethyl-(8-ribityl)-lumazine and Riboflavin, Free and Bound to Antenna Proteins from Bioluminescent Bacteria journal October 2003
Versatility and specificity in flavoenzymes: Control mechanisms of flavin reactivity journal January 2001
Understanding the Broad Substrate Repertoire of Nitroreductase Based on Its Kinetic Mechanism journal April 2014
On the Role of Aromatic Side Chains in the Photoactivation of BLUF Domains † journal June 2007
Multiple Time Scale Backbone Dynamics of Homologous Thermophilic and Mesophilic Ribonuclease HI Enzymes journal June 2004
The Application of the Quinhydrone Electrode to Electrometric Acid-Base Titrations in the Presence of air, and the Factors Limiting its use in Alkaline Solution journal September 1923
Determining complete electron flow in the cofactor photoreduction of oxidized photolyase journal July 2013
UCSF Chimera?A visualization system for exploratory research and analysis journal January 2004
Structures of Nitroreductase in Three States: EFFECTS OF INHIBITOR BINDING AND REDUCTION journal January 2002
Purification and characterization of a NADH oxidase from the thermophile Thermus thermophilus HB8 journal May 1992
Touchdown PCR for increased specificity and sensitivity in PCR amplification journal August 2008
Femtosecond Dynamics of Short-Range Protein Electron Transfer in Flavodoxin journal November 2013
Hydrogen-bond switching through a radical pair mechanism in a flavin-binding photoreceptor journal July 2006
Slaving: Solvent fluctuations dominate protein dynamics and functions journal November 2002
Electron bifurcation journal April 2016

Cited By (4)

Material descriptors for photocatalyst/catalyst design journal May 2018
Delocalized hole transport coupled to sub-ns tryptophanyl deprotonation promotes photoreduction of class II photolyases journal January 2018
Ultrafast photoinduced flavin dynamics in the unusual active site of the tRNA methyltransferase TrmFO journal January 2019
Flavin-Based Electron Bifurcation, Ferredoxin, Flavodoxin, and Anaerobic Respiration With Protons (Ech) or NAD+ (Rnf) as Electron Acceptors: A Historical Review journal March 2018

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Related Subjects

09 BIOMASS FUELS
electron transfer
energetics
flavin
flavoprotein
fluorescence
electron bifurcation
transient absorption spectrocopy