PMID:15262932

Citation	Kasai, D, Masai, E, Miyauchi, K, Katayama, Y and Fukuda, M (2004) Characterization of the 3-O-methylgallate dioxygenase gene and evidence of multiple 3-O-methylgallate catabolic pathways in Sphingomonas paucimobilis SYK-6. J. Bacteriol. 186:4951-9
Abstract	Sphingomonas paucimobilis SYK-6 is able to grow on various lignin-derived biaryls as the sole source of carbon and energy. These compounds are degraded to vanillate and syringate by the unique and specific enzymes in this strain. Vanillate and syringate are converted to protocatechuate (PCA) and 3-O-methylgallate (3MGA), respectively, by the tetrahydrofolate-dependent O-demethylases. Previous studies have suggested that these compounds are further degraded via the PCA 4,5-cleavage pathway. However, our subsequent analysis of the ligB insertion mutant, which encodes the beta subunit of PCA 4,5-dioxygenase, suggested that at least one alternative route is involved in 3MGA degradation. In the present study, we isolated the desZ gene, which confers 3MGA degradation activity on Escherichia coli. The deduced amino acid sequence of desZ showed ca. 20 to 43% identity with the type II extradiol dioxygenases. Gas chromatography-mass spectrometry analysis suggested that DesZ catalyzes the 3,4-cleavage of 3MGA. Disruption of both desZ and ligB in SYK-6 resulted in loss of the dioxygen-dependent 3MGA transformation activity, but the resulting mutant retained the ability to grow on syringate. We found that the cell extract of the desZ ligB double mutant was able to convert 3MGA to gallate when tetrahydrofolate was added to the reaction mixture, and the cell extract of this mutant degraded gallate to the same degree as the wild type did. All these results suggest that syringate is degraded through multiple 3MGA degradation pathways in which ligAB, desZ, 3MGA O-demethylase, and gallate dioxygenase are participants.
Links	PubMed PMC451629 Online version:10.1128/JB.186.15.4951-4959.2004
Keywords	Biodegradation, Environmental; Escherichia coli/enzymology; Escherichia coli/genetics; Gallic Acid/analogs & derivatives; Gallic Acid/metabolism; Gas Chromatography-Mass Spectrometry; Gene Expression Regulation, Bacterial; Molecular Sequence Data; Oxidoreductases, O-Demethylating/metabolism; Oxygenases/chemistry; Oxygenases/genetics; Oxygenases/metabolism; Sphingomonas/enzymology; Sphingomonas/genetics; Sphingomonas/growth & development
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
PSEPA:Q7WYU8		GO:0016702: oxidoreductase activity, acting on single donors with incorporation of molecular oxygen, incorporation of two atoms of oxygen	ECO:0000314:		F		Fig 4. desZ molecular activity is shown by analysis of nuclear magnetic resonance at the various time intervals of growth that that enzymatic function of desZ is the incorporation of oxygen molecules on to the substrate	complete CACAO 4940
PSEPA:PCYB		GO:0006725: cellular aromatic compound metabolic process	ECO:0000314:		P		Fig 5. lanes 8 and 11 show the ability of ligB mutants to metabolize 3-O-methylgallate as a carbon source.	complete CACAO 4956

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