Short name=DDOST 48 kDa subunit
Short name=Oligosaccharyl transferase 48 kDa subunit
EC=2.4.99.18
Function
N結合型オリゴ糖鎖転移酵素複合体の基本的なサブユニットで、高マンノース型のオリゴ糖鎖を脂質結合型のオリゴ糖鎖ドナーからコンセンサスモチーフのアスパラギン残基側鎖に転移する反応を触媒する。
Essential subunit of the N-oligosaccharyl transferase (OST) complex which catalyzes the transfer of a high mannose oligosaccharide from a lipid-linked oligosaccharide donor to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains.
Catalytic activity
Dolichyl diphosphooligosaccharide + [protein]-L-asparagine = dolichyl diphosphate + a glycoprotein with the oligosaccharide chain attached by N-beta-D-glycosyl linkage to a protein L-asparagine.
Pathway
Protein modification; protein glycosylation.
Subunit structure
Component of the oligosaccharyltransferase (OST) complex. OST seems to exist in different forms which contain at least RPN1, RPN2, OST48, DAD1, OSTC, KRTCAP2 and either STT3A or STT3B. OST can form stable complexes with the Sec61 complex or with both the Sec61 and TRAP complexes even after release from the ribosome By similarity. Also identified as part of a complex which includes CANX, DERL1, DERL2, DDOST/OST48, RPN1, RPN2, SELK, VIMP, STT3A AND VCP. This contains known members of the OST complex and may be a form of this complex. Ref.9
Subcellular location
Endoplasmic reticulum membrane; Single-pass type I membrane protein.
Involvement in disease
Congenital disorder of glycosylation 1R (CDG1R) [MIM:614507]: A multisystem disorder caused by a defect in glycoprotein biosynthesis and characterized by under-glycosylated serum glycoproteins. Congenital disorders of glycosylation result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. The broad spectrum of features reflects the critical role of N-glycoproteins during embryonic development, differentiation, and maintenance of cell functions.
Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.10
Sequence similarities
Belongs to the DDOST 48 kDa subunit family.
