This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Degradation/Utilization/Assimilation → Aromatic Compounds Degradation → Gallate Degradation|
Expected Taxonomic Range:
Gallate and structurally related compounds are widely distributed in nature. Plant lignin and tannins are major sources of these compounds, which are degraded by soil microorganisms as part of the terrestrial carbon cycle. Gallate is also used industrially in inks and paints, and gallate esters are used as food, cosmetics and pharmaceutical antioxidants. Gallate and its derivatives are also of interest in drug development (reviewed in [Ow03].
Gallate and related compounds contain a benzene nucleus and at least 2 phenolic hydroxyl groups. Under aerobic conditions the benzene ring is cleaved by varioius dioxygenases. The benzene nucleus can be cleaved by ortho or meta fission enzymes, leading to different degradation pathways. Several distinct pathways of aerobic aromatic catabolism can be initiated by these dioxygenases, and their distribution among bacteria is complex [Gottschalk86]. Examples of these oxidative pathways are shown in MetaCyc pathways gallate degradation II, methylgallate degradation, protocatechuate degradation I (meta-cleavage pathway), protocatechuate degradation II (ortho-cleavage pathway), and superpathway of aromatic compound degradation via 3-oxoadipate. An anaerobic pathway for gallate degradation is shown in MetaCyc pathway gallate degradation III (anaerobic).
About This Pathway
Gallate dioxygenase is a ring-cleavage dioxygenase found in several gallate-degrading organisms that acts specifically on gallate to produce the keto-tautomer of 4-oxalomesaconate [Nogales05, Nogales10]. The enzyme shares a common ancestor with protocatechuate 4,5-dioxygenase, and has a two-domain architecture that might have evolved from the fusion of the large and small subunits of the latter. In some organisms, such as Comamonas testosteroni, it has been shown that protocatechuate 4,5-dioxygenase can catalyze the same reaction, although with lower efficiency [Zabinski72].
The product of the ring cleavage is the keto tautomer of 4-oxalomesaconate, (1E)-4-oxobut-1-ene-1,2,4-tricarboxylate [Nogales10]. While it can form the enol form, (1Z,3Z)-4-hydroxybuta-1,3-diene-1,2,4-tricarboxylate, spontaneously, it has been shown that in Pseudomonas putida KT2440 a dedicated enzyme, 4-oxalomesaconate tautomerase, catalyzes this conversion [Nogales10].
The enol form is the substrate for 4-oxalomesaconate hydratase [Hara00], and the product of this enzyme, 2-hydroxy-4-oxobutane-1,2,4-tricarboxylate, is cleaved by an aldolase to oxaloacetate and pyruvate, which enter central metabolism [Hara03].
Fluorescent pseudomonads, such as Pseudomonas putida, can also cleave gallate by the ortho cleavage enzyme protocatechuate 3,4-dioxygenase, resulting in formation of the lactone 2-pyrone-4,6-dicarboxylate (see MetaCyc pathway gallate degradation II).
