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Information on EC 2.4.99.18 - dolichyl-diphosphooligosaccharide-protein glycotransferase and Organism(s) Homo sapiens
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2.4.99.18 dolichyl-diphosphooligosaccharide-protein glycotransferaseIUBMB Comments
Occurs in eukaryotes that form a glycoprotein by the transfer of a glucosyl-mannosyl-glucosamine polysaccharide to the side-chain of an L-asparagine residue in the sequence -Asn-Xaa-Ser- or -Asn-Xaa-Thr- (Xaa not Pro) in nascent polypeptide chains. The basic oligosaccharide is the tetradecasaccharide Glc3Man9GlcNAc2 (for diagram {polysacc/Dol14}). However, smaller oligosaccharides derived from it and oligosaccharides with additional monosaccharide units attached may be involved. See ref for a review of N-glycoproteins in eukaryotes. Man3GlcNAc2 seems to be common for all of the oligosaccharides involved with the terminal N-acetylglucosamine linked to the protein L-asparagine. Occurs on the cytosolic face of the endoplasmic reticulum. The dolichol involved normally has 14-21 isoprenoid units with two trans double-bonds at the omega end, and the rest of the double-bonds in cis form.
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Word Map
- 2.4.99.18
-
n-glycosylation
-
n-linked
- glycans
-
lipid-linked
-
sequons
-
asparagine-linked
- jejuni
- campylobacter
- dolichol
-
ribophorins
- otase
-
cotranslational
-
bloc
-
dolichol-linked
-
translocon
- glc3man9glcnac2
- heptasaccharide
-
s-layer
-
underglycosylation
-
preassembled
-
mannosyltransferases
-
glycoengineering
-
hypoglycosylation
-
hetero-oligomeric
-
single-subunit
-
translocon-associated
- man9glcnac2
- lari
- drug development
- biotechnology
- medicine
- n-glycoproteins
-
glycoproteomics
- pilins
The taxonomic range for the selected organisms is: Homo sapiens
The expected taxonomic range for this enzyme is: Eukaryota, Archaea, Bacteria
The expected taxonomic range for this enzyme is: Eukaryota, Archaea, Bacteria
Reaction Schemes
Synonyms
oligosaccharyltransferase, oligosaccharyl transferase, oligosaccharyltransferase complex, ost3p, wbp1p, ost6p, oligosaccharide transferase, swp1p, tbstt3a, tbstt3b, 
more
topSYNONYM 
ORGANISM
UNIPROT
COMMENTARY 
LITERATURE
asparagine N-glycosyltransferase
-
-
-
-
dolichyldiphosphooligosaccharide-protein oligosaccharyltransferase
-
-
-
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glycosyltransferase, dolichyldiphosphooligosaccharide-protein
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-
-
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glycosyltransferase, dolichylpyrophosphodiacetylchitobiose-protein
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-
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oligomannosyltransferase
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-
-
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oligosaccharide transferase
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-
-
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oligosaccharyltransferase, dolichyldiphosphoryloligosaccharide-protein
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-
-
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OST
OST
-
-
-
-
REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
hexosyl group transfer
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-
-
-
SYSTEMATIC NAME
IUBMB Comments
dolichyl-diphosphooligosaccharide:protein-L-asparagine N-beta-D-oligopolysaccharidotransferase
Occurs in eukaryotes that form a glycoprotein by the transfer of a glucosyl-mannosyl-glucosamine polysaccharide to the side-chain of an L-asparagine residue in the sequence -Asn-Xaa-Ser- or -Asn-Xaa-Thr- (Xaa not Pro) in nascent polypeptide chains. The basic oligosaccharide is the tetradecasaccharide Glc3Man9GlcNAc2 (for diagram {polysacc/Dol14}). However, smaller oligosaccharides derived from it and oligosaccharides with additional monosaccharide units attached may be involved. See ref [2] for a review of N-glycoproteins in eukaryotes. Man3GlcNAc2 seems to be common for all of the oligosaccharides involved with the terminal N-acetylglucosamine linked to the protein L-asparagine. Occurs on the cytosolic face of the endoplasmic reticulum. The dolichol involved normally has 14-21 isoprenoid units with two trans double-bonds at the omega end, and the rest of the double-bonds in cis form.
