This is a bifunctional radical AdoMet (radical SAM) enzyme that catalyses the first two steps in the biosynthesis of the enzyme cofactor mycofactocin. Activity requires the presence of the MftB chaperone. The other activity of the enzyme is EC 4.1.99.26, 3-amino-5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidin-2-one synthase.
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The expected taxonomic range for this enzyme is: Mycobacteriaceae
This is a bifunctional radical AdoMet (radical SAM) enzyme that catalyses the first two steps in the biosynthesis of the enzyme cofactor mycofactocin. Activity requires the presence of the MftB chaperone. The other activity of the enzyme is EC 4.1.99.26, 3-amino-5-[(4-hydroxyphenyl)methyl]-4,4-dimethylpyrrolidin-2-one synthase.
enzyme additionally catalyzes SAM-dependent C-C bond formation between the Cbeta of the penultimate valine and the Calpha of the former tyrosine, forming a 3-amino-5-[(4-hydroxyphenyl) methyl]-4,4-dimethyl-2-pyrrolidinone moiety, i.e. MftA*, reaction of EC 4.1.99.26
enzyme additionally catalyzes SAM-dependent C-C bond formation between the Cbeta of the penultimate valine and the Calpha of the former tyrosine, forming a 3-amino-5-[(4-hydroxyphenyl) methyl]-4,4-dimethyl-2-pyrrolidinone moiety, i.e. MftA*, reaction of EC 4.1.99.26
MftC binds a radical S-adenosylmethionine [4Fe-4S] cluster and two auxiliary [4Fe-4S] clusters that are required for MftA modification. Presence of S-adenosylmethionine and MftA affects the environments of the radical S-adenosylmethionine and Aux I cluster whereas the Aux II cluster is unaffected by the substrates. All three cluster are required for cataylsis
a MftC deletion mutant is unable to grow in minimal medium containing cholesterol (0.01% [wt/vol]) as the sole carbon source with hot ethanol (1% [vol/vol]) as the solvent (cholesterol and EtOH [cholesterol:EtOH]). There is no significant growth retardation in cholesterol:DMSO. Supplementation of ethanol has no effect on mutant strain growth in propionate (0.5% [wt/vol]) or glycerol (0.2% [vol/vol]) but severely delays mutant strain growth in acetate (0.5% [wt/vol]) in comparison with the growth of the wild-type strain. MftC deletion results in multifold increases in expression of the DosR regulon genes in ethanol-treated strains
MtfC is a radical SAM enzyme and oxidatively decarboxylates the C-terminus of the MftA peptide in the presence of the accessory protein MftB. MftC abstracts a hydrogen atom from the beta-carbon of the C-terminal Tyr residue. The resulting radical species is stabilized by the adjacent phenol ring. Decarboxylation occurs either via transfer of the unpaired spin from the radical intermediate to a [4Fe-4S] cluster concomitant with decarboxylation to form the final product. Alternatively, the Calpha-COOH bond can be homolytically cleaved resulting in the formation of a COOH radical species that can either be quenched to formate or CO2
a MftC deletion mutant is unable to grow in minimal medium containing cholesterol (0.01% [wt/vol]) as the sole carbon source with hot ethanol (1% [vol/vol]) as the solvent (cholesterol and EtOH [cholesterol:EtOH]). There is no significant growth retardation in cholesterol:DMSO. Supplementation of ethanol has no effect on mutant strain growth in propionate (0.5% [wt/vol]) or glycerol (0.2% [vol/vol]) but severely delays mutant strain growth in acetate (0.5% [wt/vol]) in comparison with the growth of the wild-type strain. MftC deletion results in multifold increases in expression of the DosR regulon genes in ethanol-treated strains
MtfC is a radical SAM enzyme and oxidatively decarboxylates the C-terminus of the MftA peptide in the presence of the accessory protein MftB. MftC abstracts a hydrogen atom from the beta-carbon of the C-terminal Tyr residue. The resulting radical species is stabilized by the adjacent phenol ring. Decarboxylation occurs either via transfer of the unpaired spin from the radical intermediate to a [4Fe-4S] cluster concomitant with decarboxylation to form the final product. Alternatively, the Calpha-COOH bond can be homolytically cleaved resulting in the formation of a COOH radical species that can either be quenched to formate or CO2
auxiliary [4Fe-4S] cluster I mutant, capable of catalyzing the reductive cleavage of SAM to form dAdo but incapable of converting MftA to MftA* or MftA**
auxiliary [4Fe-4S] cluster II mutant, capable of catalyzing the reductive cleavage of SAM to form dAdo, incapable of converting MftA to MftA* or MftA**
systematical replacement of Cys residues by Ala. The RS KO could neither cleave SAM nor modify MftA, consistent with the successful knockout of the RS cluster. Activity assays for Aux I and Aux II KO's also provided insightful results. Both Aux I and Aux II KO's were capable of catalyzing the reductive cleavage of SAM to form dAdo (Figure 3A), suggesting that the RS cluster remained intact and in an active conformation in the mutated proteins. However, when assayed against MftA, both Aux I and Aux II KO's were incapable of converting MftA to MftA* or MftA**
Bioinformatic evidence for a widely distributed, ribosomally produced electron carrier precursor, its maturation proteins, and its nicotinoprotein redox partners