Information on EC 2.4.1.261 - dolichyl-P-Man:Man8GlcNAc2-PP-dolichol alpha-1,2-mannosyltransferase

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The enzyme appears in viruses and cellular organisms

EC NUMBER
COMMENTARY hide
2.4.1.261
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RECOMMENDED NAME
GeneOntology No.
dolichyl-P-Man:Man8GlcNAc2-PP-dolichol alpha-1,2-mannosyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
dolichyl beta-D-mannosyl phosphate + D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->6)]-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol = D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->6)]-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol + dolichyl phosphate
show the reaction diagram
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
protein N-glycosylation (eukaryotic, high mannose)
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dolichyl-diphosphooligosaccharide biosynthesis
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N-Glycan biosynthesis
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Various types of N-glycan biosynthesis
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Metabolic pathways
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SYSTEMATIC NAME
IUBMB Comments
dolichyl beta-D-mannosyl phosphate:D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->6)]-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol alpha-1,2-mannosy
The formation of N-glycosidic linkages of glycoproteins involves the ordered assembly of the common Glc3Man9GlcNAc2 core-oligosaccharide on the lipid carrier dolichyl diphosphate. Early mannosylation steps occur on the cytoplasmic side of the endoplasmic reticulum with GDP-Man as donor, the final reactions from Man5GlcNAc2-PP-Dol to Man9Glc-NAc2-PP-Dol on the lumenal side use dolichyl beta-D-mannosyl phosphate. ALG9 mannosyltransferase catalyses the addition of two different alpha-1,2-mannose residues: the addition of alpha-1,2-mannose to Man6GlcNAc2-PP-Dol (EC 2.4.1.259) and the addition of alpha-1,2-mannose to Man8GlcNAc2-PP-Dol (EC 2.4.1.261).
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
dolichyl beta-D-mannosyl phosphate + D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->6)]-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol
D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->6)]-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol + dolichyl phosphate
show the reaction diagram
NATURAL SUBSTRATES
NATURAL PRODUCTS
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
REVERSIBILITY
r=reversible
ir=irreversible
?=not specified
dolichyl beta-D-mannosyl phosphate + D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->6)]-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol
D-Man-alpha-(1->2)-D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->3)-[D-Man-alpha-(1->2)-D-Man-alpha-(1->6)]-D-Man-alpha-(1->6)]-D-Man-beta-(1->4)-D-GlcNAc-beta-(1->4)-D-GlcNAc-diphosphodolichol + dolichyl phosphate
show the reaction diagram
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
LOCALIZATION
ORGANISM
UNIPROT
COMMENTARY hide
GeneOntology No.
LITERATURE
SOURCE
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lumen-oriented glycosyltransferase
Manually annotated by BRENDA team
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
cloning of human ALG9 (Y286C) cDNA into a yeast expression vector
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ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
R100W
residue R100 is located near the end of the largest luminal loop between the first two predicted transmembrane segments and is absolutely conserved in all known ALG9 enzymes. Mutation suppresses a dwarf mutant, bri1-9, the phenotypes of which are caused by endoplasmic reticulum retention and endoplasmic reticulum-associated degradation of a brassinosteroid receptor, BRASSINOSTEROID-INSENSITIVE 1, BR1. The mutation prevents the Glc3Man9GlcNAc2 assembly and inhibits the endoplasmic reticulum-associated degradation of bri1-9. Overexpression of EBS4 in the R100W bri1-9 mutant, which encodes the Arabidopsis ortholog of the yeast ALG12 catalyzing the ER luminal alpha1,6 Man addition, adds an alpha1,6 Man to the truncated N-glycan precursor accumulated in R100W bri1-9, promotes the bri1-9 endoplasmic reticulum-associated degradation, and neutralizes the R100W suppressor phenotype
E523K
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the ALG9 defect defines a form of congenital disorders of glycosylation named CDG-IL. The patient with this ALG9 defect, who presents with developmental delay, hypotonia, seizures, and hepatomegaly
Y286C
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patient, who is homozygous for the ALG9 mutation p.Y286C, deleterious effect Y286C on the ALG9 function. Compared the complementation efficiency of the wild-type and mutant ALG9 cDNA in yeast cells deficient for alg9. In an assay, the growth efficiency of the transformed yeast double mutant alg9 wbp1-2 is tested. Deficiency in lipid-linked oligosaccharide biosynthesis (alg9) in combination with reduced oligosaccharyltransferase activity (wbp1-2) results in a temperature-sensitive phenotype at 30°C. At this restrictive temperature, both the normal and mutant ALG9 cDNAs are able to restore growth. The HsALG9 transformants perform similar to the yeast alg9. The complementation with the mutant construct (HsALG9 (Y286C)) is less efficient, resulting is a reduced growth restoration. This difference becomes more prominent when the transformants are grown at 32°C. The hypoglycosylation of the alg9 yeast strain is reflected in the presence of CPY glycoforms lacking one or two N-linked oligosacharides. The human ALG9 cDNA complements the yeast mutation partially, as shown by the improved glycosylation of CPY. The complementation efficiency of the HsALG9 (Y286C) is less efficient and almost comparable to the empty vector
APPLICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
medicine
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homozygous splice variant NM_024740.2: c.1173+2T4A in the ALG9 gene causes rare lethal autosomal recessive Gillessen-Kaesbach-Nishimura skeletal dysplasia. Skipping of exon 10 leads to shorter RNA and results in an increase in monoglycosylated transferrin