CAS REGISTRY NUMBER
COMMENTARY
75302-32-8
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SUBSTRATE
PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
dolichyl diphosphooligosaccharide + protein L-asparagine
dolichyl diphosphate + a glycoprotein with the oligosaccharide chain attached by N-glycosyl linkage to protein L-asparagine
-
ribophorin I can regulate the delivery of precursor proteins to the oligosaccharyltransferase complex by capturing substrates and presenting them to the catalytic core
-
-
?
dolichyl diphosphooligosaccharide + protein L-asparagine
dolichyl diphosphate + glycoprotein with the oligosaccharide chain attached by N-glycosyl-linkage to protein L-asparagine
dolichyl diphosphooligosaccharide + [protein]-L-asparagine
dolichyl diphosphate + [protein]-L-asparagine-N-oligosaccharide
dolichyl diphosphooligosaccharide + protein L-asparagine
dolichyl diphosphate + glycoprotein with the oligosaccharide chain attached by N-glycosyl-linkage to protein L-asparagine
-
-
-
?
dolichyl diphosphooligosaccharide + protein L-asparagine
dolichyl diphosphate + glycoprotein with the oligosaccharide chain attached by N-glycosyl-linkage to protein L-asparagine
-
-
-
?
dolichyl diphosphooligosaccharide + [protein]-L-asparagine
dolichyl diphosphate + [protein]-L-asparagine-N-oligosaccharide
-
-
a glycoprotein with the oligosaccharide chain attached by N-beta-D-glycosyl linkage to a protein L-asparagine
-
?
dolichyl diphosphooligosaccharide + [protein]-L-asparagine
dolichyl diphosphate + [protein]-L-asparagine-N-oligosaccharide
-
transfer of a preassembled, uniform oligosaccharide (Glc3Man9GlcNAc2 in most eukaryotes) from the isoprenoid lipid carrier dolichol pyrophosphate to the side-chain amide group nitrogen of an asparagine residue contained in a N-X-S(T) sequon of the polypeptide substrate, where X can be any amino acid except proline, mechanism, modeling, overview
a glycoprotein with the oligosaccharide chain attached by N-beta-D-glycosyl linkage to a protein L-asparagine
-
?
additional information
?
-
-
fine regulation of OTase activity is essential for normal cognitive-function development
-
-
?
NATURAL SUBSTRATE
NATURAL PRODUCT
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate)
(Substrate)
LITERATURE
(Substrate)
(Substrate)
COMMENTARY
(Product)
(Product)
LITERATURE
(Product)
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
r=reversible
ir=irreversible
?=not specified
dolichyl diphosphooligosaccharide + [protein]-L-asparagine
dolichyl diphosphate + [protein]-L-asparagine-N-oligosaccharide
additional information
?
-
-
fine regulation of OTase activity is essential for normal cognitive-function development
-
-
?
dolichyl diphosphooligosaccharide + [protein]-L-asparagine
dolichyl diphosphate + [protein]-L-asparagine-N-oligosaccharide
-
-
a glycoprotein with the oligosaccharide chain attached by N-beta-D-glycosyl linkage to a protein L-asparagine
-
?
dolichyl diphosphooligosaccharide + [protein]-L-asparagine
dolichyl diphosphate + [protein]-L-asparagine-N-oligosaccharide
-
transfer of a preassembled, uniform oligosaccharide (Glc3Man9GlcNAc2 in most eukaryotes) from the isoprenoid lipid carrier dolichol pyrophosphate to the side-chain amide group nitrogen of an asparagine residue contained in a N-X-S(T) sequon of the polypeptide substrate, where X can be any amino acid except proline, mechanism, modeling, overview
a glycoprotein with the oligosaccharide chain attached by N-beta-D-glycosyl linkage to a protein L-asparagine
-
?
