Q9FX21 · STT3B_ARATH
- ProteinDolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B
- GeneSTT3B
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids735 (go to sequence)
- Protein existenceEvidence at transcript level
- Annotation score5/5
Function
function
Catalytic subunit of the oligosaccharyl transferase (OST) complex that catalyzes the initial transfer of a defined glycan (Glc3Man9GlcNAc2 in eukaryotes) from the lipid carrier dolichol-pyrophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains, the first step in protein N-glycosylation. N-glycosylation occurs cotranslationally and the complex associates with the Sec61 complex at the channel-forming translocon complex that mediates protein translocation across the endoplasmic reticulum (ER). All subunits are required for a maximal enzyme activity. This subunit contains the active site and the acceptor peptide and donor lipid-linked oligosaccharide (LLO) binding pockets.
Catalytic activity
- a di-trans,poly-cis-dolichyl diphosphooligosaccharide + L-asparaginyl-[protein] = N4-(oligosaccharide-(1->4)-N-acetyl-beta-D-glucosaminyl-(1->4)-N-acetyl-beta-D-glucosaminyl)-L-asparaginyl-[protein] + a di-trans,poly-cis-dolichyl diphosphate + H+
a di-trans,poly-cis-dolichyl diphosphooligosaccharide RHEA-COMP:19509 + RHEA-COMP:12804 = RHEA-COMP:12805 + a di-trans,poly-cis-dolichyl diphosphate RHEA-COMP:19506 + CHEBI:15378
Cofactor
Mn2+ (UniProtKB | Rhea| CHEBI:29035 )
Pathway
Protein modification; protein glycosylation.
Features
Showing features for binding site, site.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Binding site | 72 | Mn2+ (UniProtKB | ChEBI) | |||
Site | 72 | Interacts with target acceptor peptide in protein substrate | |||
Site | 183 | Important for catalytic activity | |||
Binding site | 190 | Mn2+ (UniProtKB | ChEBI) | |||
Binding site | 192 | Mn2+ (UniProtKB | ChEBI) | |||
Site | 375 | Interacts with target acceptor peptide in protein substrate | |||
Binding site | 429 | dolichyl diphosphooligosaccharide (UniProtKB | ChEBI) | |||
Binding site | 567 | dolichyl diphosphooligosaccharide (UniProtKB | ChEBI) | |||
Site | 632 | Interacts with target acceptor peptide in protein substrate | |||
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | endoplasmic reticulum | |
Cellular Component | endoplasmic reticulum membrane | |
Cellular Component | nucleus | |
Molecular Function | dolichyl-diphosphooligosaccharide-protein glycotransferase activity | |
Molecular Function | metal ion binding | |
Biological Process | protein glycosylation |
Keywords
- Molecular function
- Ligand
Enzyme and pathway databases
Protein family/group databases
Names & Taxonomy
Protein names
- Recommended nameDolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B
- EC number
- Short namesOligosaccharyl transferase subunit STT3B; STT3-B
- Alternative names
Gene names
Organism names
- Strain
- Taxonomic lineageEukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > eudicotyledons > Gunneridae > Pentapetalae > rosids > malvids > Brassicales > Brassicaceae > Camelineae > Arabidopsis
Accessions
- Primary accessionQ9FX21
- Secondary accessions
Proteomes
Organism-specific databases
Genome annotation databases
Subcellular Location
UniProt Annotation
GO Annotation
Endoplasmic reticulum membrane ; Multi-pass membrane protein
Features
Showing features for topological domain, transmembrane.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Topological domain | 1-38 | Cytoplasmic | |||
Transmembrane | 39-59 | Helical | |||
Topological domain | 60-142 | Lumenal | |||
Transmembrane | 143-161 | Helical | |||
Topological domain | 162-163 | Cytoplasmic | |||
Transmembrane | 164-181 | Helical | |||
Topological domain | 182-192 | Lumenal | |||
Transmembrane | 193-212 | Helical | |||
Topological domain | 213-214 | Cytoplasmic | |||
Transmembrane | 215-229 | Helical | |||
Topological domain | 230-234 | Lumenal | |||
Transmembrane | 235-251 | Helical | |||
Topological domain | 252-256 | Cytoplasmic | |||
Transmembrane | 257-282 | Helical | |||
Topological domain | 283-290 | Lumenal | |||
Transmembrane | 291-310 | Helical | |||
Topological domain | 311-326 | Cytoplasmic | |||
Transmembrane | 327-347 | Helical | |||
Topological domain | 348-380 | Lumenal | |||
Transmembrane | 381-403 | Helical | |||
Topological domain | 404-409 | Cytoplasmic | |||
Transmembrane | 410-426 | Helical | |||
Topological domain | 427-430 | Lumenal | |||
Transmembrane | 431-452 | Helical | |||
Topological domain | 453-494 | Cytoplasmic | |||
Transmembrane | 495-515 | Helical | |||
Topological domain | 516-735 | Lumenal | |||
Keywords
- Cellular component
Phenotypes & Variants
Disruption phenotype
No visible phenotype.
