In Crystallo Posttranslational Modification Within a MauG/Pre–Methylamine Dehydrogenase Complex

Jensen, L.M.R.; Sanishvili, Ruslan; Davidson, Victor L.; Wilmot, Carrie M.

doi:10.1126/science.1182492

Cited by 112 publications

(272 citation statements)

References 20 publications

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“…3F). Tyr294 is one of the axial ligands of Heme 6C (10). In Y294H MauG, Heme 6C has an axial bis-histidine coordination, and the bis-Fe(IV) intermediate is not generated (16).…”

Section: Resultsmentioning

confidence: 99%

“…The HARLEM program (see Methods) was used to calculate H AB and β values for ET reactions in MauG using its crystal structure (10). These values were calculated for the single-step electron tunneling pathway between the hemes and the electron tunneling segments between Trp93 and each heme, the latter of which are parts of the proposed hopping mechanism for CR stabilization of bis-Fe(IV) MauG.…”

Section: Resultsmentioning

confidence: 99%

“…The optical spectra of MauG were recorded aerobically on a Cary 5000 UV-Vis-NIR spectrophotometer at room temperature in 50 mM potassium phosphate buffer, pH 7.5. between the two hemes of MauG based on the crystal structure (10). The ET parameters, including the decay constants (β) and the relative values of electronic coupling element (H AB ), for the single-step tunneling mechanism and the two-step Trp93-mediated hopping mechanism were calculated using the direct distance approach of Dutton and coworkers (42).…”

Section: Methodsmentioning

confidence: 99%

“…MauG uses two c-type hemes for oxidative posttranslational modifications of a precursor protein, preMADH, to generate TTQ (10). Spectroscopic and structural studies of MauG revealed the presence of a five-coordinate, high-spin heme with an axial histidine coordination (denoted as Heme 5C ) and a six-coordinate, low-spin heme with an unusual axial histidine-tyrosine coordination (denoted as Heme 6C ) in the resting diferric state (Fig.…”

mentioning

confidence: 99%

“…Spectroscopic and structural studies of MauG revealed the presence of a five-coordinate, high-spin heme with an axial histidine coordination (denoted as Heme 5C ) and a six-coordinate, low-spin heme with an unusual axial histidine-tyrosine coordination (denoted as Heme 6C ) in the resting diferric state (Fig. 1A) (10,11). The two Fe ions in MauG are separated by 21.1 Å, with the closest distance between the porphyrin rings being 14.5 Å (10).…”

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confidence: 99%

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Tryptophan-mediated charge-resonance stabilization in the bis -Fe(IV) redox state of MauG

Geng

Dornevil

Davidson

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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102

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The diheme enzyme MauG catalyzes posttranslational modifications of a methylamine dehydrogenase precursor protein to generate a tryptophan tryptophylquinone cofactor. The MauG-catalyzed reaction proceeds via a bis -Fe(IV) intermediate in which one heme is present as Fe(IV)=O and the other as Fe(IV) with axial histidine and tyrosine ligation. Herein, a unique near-infrared absorption feature exhibited specifically in bis -Fe(IV) MauG is described, and evidence is presented that it results from a charge-resonance-transition phenomenon. As the two hemes are physically separated by 14.5 Å, a hole-hopping mechanism is proposed in which a tryptophan residue located between the hemes is reversibly oxidized and reduced to increase the effective electronic coupling element and enhance the rate of reversible electron transfer between the hemes in bis -Fe(IV) MauG. Analysis of the MauG structure reveals that electron transfer via this mechanism is rapid enough to enable a charge-resonance stabilization of the bis -Fe(IV) state without direct contact between the hemes. The finding of the charge-resonance-transition phenomenon explains why the bis -Fe(IV) intermediate is stabilized in MauG and does not permanently oxidize its own aromatic residues.

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“…3F). Tyr294 is one of the axial ligands of Heme 6C (10). In Y294H MauG, Heme 6C has an axial bis-histidine coordination, and the bis-Fe(IV) intermediate is not generated (16).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Tryptophan-mediated charge-resonance stabilization in the bis -Fe(IV) redox state of MauG

Geng

Dornevil

Davidson

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

102

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Properties of the high‐spin heme of MauG are altered by binding of preMADH at the protein surface 40 Å away

Feng

Crudup

et al. 2017

FEBS Letters

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The diheme enzyme MauG catalyzes oxidative posttranslational modifications of a protein substrate, preMADH, that binds to the surface of MauG. The high-spin heme iron of MauG is located 40 Å from preMADH. The ferric heme is an equilibrium of five- and six-coordinate states. PreMADH binding increases the proportion of five-coordinate heme three-fold. On reaction of MauG with H2O2 both hemes become FeIV. In the absence of preMADH the hemes autoreduce to ferric in a multistep process involving multiple electron and proton transfers. Binding of preMADH in the absence of catalysis alters the mechanism of autoreduction of the ferryl heme. Thus, substrate binding alters the environment in the distal heme pocket of the high-spin heme over very long distance.

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Protein‐Derived Cofactors

Davidson

2014

Encyclopedia of Life Sciences

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Protein‐derived cofactors are catalytic or redox‐active centres in proteins that are formed by covalent irreversible posttranslational modification of one or more amino acid residues. The mechanisms by which these posttranslational modifications are catalysed are quite diverse. In some cases, these modifications occur autocatalytically, and in other cases, they are enzyme catalysed. The formation of protein‐derived cofactors expands the range of chemical reactions that may be catalysed by enzymes in the absence of exogenous metal or organic cofactors. Protein‐derived cofactors typically function as electrophiles in catalysis and sometimes stabilise free‐radical intermediates or mediate biological electron transfer. This article describes the structures and functions of several protein‐derived cofactors and the diverse mechanisms of posttranslational modification through which they are generated. Key Concepts: Protein‐derived cofactors are formed by irreversible posttranslational modification of amino acid residues. Protein‐derived cofactors typically serve as electrophiles or stabilise free radicals during enzyme catalysis. Amino acid residues may acquire new catalytic or redox functions from posttranslational modification. Modification of amino acids that provide ligands for metals can alter the properties of metalloenzymes. Protein‐derived cofactors may be formed by a variety of autocatalytic and enzyme‐catalysed processes.

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In Crystallo Posttranslational Modification Within a MauG/Pre–Methylamine Dehydrogenase Complex

Cited by 112 publications

References 20 publications

Tryptophan-mediated charge-resonance stabilization in the bis -Fe(IV) redox state of MauG

Tryptophan-mediated charge-resonance stabilization in the bis -Fe(IV) redox state of MauG

Properties of the high‐spin heme of MauG are altered by binding of preMADH at the protein surface 40 Å away

Protein‐Derived Cofactors

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