INHIBITOR
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
ACTIVATING COMPOUND
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
IMAGE
SPECIFIC ACTIVITY [µmol/min/mg]
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
ORGANISM
COMMENTARY
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
oligosaccharyltransferase A complex (catalytic subunit). P46977: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit STT3A. P0C6T2: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit 4, P61165: transmembrane protein 258, P61803: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit DAD1, P04843: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit 1, P04844: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit 2, P39656: dolichyl-diphosphooligosaccharide-protein glycosyltransferase 48 kDa subunit, Q9NRP0: oligosaccharyltransferase complex subunit OSTC
P46977; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
SwissProt
oligosaccharyltransferase B complex. Q8TCJ2: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit STT3B (catalytic subunit). P0C6T2: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit 4, P61165: transmembrane protein 258, P61803: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit DAD1, P04843: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit 1, P04844: dolichyl-diphosphooligosaccharide-protein glycosyltransferase subunit 2, P39656: dolichyl-diphosphooligosaccharide-protein glycosyltransferase 48 kDa subunit, Q9NRP0: oligosaccharyltransferase complex subunit OSTC
Q8TCJ2; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
SwissProt
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY
GeneOntology No.
LITERATURE
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
evolution
-
OST is a heterooligomeric membrane protein complex in animals, plants, and fungi. In bacteria, archaea, and protozoa, OST is a monomer
malfunction
metabolism
-
in the central reaction of the N-linked glycosylation pathway, one of the most abundant modifications of proteins in eukaryotes, oligosaccharyltransferase, a multimeric complex located at the membrane of the endoplasmic reticulum, transfers a preassembled oligosaccharide to selected asparagine residues within the consensus sequence asparagine-X-serine/threonine
physiological function
additional information
-
OST complexes containing Stt3-B are more active than OST complexes harboring Stt3-A. Stt3-A and Stt3-B also differ in their acceptor substrate selectivity
malfunction
-
mutations affecting the biosynthesis of the activated Glc3Man9GlcNAc2 oligosaccharide substrate or the biogenesis of OSTs generally have a systemic effect in eukaryotes and alter glycosylation of many different glycoproteins. It is the substrate specificity of OST that translates defects in the biosynthesis of the oligosaccharide substrate into a generalized and multisystemic deficiency observed for the different forms of human congenital disorders of glycosylation type I. Mutations in the subunit paralogues N33/Tusc3 and IAP do not yield the pleiotropic phenotypes typical for CDG type I but specifically result in nonsyndromic mental retardation
malfunction
P46977; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0, Q8TCJ2; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
defects in N-linked glycosylation results in a class of inherited diseases known as congenital disorders of glycosylation
physiological function
-
the catalytic subunit of the eukaryotic OST and catalyzes the transfer of a highly defined, lipid-linked oligosaccharide (LLO) donor substrate to a multitude of peptide acceptor sequences located in different substrate proteins. The Stt3 subunit of OST harbors the catalytic center of the enzyme, and some components of the OST complex are involved in the recognition and utilization of glycosylation sites in specific glycoproteins. The oxidoreductase activity of subunits N33/Tusc3 and IAP is required for glycosylation of a subset of proteins essential for brain development
physiological function
P46977; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0, Q8TCJ2; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
asparagine-linked glycosylation (N-linked glycosylation) is an essential and highly conserved post-translational protein modification. This modification is essential for specific molecular recognition, protein folding, sorting in the endoplasmic reticulum, cell-cell communication, and stability. In humans and other mammals, the oligosaccharyltransferase (OST) complex has diverged into two distinct isoforms known as OST-A and OST-B that perform distinctly different roles in N-linked glycosylation of proteins. OST-A is connected directly to the translocation channel called Sec61 in the ER membrane and scans the newly synthesized unfolded polypeptide chain emerging from the ribosome for glycosylation sites. Therefore, OST-A is responsible for the majority of N-linked glycosylation in mammals. OST-B seems to act in a proofreading role to catch glycosylation sites that OST-A misses for partially folded proteins or proteins that contain disulfide bonds
physiological function
P46977; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0, Q8TCJ2; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
oligosaccharyltransferase (OST) catalyzes the transfer of a high-mannose glycan onto secretory proteins in the endoplasmic reticulum. Mammals express two distinct oligosaccharyltransferase complexes that act in a cotranslational (OST-A) or posttranslocational (OST-B) manner. The distinct functions of the two human complexes are based on structural differences of their catalytic subunits STT3A and STT3B, which result in interactions with distinct subunits and different affinities for acceptor peptides
UNIPROT
ENTRY NAME
ORGANISM
NO. OF AA
NO. OF TRANSM. HELICES
MOLECULAR WEIGHT[Da]
SOURCE
SEQUENCE
LOCALIZATION PREDICTION
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable).
