DB code: S00466

RLCP classification 3.103.70020.355 : Transfer
CATH domain 3.90.550.10 : Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A Catalytic domain
E.C. 2.7.7.43
CSA
M-CSA
MACiE

CATH domain Related DB codes (homologues)
3.90.550.10 : Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A S00709 S00465 D00417 D00859 D00860 T00415

Uniprot Enzyme Name
UniprotKB Protein name Synonyms Pfam
P0A0Z8 N-acylneuraminate cytidylyltransferase
EC 2.7.7.43
CMP-N-acetylneuraminic acid synthetase
CMP-NeuNAc synthetase
CMP-sialic acid synthetase
PF02348 (CTP_transf_3)
[Graphical View]

KEGG enzyme name
N-acylneuraminate cytidylyltransferase
CMP-sialate pyrophosphorylase
CMP-sialate synthase
cytidine 5'-monophosphosialic acid synthetase
CMP-Neu5Ac synthetase
CMP-NeuAc synthetase
acylneuraminate cytidyltransferase
CMP-N-acetylneuraminate synthetase
CMP-N-acetylneuraminate synthase
CMP-N-acetylneuraminic acid synthase
CMP-NANA synthetase
CMP-sialate synthetase
CMP-sialic synthetase
cytidine 5'-monophospho-N-acetylneuraminic acid synthetase
cytidine 5-monophosphate N-acetylneuraminic acid synthetase
cytidine monophosphosialic acid synthetase
cytidine monophosphoacetylneuraminic synthetase
cytidine monophosphosialate pyrophosphorylase
cytidine monophosphosialate synthetase
acetylneuraminate cytidylyltransferase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P0A0Z8 NEUA_NEIME CTP + N-acylneuraminate = diphosphate + CMP-N- acylneuraminate. Cytoplasm.

KEGG Pathways
Map code Pathways E.C.
MAP00530 Aminosugars metabolism

Compound table
Cofactors Substrates Products Intermediates
KEGG-id C00305 C00063 C00591 C00013 C01064
E.C.
Compound Magnesium CTP N-Acylneuraminate Pyrophosphate CMP-N-acylneuraminate
Type divalent metal (Ca2+, Mg2+) amine group,nucleotide amide group,carbohydrate,carboxyl group phosphate group/phosphate ion amide group,amine group,carbohydrate,carboxyl group,nucleotide
ChEBI 18420
17677
29888
PubChem 888
6176
1023
21961011
1eyrA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Analogue:CDP Unbound Unbound Unbound
1eyrB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Analogue:CDP Unbound Unbound Unbound
1eziA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound
1eziB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain Unbound Unbound Unbound Unbound Unbound

Reference for Active-site residues
resource references E.C.
literature [9], [10]

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1eyrA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ARG 12;LYS 21;ASP 211 ASP 209;ASP 211(magnesium binding)
1eyrB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ARG 12;LYS 21;ASP 211 ASP 209;ASP 211(magnesium binding)
1eziA Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ARG 12;LYS 21;ASP 211 ASP 209;ASP 211(magnesium binding)
1eziB Pdbj logo s Rasmollogo id Rasmollogo chain Mmcif id Mmcif chain ARG 12;LYS 21;ASP 211 ASP 209;ASP 211(magnesium binding)

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[5]
Fig.5, p.779 1
[9]
p.8195-8196
[10]
Fig.9, p.152-153 1

