EC Number   |
Activating Compound |
Reference |
|---|
   1.4.9.1 | amicyanin |
- |
741759, 742302, 742527 |
| 1.4.9.1 | benzylamine |
activates sQH-AmDH |
702763 |
| 1.4.9.1 | Dithionite |
rapidly activates sQH-AmDH, activation process involves a reduction process |
702763 |
| 1.4.9.1 | dithiothreitol |
rapidly activates sQH-AmDH, activation process involves a reduction process |
702763 |
| 1.4.9.1 | MauG |
42 kDa activator enzyme of methylamine dehydrogenase, the MauG residue Gln103 is important for the redox properties and stability of MauG. The diheme enzyme MauG catalyzes a six electron oxidation that is required for the posttranslational modification of a precursor of methylamine dehydrogenase (preMADH) to complete the biosynthesis of its protein-derived cofactor, tryptophan tryptophylquinone (TTQ). The substrate for MauG that undergoes this posttranslational modification is a precursor protein of MADH (preMADH). It possesses a monohydroxylated residue betaTrp57. The reactions catalyzed by MauG occur in the following order: covalent cross-linking of monohydroxylated betaTrp57 to betaTrp108, incorporation of a second oxygen atom into the side chain of betaTrp57, and oxidation of the quinol species to the quinone. Catalysis requires long-range electron transfer because preMADH does not make direct contact with either heme of MauG. The electron transfer occurs via a hole-hopping mechanism in which Trp residues of MauG are reversibly oxidized. Steady-state kinetic parameters of the MauG-dependent biosynthesis of TTQ from preMADH, overview. Analysis of effects of the Q103 mutations on the visible absorption spectra of the diferric and diferrous redox states of MauG |
741893 |
| 1.4.9.1 | MauG |
a diheme enzyme, the diheme enzyme MauG catalyzes oxidative post-translational modifications of a protein substrate, precursor protein of methylamine dehydrogenase (preMADH), that binds to the surface of MauG. The high-spin heme iron of MauG is located 40A 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 heme 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. Substrate binding alters the environment in the distal heme pocket of the high-spin heme over very long distance. MauG structure, PDB ID 3L4M. Kinetics overview |
742527 |
| 1.4.9.1 | 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 |
741759 |
| 1.4.9.1 | MauG |
the di-heme enzyme is required for methylamine dehydrogenase maturation. MauG is highly unusual in that the di-ferrous c-type heme redox state can also bind and activate O2. Mixing preMADH with either di-ferric MauG and H2O2 or di-ferrous MauG and O2, leads to fully active MADH. Thus, MauG represents the final enzyme in MADH maturation, catalyzing a 6-electron oxidation to complete tryptophan tryptophyquinone, TTQ, biosynthesis. Upon reaction of di-ferric MauG with H2O2, an unprecedented high-valent species is formed, which Mossbauer spectroscopy showed contains both MauG hemes in the Fe(IV) oxidation state. Analysis of the crystal structure of MauG in complex with preMADH at 2.1 resolution, overview. MauG reaction mechanism and kinetics with preMADH and H2O2. MauG-dependent completion of TTQ biosynthesis requires a hole hopping electron transfer mechanism. Structure-function analysis. The MauG Y294H variant is unable to catalyze TTQ biosynthesis |
742338 |
| 1.4.9.1 | MauG |
the diheme enzyme MauG catalyses a six-electron oxidation required for post-translational modification of preMADH (precursor of methylamine dehydrogenase) to complete the biosynthesis of its tryptophan tryptophylquinone, TTQ, cofactor. mutation of Trp93 of MauG to tyrosine causes loss of bound Ca2+ and alters the kinetic mechanism of tryptophan tryptophylquinone cofactor biosynthesis, overview. Whereas Ca2+-depleted wild-type MauG is inactive, W93Y MauG exhibits TTQ biosynthesis activity, although with much lower rate and highly unusual kinetic behaviour. The steady-state reaction exhibits a long lag phase, the duration of which is dependent on the concentration of preMADH, kinetic modeling. Analysis of th structures of Trp93 and Ca2+ site in MauG |
741849 |
| 1.4.9.1 | MauG |
the inactive 119 kDa heterotetrameric precursor of MADH with incompletely synthesized tryptophan tryptophylquinone can be converted to active MADH with mature tryptophan tryptophylquinone in vitro by reaction with MauG, a 42 kDa diheme enzyme |
685218 |
