EzCatDB: S00341

DB codeS00341
RLCP classification1.13.30100.49
CATH domainDomain 13.40.50.850Catalytic domain
E.C.3.5.1.59
CSA1nba
MACiEM0025


Enzyme Name
Swiss-protKEGG

P32400
Protein nameN-carbamoylsarcosine amidaseN-carbamoylsarcosine amidase
carbamoylsarcosine amidase
SynonymsEC 3.5.1.59
N-carbamoylsarcosine amidohydrolase
CSHase

KEGG pathways
MAP codePathways
MAP00330Arginine and proline metabolism

Swiss-prot:Accession NumberP32400
Entry nameCSH_ARTSP
ActivityN-carbamoylsarcosine + H(2)O = sarcosine + CO(2) + NH(3).
SubunitHomotetramer.
Subcellular location
CofactorBinds 1 sulfate ion per subunit.


CofactorsSubstratesProducts
KEGG-idC00059C01043C00001C00213C00011C00014
CompoundSulfateN-CarbamoylsarcosineH2OSarcosineCO2NH3
Typesulfate groupamino acids,amide group,amine groupH2Oamino acidsothersamine group,organic ion
1nbaABound:SO4Unbound
UnboundUnboundUnbound
1nbaBBound:SO4Unbound
UnboundUnboundUnbound
1nbaCBound:SO4Unbound
UnboundUnboundUnbound
1nbaDBound:SO4Unbound
UnboundUnboundUnbound

Active-site residues
resource
literature
pdbCatalytic residues
1nbaAALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177
1nbaBALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177
1nbaCALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177
1nbaDALA 172;THR 173(cis-peptide);ASP 51;LYS 144;CYS 177

References for Catalytic Mechanism
ReferencesSectionsNo. of steps in catalysis
[1]p.1128
[2]p.278-279
[3]p.256-2578
[4]Fig.65

references
[1]
CommentsX-ray crystallography (2.0 Angstroms)
PubMed ID1381445
JournalJ Mol Biol
Year1992
Volume226
Pages1111-30
AuthorsRomao MJ, Turk D, Gomis-Ruth FX, Huber R, Schumacher G, Mollering H, Russmann L
TitleCrystal structure analysis, refinement and enzymatic reaction mechanism of N-carbamoylsarcosine amidohydrolase from Arthrobacter sp. at 2.0 A resolution.
Related PDB1nba
[2]
CommentsX-ray crystallography (2.28 Angstroms)
Medline ID97070380
PubMed ID8913306
JournalJ Mol Biol
Year1996
Volume263
Pages269-83
AuthorsZajc A., Romao M.J., Turk D., Huber R
TitleCrystallographic and fluorescence studies of ligand binding to N-carbamoylsarcosine amidohydrolase from Arthrobacter sp.
[3]
PubMed ID11237598
JournalJ Mol Biol
Year2001
Volume306
Pages251-61
AuthorsWang WC, Hsu WH, Chien FT, Chen CY
TitleCrystal 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.
[4]
PubMed ID11714269
JournalBiochemistry
Year2001
Volume40
Pages14166-72
AuthorsDu X, Wang W, Kim R, Yakota H, Nguyen H, Kim SH
TitleCrystal structure and mechanism of catalysis of a pyrazinamidase from Pyrococcus horikoshii.

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.

createdupdated
2002-07-092009-02-26
Copyright: Nozomi Nagano, JST & CBRC-AIST
Funded by PRESTO/Japan Science and Technology Corporation (JST) (December 2001 - November 2004)
Funded by Grant-in-Aid for Publication of Scientific Research Results/Japan Society for the Promotion of Science (JSPS) (April 2005 - March 2006)
Funded by Grant-in-Aid for Scientific Research (B)/Japan Society for the Promotion of Science (JSPS) (April 2005 - March 2008)
Funded by BIRD/Japan Science and Technology Corporation (JST) (September 2005 - September 2010)
Funded by BIRD/Japan Science and Technology Corporation (JST) (October 2007 - September 2010)
Funded by Grant-in-Aid for Publication of Scientific Research Results/Japan Society for the Promotion of Science (JSPS) (April 2011 - March 2012)

© Computational Biology Research Center, AIST, 2004 All Rights Reserved.