References
[1]
Resource
Comments
Medline ID
PubMed ID 4620387
Journal Biochem Soc Symp
Year 1974
Volume (40)
Pages 87-116
Authors Schauer R, Buscher HP, Casals-Stenzel J
Title Sialic acids: their analysis and enzymic modification in relation to the synthesis of submandibular-gland glycoproteins.
Related PDB
Related UniProtKB
[2]
Resource
Comments
Medline ID
PubMed ID 2544267
Journal Carbohydr Res
Year 1989
Volume 186
Pages 326-34
Authors Petrie CR 3rd, Sharma M, Simmons OD, Korytnyk W
Title Synthesis of analogs of N-acetylneuraminic acid and their effect on CMP-sialate synthase.
Related PDB
Related UniProtKB
[3]
Resource
Comments
Medline ID
PubMed ID 2559792
Journal Carbohydr Res
Year 1989
Volume 194
Pages 49-61
Authors Christian R, Schreiner E, Zbiral E, Schulz G
Title The side-chain conformations of N-acetyl-7-,8-,9-deoxy-, and -4,7-dideoxy-neuraminic acid and their effect on the activation of CTP:N-acylneuraminic acid cytidylyltransferase.
Related PDB
Related UniProtKB
[4]
Resource
Comments
Medline ID
PubMed ID 2559791
Journal Carbohydr Res
Year 1989
Volume 194
Pages c15-8
Authors Zbiral E, Schreiner E, Christian R
Title Synthesis of the 4-acetamido-4-deoxy analogue of N-acetylneuraminic acid and its behaviour towards CMP-sialate synthase.
Related PDB
Related UniProtKB
[5]
Resource
Comments
Medline ID
PubMed ID 1731934
Journal Biochemistry
Year 1992
Volume 31
Pages 775-80
Authors Ambrose MG, Freese SJ, Reinhold MS, Warner TG, Vann WF
Title 13C NMR investigation of the anomeric specificity of CMP-N-acetylneuraminic acid synthetase from Escherichia coli.
Related PDB
Related UniProtKB
[6]
Resource
Comments
Medline ID
PubMed ID 7858974
Journal Bioorg Med Chem
Year 1994
Volume 2
Pages 669-74
Authors Lubineau A, Auge C, Gautheron-Le Narvor C, Ginet JC
Title Combined chemical and enzymatic synthesis of the sialylated non reducing terminal sequence of GM1b glycolylated ganglioside, a potential human tumor marker.
Related PDB
Related UniProtKB
[7]
Resource
Comments
Medline ID
PubMed ID 9702777
Journal Nat Biotechnol
Year 1998
Volume 16
Pages 769-72
Authors Gilbert M, Bayer R, Cunningham AM, DeFrees S, Gao Y, Watson DC, Young NM, Wakarchuk WW
Title The synthesis of sialylated oligosaccharides using a CMP-Neu5Ac synthetase/sialyltransferase fusion.
Related PDB
Related UniProtKB
[8]
Resource
Comments
Medline ID
PubMed ID 9702765
Journal Nat Biotechnol
Year 1998
Volume 16
Pages 720-1
Authors Warner TG
Title Sweet success with tethered enzyme catalysis.
Related PDB
Related UniProtKB
[9]
Resource
Comments X-ray crystallography
Medline ID
PubMed ID 11113120
Journal J Biol Chem
Year 2001
Volume 276
Pages 8190-6
Authors Mosimann SC, Gilbert M, Dombroswki D, To R, Wakarchuk W, Strynadka NC
Title Structure of a sialic acid-activating synthetase, CMP-acylneuraminate synthetase in the presence and absence of CDP.
Related PDB 1ezi 1eyr
Related UniProtKB
[10]
Resource
Comments Crystal structures of the homologous enzyme
Medline ID
PubMed ID 11545592
Journal J Mol Biol
Year 2001
Volume 312
Pages 143-55
Authors Jelakovic S, Schulz GE
Title The structure of CMP:2-keto-3-deoxy-manno-octonic acid synthetase and of its complexes with substrates and substrate analogs.
Related PDB 1h7e 1h7f 1h7g 1h7h 1h7t
Related UniProtKB
[11]
Resource
Comments
Medline ID
PubMed ID 12355462
Journal Biotechnol Bioeng
Year 2002
Volume 80
Pages 516-24
Authors Lee SG, Lee JO, Yi JK, Kim BG
Title Production of cytidine 5'-monophosphate N-acetylneuraminic acid using recombinant Escherichia coli as a biocatalyst.
Related PDB
Related UniProtKB
[12]
Resource
Comments
Medline ID
PubMed ID 11893746
Journal J Biol Chem
Year 2002
Volume 277
Pages 19688-96
Authors Munster AK, Weinhold B, Gotza B, Muhlenhoff M, Frosch M, Gerardy-Schahn R
Title Nuclear localization signal of murine CMP-Neu5Ac synthetase includes residues required for both nuclear targeting and enzymatic activity.
Related PDB
Related UniProtKB

Comments
According to the literature [9], O2 atom of the substrate, NeuAc, acts as a nucleophile, which makes an SN2 attack on the alpha-phosphate of the other substrate, CTP. During the catalysis, the leaving group, pyrophsophate, can be stabilized by Arg12, Lys21, and Mg2+, which seems to bridging the phosphoryl groups of CTP and the conserved residues, Asp209 and Asp211.
The literature [9] suggested that, although there is no candidate for the general base, which can activate the nucleophile, NeuAc O2 atom, an ordered water molecule might serve as the general base or a conformational rearrangement might bring a general base within hydrogen-bonding distance of the O2 atom upon the substrate. Meanwhile, another paper [10] on its homologous enzyme, CMP-Kdo synthease, suggested that a water molecule tightly bound to two aspartic acid residues, Asp98 and Asp225, would acts as the general base, which can activate the acceptor hydroxyl group. In fact, Asp211 of this enzyme, corresponds to Asp225 of the homologous enzyme, in terms of the relative position against the nucleotide substrate. Thus, Asp225 may play a role as a general base, which can activate the acceptor O2 atom, through a water molecule.
Moreover, the paper [9] also suggested that an ordered water molecule hydrogen-bonding to mainchain oxygen atom of Asn14 can donate a proton to the leaving group, pyrophosphate.
Taken together, the reaction proceeds as follows:
(1) Asp211 acts as a general base to activate O2 hydroxyl group, through water molecule.
(2) The activated O2 atom makes a nucleophilic attack on the alpha-phosphate of CTP. The reaction proceeds via SN2-like mechanism.
(3) Arg12 and Lys21 stabilize the leaving pyrophosphate, along with magnesium ion.

Created Updated
2003-07-17 2009-02-26