The reliability class of the localization prediction ranges from 1 (very reliable) to 5 (not reliable). STT3B_HUMAN
826
10
93674
Swiss-Prot
other Location (Reliability: 2)
STT3A_HUMAN
705
12
80530
Swiss-Prot
Secretory Pathway (Reliability: 3)
E9PI32_HUMAN
119
2
14116
TrEMBL
Secretory Pathway (Reliability: 3)
A0A0C4DH80_HUMAN
102
2
12046
TrEMBL
Secretory Pathway (Reliability: 3)
E9PN73_HUMAN
117
2
13855
TrEMBL
Secretory Pathway (Reliability: 3)
H0YET6_HUMAN
194
2
21556
TrEMBL
Secretory Pathway (Reliability: 2)
A0A024R3J7_HUMAN
703
12
80428
TrEMBL
Secretory Pathway (Reliability: 3)
PDB
SCOP
CATH
UNIPROT
ORGANISM
SUBUNIT
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
heptamer
additional information
heptamer
-
the heptameric human OST complex contains the subunits ribophorin I (OST1p), ribophorin II (Swp1p), OST48 (Wbp1p), OST4 (OST4), Stt3-A/Stt3-B (Stt3p), N33/Tusc3 and IAP (OST3p and OST6p), and DAD1 (OST2p), struccture-function relationships, Stt3 proteins are the catalytic subunits of eukaryotic OST complexes, detailed overview. Human OST4 contains a very short luminal segment with one transmembrane span followed by a cytoplasmic part consisting of approximately ten residues
heptamer
-
the human Ost4 protein contains 37 amino acids, i.e. MITDVQLAIFANMLGVSLFLLVVLYHYVAVNNPKKQE, Ost4 is a small membrane protein and belongs to one of the seven subunits of human OST, structure analysis by NMR spectroscopy, residues 5-30 adopt an alpha-helical structure, and a kink structure in the transmembrane domain may be important for its function, overview
additional information
-
after SDS-PAGE the most active fractions contain four predominant protein bands with apparent molecular weight in the 50000 Da to 65000 Da range. N-terminal sequence analysis identifies the protein as ribophorin I, ribophorin II, and a 50000 Da homologue of Wbp1, a yeast protein essential for N-glycosylation
additional information
-
subunit STT3-A and SST3-B are both expressed in skin fibroblasts
additional information
P46977; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
the eukaryotic oligosaccharyltransferase is a complex of multiple non-identical subunits. The human oligosaccharyltransferase complex is formed with either STT3A or STT3B, two paralogues of Stt3. Human oligosaccharyltransferase complexes, OST-A (with STT3A) and OST-B (containing STT3B)
additional information
Q8TCJ2; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
the eukaryotic oligosaccharyltransferase is a complex of multiple non-identical subunits. The human oligosaccharyltransferase complex is formed with either STT3A or STT3B, two paralogues of Stt3. Human oligosaccharyltransferase complexes, OST-A (with STT3A) and OST-B (containing STT3B)
additional information
-
the eukaryotic oligosaccharyltransferase is a complex of multiple non-identical subunits. The human oligosaccharyltransferase complex is formed with either STT3A or STT3B, two paralogues of Stt3. Human oligosaccharyltransferase complexes, OST-A (with STT3A) and OST-B (containing STT3B)
PROTEIN VARIANTS
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
G374D
-
the missense mutation lies in the second half of the N-terminal luminal domain of ribophorin II subunit, the affected patient presents a fairly mild clinical phenotype, no clear genotype-phenotype correlation for this mutation
TEMPERATURE STABILITY
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
PURIFICATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
APPLICATION
ORGANISM
UNIPROT
COMMENTARY
LITERATURE
drug development
P46977; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0, Q8TCJ2; P0C6T2; P61165; P61803; P04843; P04844; P39656; Q9NRP0
cryoelectron microscopy structures of human oligosaccharyltransferase complexes OST-A and OST-B provide a basis for the design of inhibitors of N-glycosylation that modulate the maturation and activation of protein markers involved in tumor formation
medicine
-
mutation in OTase subunits are responsible for isolated cognitive deficit
REF.
