Information on EC 2.4.1.186 - glycogenin glucosyltransferase and Organism(s) Homo sapiens and UniProt Accession P46976

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UNIPROT: P46976
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The expected taxonomic range for this enzyme is: Eukaryota, Bacteria


The taxonomic range for the selected organisms is: Homo sapiens

EC NUMBER
COMMENTARY hide
2.4.1.186
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RECOMMENDED NAME
GeneOntology No.
glycogenin glucosyltransferase
REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
UDP-alpha-D-glucose + glycogenin = UDP + alpha-D-glucosylglycogenin
show the reaction diagram
conformational plasticity of glycogenin and coexistence of two modes of glucosylation as integral to its catalytic mechanism, possible SNi-like mechanism for glucosyl-transfer, overview
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REACTION TYPE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
hexosyl group transfer
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-
-
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
glycogen biosynthesis II (from UDP-D-Glucose)
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glycogen biosynthesis
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SYSTEMATIC NAME
IUBMB Comments
UDP-alpha-D-glucose:glycogenin alpha-D-glucosyltransferase
The first reaction of this enzyme is to catalyse its own glucosylation, normally at Tyr-194 of the protein if this group is free. When Tyr-194 is replaced by Thr or Phe, the enzyme's Mn2+-dependent self-glucosylation activity is lost but its intermolecular transglucosylation ability remains [7]. It continues to glucosylate an existing glucosyl group until a length of about 5--13 residues has been formed. Further lengthening of the glycogen chain is then carried out by EC 2.4.1.11, glycogen (starch) synthase. The enzyme is not highly specific for the donor, using UDP-xylose in addition to UDP-glucose (although not glucosylating or xylosylating a xylosyl group so added). It can also use CDP-glucose and TDP-glucose, but not ADP-glucose or GDP-glucose. Similarly it is not highly specific for the acceptor, using water (i.e. hydrolysing UDP-glucose) among others. Various forms of the enzyme exist, and different forms predominate in different organs. Thus primate liver contains glycogenin-2, of molecular mass 66 kDa, whereas the more widespread form is glycogenin-1, with a molecular mass of 38 kDa.
CAS REGISTRY NUMBER
COMMENTARY hide
117590-73-5
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ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
malfunction
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the Thr83Met mutation, which causes glycogen storage disease XV, is conformationally locked in the ground state and catalytically inactive
physiological function
malfunction
physiological function
additional information
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
UDP-alpha-D-glucose + glycogenin
UDP + alpha-D-glucosylglycogenin
show the reaction diagram
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autoglucosylation by glycogenin-1
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-
?
UDP-alpha-D-glucose + glycogenin-1
UDP + alpha-D-glucosylglycogenin-1
show the reaction diagram
UDP-glucose + glycogenin
UDP + glucosylated glycogenin
show the reaction diagram
essential for the formation of glycogen granules, binds a chain of 5-13 glucose molecules at a specific tyrosine residue (Y194) by autoglycosylation
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-
?
UDP-alpha-D-glucose + glycogenin
UDP + alpha-D-glucosylglycogenin
show the reaction diagram
-
autoglucosylation by glycogenin-1
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-
?
UDP-alpha-D-glucose + glycogenin-2
UDP + alpha-D-glucosylglycogenin-2
show the reaction diagram
self-glucosylation of the glycosyltransferase glycogenin-2
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-
?
UDP-glucose + glycogenin
UDP + glucosylated glycogenin
show the reaction diagram
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-
-
-
?
UDP-glucose + glycogenin
UDP + glucosylglycogenin
show the reaction diagram
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increases in glycogenin and glycogenin mRNA accompany glycogen resynthesis in human skeletal muscle. Glycogenin is a self-glycosylating protein primer that initiates glycogen granule formation
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?
additional information
?
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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
UDP-alpha-D-glucose + glycogenin
UDP + alpha-D-glucosylglycogenin
show the reaction diagram
-
autoglucosylation by glycogenin-1
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-
?
UDP-alpha-D-glucose + glycogenin-1
UDP + alpha-D-glucosylglycogenin-1
show the reaction diagram
O15488
self-glucosylation of the glycosyltransferase glycogenin-1
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-
?
UDP-glucose + glycogenin
UDP + glucosylated glycogenin
show the reaction diagram
P46976
essential for the formation of glycogen granules, binds a chain of 5-13 glucose molecules at a specific tyrosine residue (Y194) by autoglycosylation
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-
?
UDP-alpha-D-glucose + glycogenin
UDP + alpha-D-glucosylglycogenin
show the reaction diagram
-
autoglucosylation by glycogenin-1
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-
?
UDP-alpha-D-glucose + glycogenin-2
UDP + alpha-D-glucosylglycogenin-2
show the reaction diagram
O15488
self-glucosylation of the glycosyltransferase glycogenin-2
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-
?
UDP-glucose + glycogenin
UDP + glucosylated glycogenin
show the reaction diagram
-
-
-
-
?
