Dolichyl-Diphosphooligosaccharide--Protein Glycosyltransferase Subunit 1 (OST1) Saccharomyces Cerevisiae Recombinant Protein

Function: Essential subunit of N-oligosaccharyl transferase enzyme which catalyzes the transfer of a high mannose oligosaccharide to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains. 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.

Catalytic activity: Dolichyl diphosphooligosaccharide + protein L-asparagine = dolichyl diphosphate + a glycoprotein with the oligosaccharide chain attached by N-glycosyl linkage to protein L-asparagine.

Pathway: Protein modification; protein glycosylation.

Subunit structure: Component of the oligosaccharyl transferase (OST) complex, which appears to exist in two assemblies comprising OST1, OST2, OST4, OST5, STT3, SWP1, WPB1, and either OST3 or OST6. OST1 and OST5 probably form a subcomplex. OST1 may interact directly with OST2 OST3, OST5, OST6, WBP1 AND SWP1. Interacts with SEC61, SBH1 and SSS1. Ref.5 Ref.6 Ref.12 Ref.13

Subcellular location: Endoplasmic reticulum membrane; Single-pass type I membrane protein.

Miscellaneous: Present with 11900 molecules/cell in log phase SD medium.

Sequence similarities: Belongs to the OST1 family.