Literature summary for 1.4.9.1 extracted from

Shin, S.; Davidson, V.L.
MauG, a diheme enzyme that catalyzes tryptophan tryptophylquinone biosynthesis by remote catalysis (2014), Arch. Biochem. Biophys., 544, 112-118 .

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Activating Compound

Activating Compound	Comment	Organism	Structure
amicyanin	-	Paracoccus denitrificans
MauG	pre-enzyme MADH and its activator MauG perform a distinct form of enzyme catalysis that requires multi-step hole hopping-mediated long range electron transfer, mechanism, overview. The distance between the modified residues of preMADH and the nearest heme iron of MauG is 19 A, which is still a relatively long distance for biological electron transfer. MauG behaves more like a b-type heme enzyme than a c-type heme enzyme. Residue Trp93 and the bound Ca2+ are also components of the diheme cofactor. Ca2+ is positioned in the vicinity of the two hemes and is connected to each heme via H-bonding networks that include bound waters. Ca2+-depleted MauG shows no TTQ biosynthesis activity and exhibits altered absorbance, EPR and resonance Raman spectral properties. Re-addition of Ca2+ fully restores activity and the native spectral properties. Residue Pro107 is critical in maintaining the properstructure of the distal heme pocket of the high-spin heme of MauG to allow oxygen to bind. Trp199 of MauG, which resides at the MauG-preMADH interface, is positioned midway between the residues on preMADH that are modified and the nearest heme. Kinetic mechanism of MauG-dependent TTQ biosynthesis, overview	Paracoccus denitrificans
additional information	the gene which encodes MauG is located in the methylamine utilization (mau) gene cluster of several gram negative bacteria. The mau cluster contains the two structural genes for MADH as well as accessory proteins that are required for MADH biogenesis	Paracoccus denitrificans

Cloned(Commentary)

Cloned (Comment)	Organism
MADH is a heterotetramer consisting of two alpha subunits and two beta subunits which are encoded by mauB and mauA, respectively	Paracoccus denitrificans

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
methylamine + H2O + 2 amicyanin	Paracoccus denitrificans	-	formaldehyde + NH3 + 2 reduced amicyanin	-	?

Organism

Organism	UniProt	Comment	Textmining
Paracoccus denitrificans	P22619 AND P29894	alpha and beta subunits encoded by genes mauA and mauB	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
methylamine + H2O + 2 amicyanin	-	Paracoccus denitrificans	formaldehyde + NH3 + 2 reduced amicyanin	-	?

Subunits

Subunits	Comment	Organism
heterotetramer	alpha2beta2	Paracoccus denitrificans
More	MADH is a heterotetramer consisting of two alpha subunits and two beta subunits which are encoded by mauB and mauA, respectively	Paracoccus denitrificans

Cofactor

Cofactor	Comment	Organism	Structure
tryptophan tryptophylquinone	TTQ, the catalytic cofactor of enzyme MADH. It is not an exogenous cofactor but is instead derived from posttranslational modifications of the beta subunits of MADH as evidenced from the crystal structure of MADH. Kinetic mechanism of MauG-dependent TTQ biosynthesis, overview	Paracoccus denitrificans

General Information

General Information	Comment	Organism
physiological function	MADH catalyzes the oxidative deamination of methylamine to formaldehyde and ammonia, a reaction which allows the host bacterium to use methylamine as a sole source of carbon, nitrogen and energy. MADH donates the electrons which it extracts from methylamine to the mauC gene product, a type 1 copper protein named amicyanin, which in turn transfers electrons to cytochrome c-551i. The catalytic cofactor of MADH is tryptophan tryptophyquinone, TTQ	Paracoccus denitrificans

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Release 2023.1 (January 2023)