MetaCyc Enzyme: 3-carboxymuconate cycloisomerase

Gene: pcaB Accession Number: G-2287 (MetaCyc)

Synonyms: β-carboxy-cis,cis-muconate lactonizing enzyme, 3-carboxy-cis,cis-muconate lactonizing enzyme, CMLE

Species: Pseudomonas putida

Subunit composition of 3-carboxymuconate cycloisomerase = [PcaB]4
         subunit of 3-carboxymuconate cycloisomerase = PcaB

The deduced amino acid sequence of 3-carboxymuconate cycloisomerase (CMLE) has significant sequence homology to the class II fumarase family of proteins [Williams92]. Contrarily, CMLE has no significant similarity to cis, cis-muconate lactonizing enzyme (MLE), the enzyme which catalyzes the analogous reaction in the catechol branch of the β-ketodadipate pathway. The reaction mechanisms of CMLE and MLE were also found to be different; while CMLE catalyzes an anti-cycloisomerization reaction, MLE catalyzes a syn- syn-cycloisomerization reaction (as reported in [Williams92]). These findings suggest that CMLE and MLE have a remote evolutionary relationship despite that they catalyze similar reactions [Williams92].

The KM for 3-carboxy-cis,cis-muconate was shown to be 32 [Williams92], and 75 [Ornston66] μM.

3-Carboxymuconate cycloisomerase is induced by β-ketoadipate [Ornston66a, Harwood96].

Molecular Weight of Polypeptide: 42.4 kD (from nucleotide sequence), 43 kD (experimental) [Williams92 ], 40 kD (experimental) [Patel73 ]

Molecular Weight of Multimer: 190 kD (experimental) [Patel73]

Unification Links: ModBase:P32427 , Protein Model Portal:P32427 , SMR:P32427 , Swiss-Model:P32427 , UniProt:P32427

Relationship Links: InterPro:IN-FAMILY:IPR000362 , InterPro:IN-FAMILY:IPR008948 , InterPro:IN-FAMILY:IPR012789 , InterPro:IN-FAMILY:IPR019468 , InterPro:IN-FAMILY:IPR020557 , InterPro:IN-FAMILY:IPR022761 , InterPro:IN-FAMILY:IPR024083 , Panther:IN-FAMILY:PTHR11444 , Pfam:IN-FAMILY:PF00206 , Pfam:IN-FAMILY:PF10397 , Prints:IN-FAMILY:PR00149 , Prosite:IN-FAMILY:PS00163 , Smart:IN-FAMILY:SM00998

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Enzymatic reaction of: 3-carboxymuconate cycloisomerase

EC Number:

2-carboxy-5-oxo-2,5-dihydrofuran-2-acetate <=> 3-carboxy-cis,cis-muconate + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.

The reaction is favored in the opposite direction.

In Pathways: superpathway of aromatic compound degradation via 3-oxoadipate , aromatic compounds degradation via β-ketoadipate , protocatechuate degradation II (ortho-cleavage pathway)

Citations: [Patel73, Williams92]

Inhibitors (Competitive): potassium chloride [Williams92]

Inhibitors (Unknown Mechanism): Cu2+ [Ornston66] , Ni2+ [Ornston66] , Co2+ [Ornston66]


Harwood96: Harwood CS, Parales RE (1996). "The beta-ketoadipate pathway and the biology of self-identity." Annu Rev Microbiol 50;553-90. PMID: 8905091

Ornston66: Ornston LN (1966). "The conversion of catechol and protocatechuate to beta-ketoadipate by Pseudomonas putida. II. Enzymes of the protocatechuate pathway." J Biol Chem 241(16);3787-94. PMID: 5916392

Ornston66a: Ornston LN (1966). "The conversion of catechol and protocatechuate to beta-ketoadipate by Pseudomonas putida. IV. Regulation." J Biol Chem 241(16);3800-10. PMID: 5916393

Patel73: Patel RN, Meagher RB, Ornston LN (1973). "Relationships among enzymes of the beta-ketoadipate pathway. II. Properties of crystalline beta-carboxy-cis,cis-muconate-lactonizing enzyme from Pseudomonas putida." Biochemistry 12(18);3531-7. PMID: 4199895

Williams92: Williams SE, Woolridge EM, Ransom SC, Landro JA, Babbitt PC, Kozarich JW (1992). "3-Carboxy-cis,cis-muconate lactonizing enzyme from Pseudomonas putida is homologous to the class II fumarase family: a new reaction in the evolution of a mechanistic motif." Biochemistry 31(40);9768-76. PMID: 1390752

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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