CatA (catA-I, PP_3713) is the principal catechol 1,2-dioxygenase (EC 1.13.11.1) of Pseudomonas putida KT2440, a cytoplasmic non-heme Fe(III) intradiol ring-cleavage dioxygenase that cleaves catechol between its two hydroxylated carbons to give cis,cis-muconate. This is the first step of the catechol ortho-cleavage branch of the beta-ketoadipate pathway, through which KT2440 degrades benzoate and other aromatics funnelled to catechol by the ben upper pathway; CatB and CatC then convert cis,cis-muconate to beta-ketoadipate enol-lactone. catA lies in the CatR-regulated catBCA region, induced by cis,cis-muconate. KT2440 carries a second, ben-linked paralog, CatA-II (PP_3166), which relieves catechol surplus during benzoate catabolism.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0003824 catalytic activity | IEA GO_REF:0000002 | MODIFY | Summary: Root catalytic term; true but uninformative for an enzyme assigned to the proteobacterial catechol 1,2-dioxygenase family. Reason: Correct but general; replace with GO:0018576, accepted below. Proposed replacements: catechol 1,2-dioxygenase activity Supporting Evidence: file:PSEPK/catA/catA-uniprot.txt DR NCBIfam; TIGR02439; catechol_proteo; 1. |
| GO:0005506 iron ion binding | IEA GO_REF:0000002 | MODIFY | Summary: Correct, but intradiol dioxygenases use Fe(III) specifically. Reason: Refine to GO:0008199 ferric iron binding, accepted below. Proposed replacements: ferric iron binding Supporting Evidence: PMID:10801478 Catechol 1,2-dioxygenases (1, 2-CTDs) have a rudimentary design structure - a homodimer with one catalytic non-heme ferric ion per monomer |
| GO:0008199 ferric iron binding | IEA GO_REF:0000002 | ACCEPT | Summary: Catechol 1,2-dioxygenases carry one catalytic Fe(III) per subunit, bound by conserved His and Tyr ligands; Q88GK8 carries the intradiol dioxygenase signature and the proteobacterial catechol 1,2-dioxygenase family model, whose structurally characterised member (A. baylyi ADP1 CatA) binds Fe(III). Reason: Catalytic cofactor binding, supported by family membership and by the structure of a close ortholog. Supporting Evidence: PMID:10801478 Catechol 1,2-dioxygenases (1, 2-CTDs) have a rudimentary design structure - a homodimer with one catalytic non-heme ferric ion per monomer PMID:3170486 conserved histidyl and tyrosyl residues that are probably involved in the ligation of ferric ion in their active sites file:PSEPK/catA/catA-uniprot.txt DR PROSITE; PS00083; INTRADIOL_DIOXYGENAS; 1. |
| GO:0009712 catechol-containing compound metabolic process | IEA GO_REF:0000002 | MODIFY | Summary: Correct but general; CatA initiates catechol catabolism by ortho-cleavage. Reason: Refine to GO:0019615 catechol catabolic process, ortho-cleavage, an is_a descendant of this term. Proposed replacements: catechol catabolic process, ortho-cleavage Supporting Evidence: PMID:24341396 one ortho pathway determined by the chromosomal ben and cat genes |
| GO:0016702 oxidoreductase activity, acting on single donors with incorporation of molecular oxygen, incorporation of two atoms of oxygen | IEA GO_REF:0000002 | MODIFY | Summary: Correct dioxygenase grouping term; the specific activity is catechol 1,2-dioxygenation. Reason: Refine to GO:0018576, the specific descendant activity. Proposed replacements: catechol 1,2-dioxygenase activity Supporting Evidence: file:PSEPK/catA/catA-uniprot.txt DR NCBIfam; TIGR02439; catechol_proteo; 1. |
| GO:0018576 catechol 1,2-dioxygenase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Core activity. CatA-I belongs to the proteobacterial catechol 1,2-dioxygenase family, sits in the cat gene region of the KT2440 ortho pathway, and genetic work in the KT2440 lineage compares strains lacking CatA, its paralog CatA2, or both. Reason: Family membership, genomic context and mutant analysis in P. putida mt-2/KT2440 converge on this activity. No purified-enzyme kinetics for Q88GK8 itself are in the cached literature. Supporting Evidence: file:PSEPK/catA/catA-uniprot.txt DR NCBIfam; TIGR02439; catechol_proteo; 1. PMID:24341396 P. putida mt-2 has a second chromosomal copy of the catA gene (named catA2) located downstream of the ben operon that encodes an additional catechol-1,2-dioxygenase. PMID:12534466 the protocatechuate (pca genes) and catechol (cat genes) branches of the beta-ketoadipate pathway file:PSEPK/catA/catA-deep-research-falcon.md Direct genetic and biochemical evidence shows CatA (PP_3713) provides the bulk of C1,2O capacity in KT2440 |
| GO:0019614 catechol-containing compound catabolic process | IEA GO_REF:0000002 | MODIFY | Summary: Correct but general; the route is specifically ortho-cleavage. Reason: Refine to GO:0019615, an is_a child of this term and of GO:0042952 beta-ketoadipate pathway. Proposed replacements: catechol catabolic process, ortho-cleavage Supporting Evidence: PMID:12534466 the protocatechuate (pca genes) and catechol (cat genes) branches of the beta-ketoadipate pathway |
| GO:0042952 beta-ketoadipate pathway | IEA GO_REF:0000041 | MODIFY | Summary: Correct pathway; CatA acts in the catechol branch, not the protocatechuate branch. Reason: Refine to GO:0019615, the is_a child of the beta-ketoadipate pathway restricted to the catechol branch. Proposed replacements: catechol catabolic process, ortho-cleavage Supporting Evidence: PMID:21906639 The mutant was no longer able to grow using benzoate as a sole carbon source, but co-metabolized benzoate to cis, cis-muconate during growth on glucose, which accumulated in the growth medium. |
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Download this section (compressed HTML)Q: How do CatA-I and CatA-II partition catechol flux in KT2440 during growth on benzoate versus phenol or catechol?
Suggested experts: Pseudomonas aromatic-catabolism researchers
Experiment: Purify KT2440 CatA-I and CatA-II and compare Km and kcat for catechol and methylcatechols, and inhibition by excess catechol.
Type: enzyme kinetics
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