3GSI

Crystal structure of D552A dimethylglycine oxidase mutant of Arthrobacter globiformis in complex with tetrahydrofolate

Summary for 3GSI

• Entry DOI: 10.2210/pdb3gsi/pdb
• Related: 1PJ5 1PJ6 1PJ7
• Descriptor: N,N-dimethylglycine oxidase, (6S)-5,6,7,8-TETRAHYDROFOLATE, MAGNESIUM ION, ... (5 entities in total)
• Functional Keywords: oxidoreductase, channelling, fad binding, folinic acid, folate binding, amine oxidation
• Biological source: Arthrobacter globiformis
• Total number of polymer chains: 1
• Total formula weight: 90997.41

Authors

Tralau, T.,Lafite, P.,Levy, C.,Combe, J.P.,Scrutton, N.S.,Leys, D. (deposition date: 2009-03-27, release date: 2009-04-14, Last modification date: 2024-02-21)

Primary citation

Tralau, T.,Lafite, P.,Levy, C.,Combe, J.P.,Scrutton, N.S.,Leys, D.
An internal reaction chamber in dimethylglycine oxidase provides efficient protection from exposure to toxic formaldehyde.
J.Biol.Chem., 284:17826-17834, 2009

PubMed Abstract: We report a synthetic biology approach to demonstrate substrate channeling in an unusual bifunctional flavoprotein dimethylglycine oxidase. The catabolism of dimethylglycine through methyl group oxidation can potentially liberate toxic formaldehyde, a problem common to many amine oxidases and dehydrogenases. Using a novel synthetic in vivo reporter system for cellular formaldehyde, we found that the oxidation of dimethylglycine is coupled to the synthesis of 5,10-methylenetetrahydrofolate through an unusual substrate channeling mechanism. We also showed that uncoupling of the active sites could be achieved by mutagenesis or deletion of the 5,10-methylenetetrahydrofolate synthase site and that 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. This central "reaction chamber" is created by a modular protein architecture that appears primitive when compared with the sophisticated design of other paradigm substrate-channeling enzymes. The evolutionary origins of the latter were likely similar to dimethylglycine oxidase. This work demonstrates the utility of synthetic biology approaches to the study of enzyme mechanisms in vivo and points to novel channeling mechanisms that protect the cell milieu from potentially toxic reaction products.

PubMed: 19369258
DOI: 10.1074/jbc.M109.006262

Experimental method

X-RAY DIFFRACTION (2 Å)