Q9FX21 · STT3B_ARATH

  • Protein
    Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B
  • Gene
    STT3B
  • Status
    UniProtKB reviewed (Swiss-Prot)
  • Amino acids
  • Protein existence
    Evidence at transcript level
  • Annotation score
    5/5

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

Cofactor

Mg2+ (UniProtKB | Rhea| CHEBI:18420 )

Mn2+ (UniProtKB | Rhea| CHEBI:29035 )

Pathway

Protein modification; protein glycosylation.

Features

Showing features for binding site, site.

Type
IDPosition(s)Description
Binding site72Mn2+ (UniProtKB | ChEBI)
Site72Interacts with target acceptor peptide in protein substrate
Site183Important for catalytic activity
Binding site190Mn2+ (UniProtKB | ChEBI)
Binding site192Mn2+ (UniProtKB | ChEBI)
Site375Interacts with target acceptor peptide in protein substrate
Binding site429dolichyl diphosphooligosaccharide (UniProtKB | ChEBI)
Binding site567dolichyl diphosphooligosaccharide (UniProtKB | ChEBI)
Site632Interacts with target acceptor peptide in protein substrate

GO annotations

AspectTerm
Cellular Componentendoplasmic reticulum
Cellular Componentendoplasmic reticulum membrane
Cellular Componentnucleus
Molecular Functiondolichyl-diphosphooligosaccharide-protein glycotransferase activity
Molecular Functionmetal ion binding
Biological Processprotein glycosylation

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B
  • EC number
  • Short names
    Oligosaccharyl transferase subunit STT3B; STT3-B
  • Alternative names
    • Protein STAUROSPORIN AND TEMPERATURE SENSITIVE 3-LIKE B

Gene names

    • Name
      STT3B
    • ORF names
      F12G12.5
    • Ordered locus names
      At1g34130

Organism names

  • Taxonomic identifier
  • Strain
    • cv. Columbia
  • Taxonomic lineage
    Eukaryota > Viridiplantae > Streptophyta > Embryophyta > Tracheophyta > Spermatophyta > Magnoliopsida > eudicotyledons > Gunneridae > Pentapetalae > rosids > malvids > Brassicales > Brassicaceae > Camelineae > Arabidopsis

Accessions

  • Primary accession
    Q9FX21
  • Secondary accessions
    • Q0WN68

Proteomes

Organism-specific databases

Genome annotation databases

Subcellular Location

Features

Showing features for topological domain, transmembrane.

Type
IDPosition(s)Description
Topological domain1-38Cytoplasmic
Transmembrane39-59Helical
Topological domain60-142Lumenal
Transmembrane143-161Helical
Topological domain162-163Cytoplasmic
Transmembrane164-181Helical
Topological domain182-192Lumenal
Transmembrane193-212Helical
Topological domain213-214Cytoplasmic
Transmembrane215-229Helical
Topological domain230-234Lumenal
Transmembrane235-251Helical
Topological domain252-256Cytoplasmic
Transmembrane257-282Helical
Topological domain283-290Lumenal
Transmembrane291-310Helical
Topological domain311-326Cytoplasmic
Transmembrane327-347Helical
Topological domain348-380Lumenal
Transmembrane381-403Helical
Topological domain404-409Cytoplasmic
Transmembrane410-426Helical
Topological domain427-430Lumenal
Transmembrane431-452Helical
Topological domain453-494Cytoplasmic
Transmembrane495-515Helical
Topological domain516-735Lumenal

Keywords

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.

Go to variant viewer

PTM/Processing

Features

Showing features for chain, glycosylation.

Type
IDPosition(s)Description
ChainPRO_00004205371-735Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit STT3B
Glycosylation574N-linked (GlcNAc...) asparagine
Glycosylation581N-linked (GlcNAc...) asparagine
Glycosylation585N-linked (GlcNAc...) (high mannose) asparagine

Keywords

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
IDPosition(s)Description
Motif70-72DXD motif 1
Motif190-192DXD motif 2
Motif372-375SVSE motif
Region562-564Interacts with target acceptor peptide in protein substrate
Motif562-566WWDYG motif
Motif629-636DK 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

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    735
  • Mass (Da)
    82,980
  • Last updated
    2001-03-01 v1
  • MD5 Checksum
    741C6938C508613594B64544AF594819
MGGKSEPAKSESMATKPDLLNTSFFSFKSLKLKTKQQELLLRISILGLVYILAFIARLFSVLRYESMIHEFDPYFNYRTTLFLTEKGFYEFWNWFDSESWYPLGRIIGGTLYPGLMVTAALIYWTLRFLRFFVHIREVCVLTAPFFASNTTLVAYFFGKELWDTGAGLVAAVLIAICPGYISRSVAGSYDNEAVAIFALLLTFYLFVKAVNTGSLAWALASAFGYFYMVSAWGGYVFIINLVPLYVLVLLITGRYSMRLYIAYNCMYILGMLLAMQIRFVGFQHVQSGEHMGAMGVFLLMQVFYFLDWVKYQLNDTKLFQTFLRITVTSAILVGGVAVGVGTASGYISPWTGRFYSLLDPTYAKDHIPIIASVSEHQPTAWSSFMFDYHILLFLFPAGLYFCFKRLTDATIFIVMYGLTSLYFAGVMVRLILVATPAVCLISAIAVSATIKNLTSLLRTKQKVSQTGSTKGAGSSKASSKVTLDQSQPFQKNGAIALLVGVFYLLSRYAIHCTWVTAEAYSSPSIVLAARGAHGNRIIFDDYREAYYWLRQNTATDAKIMSWWDYGYQITAMGNRTVIVDNNTWNNTHIATVGRAMSSYEDDAYDIMRSLDVNYVLVVFGGVTGYSSDDINKFLWMVRIGGGVFPVIKEPDYLVNGEFRVDKGASPKMLNCLMYKLCYYRFGELTTEYGKPPGYDRARGVEIGNKDIKLEHLEEAYTTSNWIVRIYRVKPPTNRL

Sequence caution

The sequence BX816490 differs from that shown. Reason: Frameshift

Features

Showing features for sequence conflict.

TypeIDPosition(s)Description
Sequence conflict595in Ref. 3; BX816490

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
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

Genome annotation databases

Similar Proteins

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