UDP-glucose + glycogenin
UDP + glucosylglycogenin
show the reaction diagram
-
increases in glycogenin and glycogenin mRNA accompany glycogen resynthesis in human skeletal muscle. Glycogenin is a self-glycosylating protein primer that initiates glycogen granule formation
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-
?
METALS and IONS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
Mg2+
required
Mn2+
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required
pH OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
7.4
assay at
7.5
assay at
TEMPERATURE OPTIMUM
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE TISSUE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
SOURCE
from breast tissue
Manually annotated by BRENDA team
additional information
PDB
SCOP
CATH
UNIPROT
ORGANISM
Homo sapiens;
MOLECULAR WEIGHT
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
40000
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recombinant His-tagged unglucosylated glycogenin-1, gel filtration
41000
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recombinant His-tagged autoglucosylated glycogenin-1, gel filtration
SUBUNITS
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
additional information
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hGYG1 ccurs in two distinct states, the ground state and the active state, the two states are interchangeable during catalysis and involve conformational rearrangements in three regions that influence active site accessibility, overview
POSTTRANSLATIONAL MODIFICATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
glycoprotein
the degree of glycosylation of the enzyme is modest
glycoprotein
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
purified recombinant hGYG1 in complex with Mn2+ and UDP-alpha-glucose, 10 mg/ml hGYG1 with various ligands by sitting drop vapor diffusion at 20°C, X-ray diffraction structure determination and analysis at 2.6 A, molecular replacement
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Purification/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
recombinant GST-tagged glycogen synthase in complex with glycogenin-1 from Sf9 insect cells by glutathione affinity chromatography and gel filtration
recombinant His-tagged wild-type and mutant enzymes from Escherichia coli strain BL21(DE3) by nickel affinity chrmatography
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recombinant His6-tagged wild-type and mutant glycogenin-1 from HEK-293 cells by nickel affinity chromatography
recombinant His-tagged wild-type and mutant enzymes from cell-free expression by nickel affinity chromatography
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recombinant His6-tagged wild-type and mutant glycogenin-2 from HEK-293 cells by nickel affinity chromatography
Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
expression of His-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3)
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gene GYG1, recombinant expression of functional GST-tagged human muscle glycogen synthase in complex with human glycogenin-1 in Spodoptera frugiperda Sf9 cells using a bicistronic pFastBac™-Dual expression vector and baculovirus transfection
recombinant expression of His6-tagged wild-type and mutant enzymes glycogenin-1 in HEK-293 cells. Coexpression of wild-type glycogenin-2 together with different glycogenin-1 variants using a cell-free system, coexpression of functional glycogenin-1 and glycogenin-2 increases the glucosylation of glycogenin-2
cell-free expression of His-tagged wild-type and mutant enzymes
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expressed in C2C12 cells
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gene GYG2, genotyping
recombinant expression of His6-tagged wild-type and mutant glycogenin-2 in HEK-293 cells. Coexpression of wild-type glycogenin-2 together with different glycogenin-1 variants using a cell-free system, coexpression of functional glycogenin-1 and glycogenin-2 increases the glucosylation of glycogenin-2
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
T83A
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site-directed mutagenesis, the mutant shows no incorporation of glucose, no autoglycosylation
T83C
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site-directed mutagenesis, the mutant shows no incorporation of glucose, no autoglycosylation
T83F
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site-directed mutagenesis, the mutant shows no incorporation of glucose, no autoglycosylation
T83M
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naturally occuring mutation, glycogenin-1 with the Thr83Met substitution is unable to form the glucose-O-tyrosine linkage at tyrosine 195 unless co-expressed with the catalytically active Tyr195Phe glycogenin-1. The mutant shows no incorporation of glucose, no autoglycosylation
T83S
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site-directed mutagenesis, the mutant is catalytically active
T83V
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site-directed mutagenesis, the mutant shows no incorporation of glucose, no autoglycosylation
T83Y
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site-directed mutagenesis, the mutant shows no incorporation of glucose, no autoglycosylation
Y195F
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site-directed mutagenesis, glycogenin-1 with the Thr83Met substitution is unable to form the glucose-O-tyrosine linkage at tyrosine 195 unless co-expressed with the catalytically active Tyr195Phe glycogenin-1
additional information
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non-glucosylated glycogenin-1 constructs, with various amino acid substitutions in position 83 and 195, are expressed in a cell-free expression system and autoglucosylated in vitro