AUTHORS
TITLE
JOURNAL
VOL.
PAGES
YEAR
ORGANISM (UNIPROT)
PUBMED ID
SOURCE
Kumar, V.; Heinemann, F.S.; Ozols, J.
Interleukin-2 induces N-glycosylation in T-cells: characterization of human lymphocyte oligosaccharyltransferase
Biochem. Biophys. Res. Commun.
247
524-529
1998
Homo sapiens
Knauer, R.; Lehle, L.
The oligosaccharyltransferase complex from yeast
Biochim. Biophys. Acta
1426
259-273
1999
Canis lupus familiaris, Gallus gallus, Homo sapiens, Sus scrofa, Saccharomyces cerevisiae (P48439), Saccharomyces cerevisiae
Kelleher, D.J.; Karaoglu, D.; Mandon, E.C.; Gilmore, R.
Oligosaccharyltransferase isoforms that contain different catalytic STT3 subunits have distinct enzymatic properties
Mol. Cell
12
101-111
2003
Canis lupus familiaris, Homo sapiens, Mus musculus
Molinari, F.; Foulquier, F.; Tarpey, P.S.; Morelle, W.; Boissel, S.; Teague, J.; Edkins, S.; Futreal, P.A.; Stratton, M.R.; Turner, G.; Matthijs, G.; Gecz, J.; Munnich, A.; Colleaux, L.
Oligosaccharyltransferase-subunit mutations in nonsyndromic mental retardation
Am. J. Hum. Genet.
82
1150-1157
2008
Homo sapiens
Wilson, C.M.; Roebuck, Q.; High, S.
Ribophorin I regulates substrate delivery to the oligosaccharyltransferase core
Proc. Natl. Acad. Sci. USA
105
9534-9539
2008
Homo sapiens
Gayen, S.; Kang, C.
Solution structure of a human minimembrane protein Ost4, a subunit of the oligosaccharyltransferase complex
Biochem. Biophys. Res. Commun.
409
572-576
2011
Homo sapiens
Mohorko, E.; Glockshuber, R.; Aebi, M.
Oligosaccharyltransferase: the central enzyme of N-linked protein glycosylation
J. Inherit. Metab. Dis.
34
869-878
2011
Saccharomyces cerevisiae, Canis lupus familiaris, Homo sapiens
Mohanty, S.; Chaudhary, B.P.; Zoetewey, D.
Structural insight into the mechanism of N-linked glycosylation by oligosaccharyltransferase
Biomolecules
10
624
2020
Homo sapiens (P46977 AND P0C6T2 AND P61165 AND P61803 AND P04843 AND P04844 AND P39656 AND Q9NRP0), Homo sapiens (Q8TCJ2 AND P0C6T2 AND P61165 AND P61803 AND P04843 AND P04844 AND P39656 AND Q9NRP0), Homo sapiens, Saccharomyces cerevisiae (P41543 AND P46964 AND P48439 AND Q99380 AND Q92316 AND P39007 AND P33767 AND Q02795), Saccharomyces cerevisiae, Saccharomyces cerevisiae ATCC 204508 (P41543 AND P46964 AND P48439 AND Q99380 AND Q92316 AND P39007 AND P33767 AND Q02795)
Ramirez, A.S.; Kowal, J.; Locher, K.P.
Cryo-electron microscopy structures of human oligosaccharyltransferase complexes OST-A and OST-B
Science
366
1372-1375
2019
Homo sapiens (P46977 AND P0C6T2 AND P61165 AND P61803 AND P04843 AND P04844 AND P39656 AND Q9NRP0), Homo sapiens (Q8TCJ2 AND P0C6T2 AND P61165 AND P61803 AND P04843 AND P04844 AND P39656 AND Q9NRP0), Homo sapiens
EXTERNAL LINKS (specific for EC-Number 2.4.99.18)
Transporter Classification Database (TCDB): 9.B.142.3.17, 9.B.142.3.14, 9.B.142.3.4, 9.B.142.3.5, 9.B.142.3.3
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