DB code: D00859

CATH domain -.-.-.- :
3.90.550.10 : Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A Catalytic domain
E.C. 2.4.1.-
CSA
M-CSA
MACiE

CATH domain Related DB codes (homologues)
3.90.550.10 : Spore Coat Polysaccharide Biosynthesis Protein SpsA; Chain A S00709 S00465 S00466 D00417 D00860 T00415

Uniprot Enzyme Name
UniprotKB Protein name Synonyms RefSeq CAZy Pfam
P27809 Glycolipid 2-alpha-mannosyltransferase
EC 2.4.1.-
Alpha-1,2-mannosyltransferase
NP_010771.1 (Protein)
NM_001180791.1 (DNA/RNA sequence)
GT15 (Glycosyltransferase Family 15)
PF01793 (Glyco_transf_15)
[Graphical View]

KEGG enzyme name
Glycolipid 2-alpha-mannosyltransferase
Guanosine diphosphomannose-oligosaccharide-lipid mannosyltransferase
GDP-mannose-oligosaccharide-lipid mannosyltransferase
Oligosaccharide-lipid mannosyltransferase
GDP-mannose:glycolipid 1,2-alpha-D-mannosyltransferase

UniprotKB: Accession Number Entry name Activity Subunit Subcellular location Cofactor
P27809 KRE2_YEAST Transfers an alpha-D-mannosyl residue from GDP-mannose into lipid-linked oligosaccharide, forming an alpha-1,2-D-mannosyl-D-mannose linkage. Golgi apparatus membrane, Single-pass type II membrane protein. Manganese.

KEGG Pathways
Map code Pathways E.C.

Compound table
Cofactors Substrates Products Intermediates
KEGG-id C00034 C00096 L00058 L00060 C00035 L00059 L00061
E.C.
Compound Manganese GDP-mannose Man2-Ser/Thr O-glycan (Man)n+9(GlcNAc)2-ASN N-glycan GDP Man3-Ser/Thr O-glycan (Man)2n+9(GlcNAc)2-ASN N-glycan
Type heavy metal amide group,amine group,carbohydrate,nucleotide peptide/protein,polysaccharide amide group,peptide/protein,polysaccharide amide group,amine group,nucleotide peptide/protein,polysaccharide amide group,peptide/protein,polysaccharide
ChEBI 18291
 35154
 18291
 35154
 		15820
 15820
 		17552
 17552
PubChem 23930
 23930
 		18396
 18396
 		8977
 8977
1s4nA00 Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1s4nB00 Unbound Unbound Unbound Unbound Unbound Unbound Unbound
1s4oA00 Bound:_MN Unbound Unbound Unbound Bound:GDP Unbound Unbound
1s4oB00 Bound:_MN Unbound Unbound Unbound Bound:GDP Unbound Unbound
1s4pA00 Bound:_MN Unbound Analogue:MMA Unbound Bound:GDP Unbound Unbound
1s4pB00 Bound:_MN Unbound Analogue:MMA Unbound Bound:GDP Unbound Unbound

Reference for Active-site residues
resource references E.C.
Literature [3]

Active-site residues
PDB Catalytic residues Cofactor-binding residues Modified residues Main-chain involved in catalysis Comment
1s4nA00 TYR 220 GLU 247;HIS 388(Manganese binding)
1s4nB00 TYR 220 GLU 247;HIS 388(Manganese binding)
1s4oA00 TYR 220 GLU 247;HIS 388(Manganese binding)
1s4oB00 TYR 220 GLU 247;HIS 388(Manganese binding)
1s4pA00 TYR 220 GLU 247;HIS 388(Manganese binding)
1s4pB00 TYR 220 GLU 247;HIS 388(Manganese binding)

References for Catalytic Mechanism
References Sections No. of steps in catalysis
[3]
Fig.5
[4]
p.59-60
[5]
Fig.10

References
[1]
Resource
Comments
Medline ID
PubMed ID 9182588
Journal J Biol Chem
Year 1997
Volume 272
Pages 15527-31
Authors Lussier M, Sdicu AM, Bussereau F, Jacquet M, Bussey H
Title The Ktr1p, Ktr3p, and Kre2p/Mnt1p mannosyltransferases participate in the elaboration of yeast O- and N-linked carbohydrate chains.
Related PDB
Related UniProtKB
[2]
Resource
Comments
Medline ID
PubMed ID 9878809
Journal Biochim Biophys Acta
Year 1999
Volume 1426
Pages 323-34
Authors Lussier M, Sdicu AM, Bussey H
Title The KTR and MNN1 mannosyltransferase families of Saccharomyces cerevisiae.
Related PDB
Related UniProtKB
[3]
Resource
Comments
Medline ID
PubMed ID 14752117
Journal J Biol Chem
Year 2004
Volume 279
Pages 17921-31
Authors Lobsanov YD, Romero PA, Sleno B, Yu B, Yip P, Herscovics A, Howell PL
Title Structure of Kre2p/Mnt1p: a yeast alpha1,2-mannosyltransferase involved in mannoprotein biosynthesis.
Related PDB 1s4n 1s4o 1s4p
Related UniProtKB P27809
[4]
Resource
Comments
Medline ID
PubMed ID 15653326
Journal Trends Biochem Sci
Year 2005
Volume 30
Pages 53-62
Authors Qasba PK, Ramakrishnan B, Boeggeman E
Title Substrate-induced conformational changes in glycosyltransferases.
Related PDB
Related UniProtKB
[5]
Resource
Comments
Medline ID
PubMed ID 18518825
Journal Annu Rev Biochem
Year 2008
Volume 77
Pages 521-55
Authors Lairson LL, Henrissat B, Davies GJ, Withers SG
Title Glycosyltransferases: structures, functions, and mechanisms.
Related PDB
Related UniProtKB

Comments
Previously, this enzyme was categorized in EC 2.4.1.131, but transferred to EC 2.4.1.-.
This enzyme belongs to glycosyltransferase family-15 (GT15 family), with a GT-A fold and a retaining mechanism (see [5]).
The structure of the N-terminal domain, which contains the N-terminal cytoplasmic region and a membrane-bound region, has not been determined yet.
According to the literature [3], [4] and [5], two possible reaction mechanisms have been proposed for this enzyme: A double displacement mechanism and a substitution nucleophilic internal (SNi)-like mechanism. To date, it has not been elucidated which mechanism is more appropriate.
In the double displacement mechanism, GDP-mannose is first transferred to a nucleophilic residue, Tyr220 in this enzyme, with an inversion of the configuration at C1 atom, and is then transferred to the acceptor mannose with the C1 atom reverting to its original configuration.
In the SNi-like mechanism, an oxocarbenium ion-like transition state/intermediate is formed from GDP-mannose, and the mannose group is attached on the same side by the acceptor mannose.

Created Updated
2010-08-18 2011-10-04