Superpathways: syringate degradation
Hara00: Hara H, Masai E, Katayama Y, Fukuda M (2000). "The 4-oxalomesaconate hydratase gene, involved in the protocatechuate 4,5-cleavage pathway, is essential to vanillate and syringate degradation in Sphingomonas paucimobilis SYK-6." J Bacteriol 182(24);6950-7. PMID: 11092855
Hara03: Hara H, Masai E, Miyauchi K, Katayama Y, Fukuda M (2003). "Characterization of the 4-carboxy-4-hydroxy-2-oxoadipate aldolase gene and operon structure of the protocatechuate 4,5-cleavage pathway genes in Sphingomonas paucimobilis SYK-6." J Bacteriol 185(1);41-50. PMID: 12486039
Kersten82: Kersten PJ, Dagley S, Whittaker JW, Arciero DM, Lipscomb JD (1982). "2-pyrone-4,6-dicarboxylic acid, a catabolite of gallic acids in Pseudomonas species." J Bacteriol 1982;152(3);1154-62. PMID: 7142106
Nogales05: Nogales J, Canales A, Jimenez-Barbero J, Garcia JL, Diaz E (2005). "Molecular characterization of the gallate dioxygenase from Pseudomonas putida KT2440: The prototype of a new subgroup of extradiol dioxygenases." J Biol Chem 280(42):35382-90. PMID: 16030014
Nogales10: Nogales, J., Canales, A., Jimenez-barbero, J., Serra, B., Pingarron, J. M., Garcia, J. L., Diaz, E. (2010). "Unravelling the gallic acid degradation pathway in bacteria: the gal cluster from Pseudomonas putida." Molecular Microbiology, 79:359-374. PMID: 21219457
Arciero83: Arciero DM, Lipscomb JD, Huynh BH, Kent TA, Munck E (1983). "EPR and Mossbauer studies of protocatechuate 4,5-dioxygenase. Characterization of a new Fe2+ environment." J Biol Chem 258(24);14981-91. PMID: 6317682
Kasai04: Kasai D, Masai E, Miyauchi K, Katayama Y, 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(15);4951-9. PMID: 15262932
Kasai05: Kasai D, Masai E, Miyauchi K, Katayama Y, Fukuda M (2005). "Characterization of the gallate dioxygenase gene: three distinct ring cleavage dioxygenases are involved in syringate degradation by Sphingomonas paucimobilis SYK-6." J Bacteriol 187(15);5067-74. PMID: 16030198
Mampel05: Mampel J, Providenti MA, Cook AM (2005). "Protocatechuate 4,5-dioxygenase from Comamonas testosteroni T-2: biochemical and molecular properties of a new subgroup within class III of extradiol dioxygenases." Arch Microbiol 183(2);130-9. PMID: 15650824
Maruyama01: Maruyama K, Miwa M, Tsujii N, Nagai T, Tomita N, Harada T, Sobajima H, Sugisaki H (2001). "Cloning, sequencing, and expression of the gene encoding 4-hydroxy-4-methyl-2-oxoglutarate aldolase from Pseudomonas ochraceae NGJ1." Biosci Biotechnol Biochem 65(12);2701-9. PMID: 11826967
Maruyama90: Maruyama K (1990). "Purification and properties of 4-hydroxy-4-methyl-2-oxoglutarate aldolase from Pseudomonas ochraceae grown on phthalate." J Biochem (Tokyo) 1990;108(2);327-33. PMID: 2229032
Masai00: Masai E, Momose K, Hara H, Nishikawa S, Katayama Y, Fukuda M (2000). "Genetic and biochemical characterization of 4-carboxy-2-hydroxymuconate-6-semialdehyde dehydrogenase and its role in the protocatechuate 4,5-cleavage pathway in Sphingomonas paucimobilis SYK-6." J Bacteriol 182(23);6651-8. PMID: 11073908
Masai99: Masai E, Shinohara S, Hara H, Nishikawa S, Katayama Y, Fukuda M (1999). "Genetic and biochemical characterization of a 2-pyrone-4, 6-dicarboxylic acid hydrolase involved in the protocatechuate 4, 5-cleavage pathway of Sphingomonas paucimobilis SYK-6." J Bacteriol 181(1);55-62. PMID: 9864312
Noda90: Noda Y, Nishikawa S, Shiozuka K, Kadokura H, Nakajima H, Yoda K, Katayama Y, Morohoshi N, Haraguchi T, Yamasaki M (1990). "Molecular cloning of the protocatechuate 4,5-dioxygenase genes of Pseudomonas paucimobilis." J Bacteriol 172(5);2704-9. PMID: 2185230
Nogales11: Nogales J, Canales A, Jimenez-Barbero J, Serra B, Pingarron JM, Garcia JL, Diaz E (2011). "Unravelling the gallic acid degradation pathway in bacteria: the gal cluster from Pseudomonas putida." Mol Microbiol 79(2);359-74. PMID: 21219457
Providenti01: Providenti MA, Mampel J, MacSween S, Cook AM, Wyndham RC (2001). "Comamonas testosteroni BR6020 possesses a single genetic locus for extradiol cleavage of protocatechuate." Microbiology 147(Pt 8);2157-67. PMID: 11495993
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