AC MF_01989; DC Protein; auto TR HAMAP; MF_01989; -; 1; level=0 XX Names: Cyc_amidohydrol XX case and and and ID CAH DE RecName: Full=Cyanuric acid amidohydrolase; DE Short=CAH; DE EC=3.5.2.15; else case and and and ID BAH DE RecName: Full=Barbiturase; DE EC=3.5.2.1; DE AltName: Full=Barbituric acid hydrolase; DE Short=BAH; else ID CYAH DE RecName: Full=Cyclic amide hydrolase; DE Short=CyAH; DE EC=3.5.2.-; DE AltName: Full=Ring-opening amidohydrolase; end case XX case and and and CC -!- FUNCTION: Responsible for the hydrolysis of cyanuric acid, an CC intermediate formed during catabolism of s-triazine based compounds in CC herbicides such as atrazine and polymers such as melamine. Catalyzes CC the hydrolytic opening of the s-triazine ring of cyanuric acid (2,4,6- CC trihydroxy-s-triazine) to yield carbon dioxide and carboxybiuret, which CC spontaneously decarboxylates to biuret. CC -!- CATALYTIC ACTIVITY: CC Reaction=cyanurate + H2O = 1-carboxybiuret + H(+); CC Xref=Rhea:RHEA:70363, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, CC ChEBI:CHEBI:38028, ChEBI:CHEBI:142864; EC=3.5.2.15; CC -!- ACTIVITY REGULATION: Inhibited by barbituric acid. CC -!- PATHWAY: Xenobiotic degradation; atrazine degradation; biuret from CC cyanurate: step 1/1. CC -!- DOMAIN: The monomer structure is formed from three repeating units CC (RUs) that share the same structure as one another. The monomer, the CC active site and substrate all possess threefold rotational symmetry, to CC the extent that the active site possesses three potential Ser-Lys CC catalytic dyads. It is possible that any or all of the three active- CC site serines may act as nucleophile (albeit only one can do so per CC catalytic cycle). else case and and and CC -!- FUNCTION: Responsible for the hydrolysis of barbituric acid (2,4,6- CC trihydroxy-1,3-pyrimidine), an intermediate in the oxidative catabolism CC of pyrimidines. Catalyzes the hydrolytic opening of the pyrimidine ring CC of barbituric acid to yield ureidomalonic acid. CC -!- CATALYTIC ACTIVITY: CC Reaction=barbiturate + H2O = 3-oxo-3-ureidopropanoate; CC Xref=Rhea:RHEA:18653, ChEBI:CHEBI:15377, ChEBI:CHEBI:58775, CC ChEBI:CHEBI:77938; EC=3.5.2.1; CC -!- ACTIVITY REGULATION: Inhibited by cyanuric acid. CC -!- PATHWAY: Pyrimidine metabolism; uracil degradation via oxidative CC pathway; malonate and urea from uracil: step 2/3. CC -!- DOMAIN: The monomer structure is formed from three repeating units CC (RUs) that share the same structure as one another. The monomer and the CC active site possess nearly threefold rotational symmetry, to the extent CC that the active site possesses three potential Ser-Lys catalytic dyads, CC but one of the 3 active site surfaces varies in composition suggesting CC it is involved in confering substrate specificity. else CC -!- FUNCTION: Cyclic amide hydrolase of unknown substrate specificity. CC Catalyzes the hydrolytic ring-opening of a cyclic amide. Does not act CC on cyanuric acid nor barbituric acid. CC -!- DOMAIN: The monomer structure is formed from three repeating units CC (RUs) that share the same structure as one another. The monomer and the CC active site possess nearly threefold rotational symmetry, to the extent CC that the active site possesses three potential Ser-Lys catalytic dyads, CC but one of the 3 active site surfaces varies in composition suggesting CC it is involved in confering substrate specificity. end case case CC -!- SUBUNIT: Homotetramer; disulfide-linked. The disufides form between 2 CC monomers in the tetramer, such that each tetramer contains 2 sets of CC vicinal disulfides. else CC -!- SUBUNIT: Homotetramer. end case CC -!- SIMILARITY: Belongs to the cyclic amide hydrolase (CyAH) family. XX DR Pfam; PF09663; Amido_AtzD_TrzD; 1; trigger=no DR NCBIfam; TIGR02714; amido_AtzD_TrzD; 1; trigger=no XX KW Hydrolase case KW Magnesium KW Metal-binding end case XX case and and and GO GO:0018753; F:cyanuric acid amidohydrolase activity GO GO:0019381; P:atrazine catabolic process else case and and and GO GO:0047694; F:barbiturase activity GO GO:0006212; P:uracil catabolic process else GO GO:0016812; F:hydrolase activity, acting on carbon-nitrogen (but not peptide) bonds, in cyclic amides end case case GO GO:0046872; F:metal ion binding end case XX FT From: CAH_PSESD (P58329) FT REGION Nter..103 FT /note="RU A" FT BINDING 83..84 FT /ligand="substrate" FT Condition: S-G FT REGION 112..249 FT /note="RU B" FT BINDING 232..233 FT /ligand="substrate" FT Condition: S-[SAG] FT REGION 255..Cter FT /note="RU C" FT BINDING 343..344 FT /ligand="substrate" FT Tag: CAH3; Optional; Condition: S-G FT BINDING 343..344 FT /ligand="substrate" FT Tag: BAH3; Optional; Condition: S-V FT BINDING 343..344 FT /ligand="substrate" FT Optional; Condition: S-[AT] FT BINDING 297 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="structural" FT Group: 1; Condition: [ED] FT BINDING 346 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="structural" FT Group: 1; Condition: [ASG] FT BINDING 349 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="structural" FT Group: 1; Condition: Q FT BINDING 350 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="structural" FT Group: 1; Condition: G FT BINDING 351 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="structural" FT Group: 1; Condition: P FT BINDING 354 FT /ligand="Mg(2+)" FT /ligand_id="ChEBI:CHEBI:18420" FT /ligand_note="structural" FT Group: 1; Condition: G FT BINDING 52 FT /ligand="substrate" FT Condition: R FT BINDING 194 FT /ligand="substrate" FT Tag: CAH1; Optional; Condition: R FT BINDING 194 FT /ligand="substrate" FT Tag: BAH1; Optional; Condition: N FT BINDING 324 FT /ligand="substrate" FT Tag: CAH2; Optional; Condition: R FT BINDING 324 FT /ligand="substrate" FT Tag: BAH2; Optional; Condition: K FT SITE 320 FT /note="Important for substrate specificity" FT Tag: CAH4; Optional; Condition: [ST] FT SITE 320 FT /note="Important for substrate specificity" FT Tag: BAH4; Optional; Condition: [H] FT From: CAH_AZOC5 (A8IKD2) FT ACT_SITE 156 FT Condition: K FT ACT_SITE 226 FT /note="Nucleophile" FT Condition: S FT From: CYAH_PSEI1 (E3JD18) FT DISULFID 303 FT /note="Interchain (with #{Cys-304})" FT Optional; Group: 2; Condition: C FT DISULFID 304 FT /note="Interchain (with #{Cys-303})" FT Optional; Group: 2; Condition: C XX Size: 341-390; Related: None; Template: P58329; A8IKD2; E3JD18; Q8RSQ2; Scope: Bacteria Eukaryota; Fungi Fusion: Nter: None Cter: None Duplicate: in AZOC5, NOCSJ, RHOSO Plasmid: in ENTCL, PSESD, RHILS, RHOSO Comments: None XX # Revision 1.12 2023/11/29 //