DB code: S00852

RLCP classification 4.1034.143290.135 : Addition
8.113.46500.4 : Isomerization
CATH domain 2.130.10.10 : Methylamine Dehydrogenase; Chain H Catalytic domain
E.C. 5.5.1.5
CSA 1jof
M-CSA 1jof
MACiE

CATH domain Related DB codes (homologues)
2.130.10.10 : Methylamine Dehydrogenase; Chain H D00039 M00329

Uniprot Enzyme Name
UniprotKB Protein name Synonyms RefSeq Pfam
P38677 Carboxy-cis,cis-muconate cyclase
EC 5.5.1.5
3-carboxy-cis,cis-muconate lactonizing enzyme
CMLE
XP_957686.1 (Protein)
XM_952593.1 (DNA/RNA sequence)
PF10282 (Lactonase)
[Graphical View]

KEGG enzyme name
Carboxy-cis,cis-muconate cyclase
3-Carboxymuconate cyclase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P38677 CMLE_NEUCR 3-Carboxy-2,5-dihydro-5-oxofuran-2-acetate = 3-carboxy-cis,cis-muconate. Homotetramer. Does not require divalent cations for activity.

KEGG Pathways
Map code Pathways E.C.
MAP00362 Benzoate degradation via hydroxylation

Compound table
Substrates Products Intermediates
KEGG-id C01163 C04553 I00068
E.C.
Compound 3-Carboxy-cis,cis-muconate 3-Carboxy-2,5-dihydro-5-oxofuran-2-acetate 3-carboxy-2,5-dihydro-5-oxofuran-2-enolate
Type carboxyl group carboxyl group,aromatic ring (with hetero atoms other than nitrogen atoms)
ChEBI 15749
16989
PubChem 5280404
440383
1jofA00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1jofB00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1jofC00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1jofD00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1jofE00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1jofF00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1jofG00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound
1jofH00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.
literature [4]

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1jofA00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274
1jofB00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274
1jofC00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274
1jofD00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274
1jofE00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274
1jofF00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274
1jofG00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274
1jofH00 Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain HIS 148;ARG 196;GLU 212;ARG 274

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[4]
Fig.3, p.488

References
[1]
Resource
Comments
Medline ID
PubMed ID 8132467
Journal J Bacteriol
Year 1994
Volume 176
Pages 1718-28
Authors Mazur P, Henzel WJ, Mattoo S, Kozarich JW
Title 3-Carboxy-cis,cis-muconate lactonizing enzyme from Neurospora crassa: an alternate cycloisomerase motif.
Related PDB
Related UniProtKB
[2]
Resource
Comments
Medline ID
PubMed ID 15299752
Journal Acta Crystallogr D Biol Crystallogr
Year 1996
Volume 52
Pages 221-3
Authors Glumoff T, Helin S, Mazur P, Kozarich JW, Goldman A
Title Crystallization and preliminary crystallographic analysis of 3-carboxy-cis,cis-muconate lactonizing enzyme from Neurospora crassa.
Related PDB
Related UniProtKB
[3]
Resource
Comments
Medline ID
PubMed ID 11976482
Journal Acta Crystallogr D Biol Crystallogr
Year 2002
Volume 58
Pages 727-34
Authors Merckel MC, Kajander T, Deacon AM, Thompson A, Grossmann JG, Kalkkinen N, Goldman A
Title 3-Carboxy-cis,cis-muconate lactonizing enzyme from Neurospora crassa: MAD phasing with 80 selenomethionines.
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 11937053
Journal Structure
Year 2002
Volume 10
Pages 483-92
Authors Kajander T, Merckel MC, Thompson A, Deacon AM, Mazur P, Kozarich JW, Goldman A
Title The structure of Neurospora crassa 3-carboxy-cis,cis-muconate lactonizing enzyme, a beta propeller cycloisomerase.
Related PDB 1jof
Related UniProtKB

Comments
According to the literature [3] and [4], the muconate lactonizing enzymes (MLEs) convert cis,cis-muconates into muconolactones, as a part of the beta-ketoadipate pathway. This pathway consists of two branches, catechol (MLEs; E.C. 5.5.1.1) and protocatechuate (3-carboxy-cis,cis-MLEs or CMLEs; E.C. 5.5.1.2) (see [3] and [4]).
Moreover, MLEs can be classified into three evolutionarily distinct classes (see [3] and [4]). Firstly, bacterial MLEs catalyze a syn addition, using a Mn2+ cofactor with a TIM barrel fold as the catalitic domain (D00282 in EzCatDB). Secondly, bacterial CMLEs (PDB;1q5n) catalyze an anti addition, without metal cofactor on a fold, which is related to class II fumarase (T00086) family (CATH 1.20.200.10). Thirdly, both eukaryotic MLEs and CMLEs catalyze a syn addition, without metal cofactor. This entry belongs to the CMLEs in the third class.
According to the literature [4], this enzyme catalyzes an intramolecular addition reaction and an isomerization, through an enolate intermediate, as follows:
(A) Addition of carboxylate oxygen to the C4 double-bonded carbon, forming an enolate intermediate:
(A1) The sidechains of Arg196 and Arg274 seem to modulate and increase the nucleophilicity of the C1 carboxylate of the substrate, 3-carboxylate-cis,cis-muconate, by interacting with it.
(A2) The C1 carboxylate oxygen makes a nucleophilic attack on the C4 (sp2) carbon, whereas Glu212 acts as a general acid to protonate the C6 carboxylate. The reactions lead to the formation of an enolate intermediate.
(B) Isomerization; Shift of double-bond position (from C=C-O to C-C=O):
(B1) His148 seems to act as a general acid to protonate the C5 carbon in the enolate intermediate. (Here, Glu212 must act as a general base to deprotonate the C6 enolate oxygen. Otherwise, it must be difficult to convert the enolate intermediate to the product.)
## Although the literature [4] described His148 as a general base, it seems to act as a general acid in the forward reaction (from the substrate to product). However, it will be a genral base in the reverse reaction.

Created Updated
2009-09-09 2010-08-05