InterPro: IPR007676 Ribophorin I

Ribophorin I is an essential subunit of oligosaccharyltransferase (OST), which is also known as dolichyl-diphosphooligosaccharide--protein glycosyltransferase, (EC:2.4.1.119). OST catalyses the transfer of an oligosaccharide from dolichol pyrophosphate to selected asparagine residues of nascent polypeptides as they are translocated into the lumen of the rough endoplasmic reticulum. Ribophorin I and OST48 are thought to be responsible for OST catalytic activity [1]. Both yeast and mammalian proteins are glycosylated but the sites are not conserved. Glycosylation may contribute towards general solubility but is unlikely to be involved in a specific biochemical function [2]. Most family members are predicted to have a transmembrane helix at the C terminus of this region.