A flavoprotein (FAD). The enzyme, characterized from the bacterium Arthrobacter globiformis, contains two active sites connected by a large "reaction chamber". An imine intermediate is transferred between the sites, eliminating the production of toxic formaldehyde. In the absence of folate the enzyme does form formaldehyde. Does not oxidize sarcosine. cf. EC 1.5.8.4, dimethylglycine dehydrogenase.
The taxonomic range for the selected organisms is: Arthrobacter globiformis The expected taxonomic range for this enzyme is: Bacteria, Archaea, Eukaryota
reaction mechanism, substrate binding structures, bifunctional enzyme catalyzing the formation of 5,10-methylne tetrahydrofolate and the oxidation of N,N-dimethylglycine, active site structures, Tyr259 and His225 are involved in catalysis
tetrahydrofolate-binding site of enzyme is highly specific for reduced folate compounds and enhances the nucleophilic character of the tetrahydrofolate N10 position
A flavoprotein (FAD). The enzyme, characterized from the bacterium Arthrobacter globiformis, contains two active sites connected by a large "reaction chamber". An imine intermediate is transferred between the sites, eliminating the production of toxic formaldehyde. In the absence of folate the enzyme does form formaldehyde. Does not oxidize sarcosine. cf. EC 1.5.8.4, dimethylglycine dehydrogenase.
bifunctional enzyme catalyzing the formation of 5,10-methylene tetrahydrofolate and the oxidation of N,N-dimethylglycine, folate binding and active site, a large channel connects both active sites, the channeling is kinetically controlled by terahydrofolate binding, overview
the oxidation of dimethylglycine is coupled to the synthesis of 5,10-methylenetetrahydrofolate through an unusual substrate channeling mechanism. Uncoupling of the active sites can be achieved by mutagenesis or deletion of the 5,10-methylenetetrahydrofolate synthase site and this leads to accumulation of intracellular formaldehyde. Channeling occurs by nonbiased diffusion of the labile intermediate through a large solvent cavity connecting both active sites
In the absence of tetrahydrofolate, formaldehyde is the second product of catalysis, formed by hydrolysis of a labile iminium intermediate. In the cell, toxic formaldehyde is not produced and these enzymes catalyse the formation of 5,10-methylene-THF from THF and the labile iminium intermediate.
bifunctional enzyme catalyzing the formation of 5,10-methylene tetrahydrofolate and the oxidation of N,N-dimethylglycine, folate binding and active site, a large channel connects both active sites, the channeling is kinetically controlled by terahydrofolate binding, overview
the specific activity of DMGO decreased when cells are grown in the medium with high NaCl concentration. High osmolarity inhibits the activity of the enzyme, but not in the case of the medium with glycine betaine as the sole carbon source
in high-salinity media with 1 M NaCl, Arthrobacter globiformis accumulates 360 mM of glycine betaine when the main source of carbon is glucose and 180 mM glycine betaine when the sole carbon source is glycine betaine
purified recombinant wild-type enzyme, sitting-drop vapour diffusion method, 0.004 ml of protein solution containing 15 mg/ml protein, mixed with 0.002 ml reservoir solution containing 15% PEG 5000 monomethylether, 0.2 M MgCl2, and 0.1 M HEPES, pH 7.5, magnesium salt can be exchanged for acetate, for complexing the crystals are soaked in a solution containing folic or folinic acid in 15% PEG 5000 monomethylether and 0.3 M NaCl for 10 min, X-ray diffraction structure determination and analysis at 1.60 A resolution
complete removal of 5,10-CH2-THF synthase domain through expression of a truncated version generates a mutant enzyme unable to avoid hydrolysis of the imine species generated following amine oxidation
able to oxidize substrate, steady-state turnover is attenuated 200fold, rate of FAD reduction is substantially impaired, no stabilization of FADH2-iminium charge-transfer complex
Mechanism of FAD reduction and role of active site residues His-225 and Tyr-259 in Arthrobacter globiformis dimethylglycine oxidase: analysis of mutant structure and catalytic function