Variants
We now provide the "Disease & Variants" viewer in its own tab.
The viewer provides 40 variants from UniProt as well as other sources including ClinVar and dbSNP.
PTM/Processing
Features
Showing features for chain, glycosylation.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Chain | PRO_0000420537 | 1-735 | Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B | ||
Glycosylation | 574 | N-linked (GlcNAc...) asparagine | |||
Glycosylation | 581 | N-linked (GlcNAc...) asparagine | |||
Glycosylation | 585 | N-linked (GlcNAc...) (high mannose) asparagine | |||
Keywords
- PTM
Proteomic databases
PTM databases
Expression
Tissue specificity
Expressed preferentially in the root but also in the shoot.
Gene expression databases
Interaction
Subunit
Component of the oligosaccharyltransferase (OST) complex.
Protein-protein interaction databases
Structure
Family & Domains
Features
Showing features for motif, region.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Motif | 70-72 | DXD motif 1 | |||
Motif | 190-192 | DXD motif 2 | |||
Motif | 372-375 | SVSE motif | |||
Region | 562-564 | Interacts with target acceptor peptide in protein substrate | |||
Motif | 562-566 | WWDYG motif | |||
Motif | 629-636 | DK motif | |||
Domain
Despite low primary sequence conservation between eukaryotic catalytic subunits and bacterial and archaeal single subunit OSTs (ssOST), structural comparison revealed several common motifs at spatially equivalent positions, like the DXD motif 1 on the external loop 1 and the DXD motif 2 on the external loop 2 involved in binding of the metal ion cofactor and the carboxamide group of the acceptor asparagine, the conserved Glu residue of the TIXE/SVSE motif on the external loop 5 involved in catalysis, as well as the WWDYG and the DK/MI motifs in the globular domain that define the binding pocket for the +2 Ser/Thr of the acceptor sequon. In bacterial ssOSTs, an Arg residue was found to interact with a negatively charged side chain at the -2 position of the sequon. This Arg is conserved in bacterial enzymes and correlates with an extended sequon requirement (Asp-X-Asn-X-Ser/Thr) for bacterial N-glycosylation.
Sequence similarities
Belongs to the STT3 family.
Keywords
- Domain
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length735
- Mass (Da)82,980
- Last updated2001-03-01 v1
- MD5 Checksum741C6938C508613594B64544AF594819
Sequence caution
Features
Showing features for sequence conflict.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Sequence conflict | 595 | in Ref. 3; BX816490 | |||
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AC015446 EMBL· GenBank· DDBJ | AAG12524.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
CP002684 EMBL· GenBank· DDBJ | AEE31675.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
BX816490 EMBL· GenBank· DDBJ | - | mRNA | No translation available. | |
AK229582 EMBL· GenBank· DDBJ | BAF01432.1 EMBL· GenBank· DDBJ | mRNA |