DB code: S00341

RLCP classification 1.13.30100.49 : Hydrolysis
CATH domain 3.40.50.850 : Rossmann fold Catalytic domain
E.C. 3.5.1.59
CSA 1nba
M-CSA 1nba
MACiE M0025

CATH domain Related DB codes (homologues)

Uniprot Enzyme Name
UniprotKB Protein name Synonyms Pfam
P32400 N-carbamoylsarcosine amidase
EC 3.5.1.59
N-carbamoylsarcosine amidohydrolase
CSHase
PF00857 (Isochorismatase)
[Graphical View]

KEGG enzyme name
N-carbamoylsarcosine amidase
carbamoylsarcosine amidase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P32400 CSH_ARTSP N-carbamoylsarcosine + H(2)O = sarcosine + CO(2) + NH(3). Homotetramer. Binds 1 sulfate ion per subunit.

KEGG Pathways
Map code Pathways E.C.
MAP00330 Arginine and proline metabolism

Compound table
Cofactors Substrates Products Intermediates
KEGG-id C00059 C01043 C00001 C00213 C00011 C00014
E.C.
Compound Sulfate N-Carbamoylsarcosine H2O Sarcosine CO2 NH3
Type sulfate group amino acids,amide group,amine group H2O amino acids others amine group,organic ion
ChEBI 26836
15737
15377
15611
57433
16526
16134
PubChem 1118
22066174
5152822
439375
22247451
962
1088
7311726
280
222
1nbaA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:SO4 Unbound Unbound Unbound Unbound
1nbaB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:SO4 Unbound Unbound Unbound Unbound
1nbaC Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:SO4 Unbound Unbound Unbound Unbound
1nbaD Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Bound:SO4 Unbound Unbound Unbound Unbound

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

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1nbaA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177
1nbaB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177
1nbaC Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177
1nbaD Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[1]
p.1128
[2]
p.278-279
[3]
p.256-257 8
[4]
Fig.6 5

References
[1]
Resource
Comments X-ray crystallography (2.0 Angstroms)
Medline ID
PubMed ID 1381445
Journal J Mol Biol
Year 1992
Volume 226
Pages 1111-30
Authors Romao MJ, Turk D, Gomis-Ruth FX, Huber R, Schumacher G, Mollering H, Russmann L
Title Crystal structure analysis, refinement and enzymatic reaction mechanism of N-carbamoylsarcosine amidohydrolase from Arthrobacter sp. at 2.0 A resolution.
Related PDB 1nba
Related UniProtKB
[2]
Resource
Comments X-ray crystallography (2.28 Angstroms)
Medline ID 97070380
PubMed ID 8913306
Journal J Mol Biol
Year 1996
Volume 263
Pages 269-83
Authors Zajc A., Romao M.J., Turk D., Huber R
Title Crystallographic and fluorescence studies of ligand binding to N-carbamoylsarcosine amidohydrolase from Arthrobacter sp.
Related PDB
Related UniProtKB
[3]
Resource
Comments
Medline ID
PubMed ID 11237598
Journal J Mol Biol
Year 2001
Volume 306
Pages 251-61
Authors Wang WC, Hsu WH, Chien FT, Chen CY
Title Crystal structure and site-directed mutagenesis studies of N-carbamoyl-D-amino-acid amidohydrolase from Agrobacterium radiobacter reveals a homotetramer and insight into a catalytic cleft.
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 11714269
Journal Biochemistry
Year 2001
Volume 40
Pages 14166-72
Authors Du X, Wang W, Kim R, Yakota H, Nguyen H, Kim SH
Title Crystal structure and mechanism of catalysis of a pyrazinamidase from Pyrococcus horikoshii.
Related PDB
Related UniProtKB

Comments
All the literature reported that Cys177 of this enzyme, CSHase, is the nucleophilic residue that will attack the carbamoyl carbon atom of the substrate to form a covalent bond with the atom (see [1], [2], [3] & [4]).
The paper on the other enzyme, which is not homologous but has got a similar active site, and then probably will adopt the similar catalytic mechanism, mentioned that CSHase also have the Cys-Asp-Lys catalytic triad. According to the literature [4] on the homologous enzyme of CSHase, Asp51, Lys144 and Cys177 form the catalytic triad, whilst the consecutive cis-peptide bond residues, Ala172-Thr173, could play an important role in stablizing the intermediate by forming the oxyanion hole, which is observed in the structures of serine proteases.
The paper [3] proposed a plausible catalytic mechanism that consists of two stages, as follows;
The first stage is an acylation reaction of CSHase with the carbamoyl moiety, resulting in a cleavage of an NH3 molecule;
(1) the adjacent carboxyl group of Asp51 abstracts the proton of the -SH group of Cys177,
(2) the sulfur atom of Cys177 carries out a nucleophilic attack on the carbon atom of the carbonyl group,
(3) the NZ atom of Lys144 possibly stabilizes an acquired transient tetrahedral intermediate carrying an oxyanion near it,
(4) the proton held by Asp51 is then donated to the nitrogen atom of the susceptible C-N bond, which thus is cleaved and produces an ammonia molecule.
The second stage involves the deacylation of the acylated enzyme intermediate. A water molecule might take the place occupied ealier by the amine component of the substrate, followed by reactions similar to those at the first stage, with water substituting for the amine component:
(5) Asp51 draws a proton away from water,
(6) the resulting OH- ion attacks the carbonyl carbon atom of the acyl group that is attached to Cys177,
(7) a transient tetrahedral intermediate is formed, which is stabilized by Lys144, and
(8) Asp51 then donates the proton to the sulfur atom of Cys177, which then releases the acid component that may further decomposes into a sarcosine and CO2 molecule.
Moreover, although the sulfate is annotated as cofactor, it does not seem to be directly involved in catalysis.

Created Updated
2002-07-09 2009-02-26