Enzymes
| UniProtKB help_outline | 1 proteins |
| Enzyme class help_outline |
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Reaction participants Show >> << Hide
- Name help_outline N-acetyl-α-D-galactosaminyl-(1→4)-N-acetyl-α-D-galactosaminyl-(1→3)-N,N'-diacetyl-α-D-bacillosaminyl-tri-trans,heptacis-undecaprenyl diphosphate Identifier CHEBI:68651 Charge -2 Formula C81H132N4O21P2 InChIKeyhelp_outline YKMPJLRXZZMPEK-PTNPFIJJSA-L SMILEShelp_outline C[C@H]1O[C@H](OP([O-])(=O)OP([O-])(=O)OC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(/C)CC\C=C(/C)CC\C=C(/C)CCC=C(C)C)[C@H](NC(C)=O)[C@@H](O[C@H]2O[C@H](CO)[C@H](O[C@H]3O[C@H](CO)[C@H](O)[C@H](O)[C@H]3NC(C)=O)[C@H](O)[C@H]2NC(C)=O)[C@@H]1NC(C)=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP-N-acetyl-α-D-galactosamine Identifier CHEBI:67138 Charge -2 Formula C17H25N3O17P2 InChIKeyhelp_outline LFTYTUAZOPRMMI-NESSUJCYSA-L SMILEShelp_outline CC(=O)N[C@@H]1[C@@H](O)[C@@H](O)[C@@H](CO)O[C@@H]1OP([O-])(=O)OP([O-])(=O)OC[C@H]1O[C@H]([C@H](O)[C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 42 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline [α-D-GalNAc-(1→4)]4-α-D-GalNAc-(1→3)-α-D-diNAcBac-tri-trans,hepta-cis-undecaprenyl diphosphate Identifier CHEBI:68653 Charge -2 Formula C105H171N7O36P2 InChIKeyhelp_outline YGYQMWIRLGPSQQ-MVDZMULYSA-L SMILEShelp_outline C[C@H]1O[C@H](OP([O-])(=O)OP([O-])(=O)OC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(\C)CC\C=C(/C)CC\C=C(/C)CC\C=C(/C)CCC=C(C)C)[C@H](NC(C)=O)[C@@H](O[C@H]2O[C@H](CO)[C@H](O[C@H]3O[C@H](CO)[C@H](O[C@H]4O[C@H](CO)[C@H](O[C@H]5O[C@H](CO)[C@H](O[C@H]6O[C@H](CO)[C@H](O)[C@H](O)[C@H]6NC(C)=O)[C@H](O)[C@H]5NC(C)=O)[C@H](O)[C@H]4NC(C)=O)[C@H](O)[C@H]3NC(C)=O)[C@H](O)[C@H]2NC(C)=O)[C@@H]1NC(C)=O 2D coordinates Mol file for the small molecule Search links Involved in 2 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline UDP Identifier CHEBI:58223 Charge -3 Formula C9H11N2O12P2 InChIKeyhelp_outline XCCTYIAWTASOJW-XVFCMESISA-K SMILEShelp_outline O[C@@H]1[C@@H](COP([O-])(=O)OP([O-])([O-])=O)O[C@H]([C@@H]1O)n1ccc(=O)[nH]c1=O 2D coordinates Mol file for the small molecule Search links Involved in 577 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,521 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:34519 | RHEA:34520 | RHEA:34521 | RHEA:34522 | |
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| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
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Publications
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In vitro assembly of the undecaprenylpyrophosphate-linked heptasaccharide for prokaryotic N-linked glycosylation.
Glover K.J., Weerapana E., Imperiali B.
Campylobacter jejuni has a general N-linked glycosylation pathway (encoded by the pgl gene cluster), which culminates in the transfer of a heptasaccharide: GalNAc-alpha1,4-GalNAc-alpha1,4-(Glcbeta1,3)-GalNAc-alpha1,4-GalNAc-alpha1,4-GalNAc-alpha1,3-Bac [where Bac is bacillosamine (2,4-diacetamido- ... >> More
Campylobacter jejuni has a general N-linked glycosylation pathway (encoded by the pgl gene cluster), which culminates in the transfer of a heptasaccharide: GalNAc-alpha1,4-GalNAc-alpha1,4-(Glcbeta1,3)-GalNAc-alpha1,4-GalNAc-alpha1,4-GalNAc-alpha1,3-Bac [where Bac is bacillosamine (2,4-diacetamido-2,4,6-trideoxyglucose)] from a membrane-anchored undecaprenylpyrophosphate (Und-PP)-linked donor to the asparagine side chain of proteins at the Asn-X-Ser/Thr motif. Herein we report, the cloning, overexpression, and purification of four of the glycosyltransferases (PglA, PglH, PglI, and PglJ) responsible for the biosynthesis of the Und-PP-linked heptasaccharide. Starting with chemically synthesized Und-PP-linked Bac and various combinations of enzymes, we have deduced the precise functions of these glycosyltransferases. PglA and PglJ add the first two GalNAc residues on to the isoprenoid-linked Bac carrier, respectively. Elongation of the trisaccharide with PglH results in a hexasaccharide revealing the polymerase activity of PglH. The final branching glucose is then added by PglI, which prefers native lipids for optimal activity. The sequential activities of the glycosyl transferases in the pathway can be reconstituted in vitro. This pathway represents an ideal venue for investigating the integrated functions of a series of enzymatic processes that occur at a membrane interface. << Less
Proc. Natl. Acad. Sci. U.S.A. 102:14255-14259(2005) [PubMed] [EuropePMC]
This publication is cited by 3 other entries.
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Campylobacter jejuni PglH is a single active site processive polymerase that utilizes product inhibition to limit sequential glycosyl transfer reactions.
Troutman J.M., Imperiali B.
Asparagine-linked protein glycosylation is essential for the virulence of the human gut mucosal pathogen Campylobacter jejuni . The heptasaccharide that is transferred to proteins is biosynthesized via the glycosyltransferase-catalyzed addition of sugar units to an undecaprenyl diphosphate-linked ... >> More
Asparagine-linked protein glycosylation is essential for the virulence of the human gut mucosal pathogen Campylobacter jejuni . The heptasaccharide that is transferred to proteins is biosynthesized via the glycosyltransferase-catalyzed addition of sugar units to an undecaprenyl diphosphate-linked carrier. Genetic studies on the heptasaccharide assembly enzymes have shown that PglH, which transfers three terminal N-acetyl-galactosamine (GalNAc) residues to the carrier polyisoprene, is essential for chick colonization by C. jejuni . While it is now clear that PglH catalyzes multiple transfer reactions, the mechanism whereby the reactions cease after the addition of just three GalNAc residues has yet to be understood. To address this issue, a series of mechanistic biochemical studies was conducted with purified native PglH. This enzyme was found to follow a processive mechanism under initial rate conditions; however, product inhibition and product accumulation led to PglH release of intermediate products prior to complete conversion to the native ultimate product. Point mutations of an essential EX(7)E sequence motif were used to demonstrate that a single active site was responsible for all three transferase reactions, and a homology model with the mannosyltransferase PimA, from Mycobacteria smegmatis , establishes the requirement of the EX(7)E motif in catalysis. Finally, increased binding affinity with increasing glycan size is proposed to provide PglH with a counting mechanism that does not allow the transfer of more than three GalNAc residues. These results provide important mechanistic insights into the function of the glycosyl transfer polymerase that is related to the virulence of C. jejuni . << Less
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Genetic and molecular analyses reveal an evolutionary trajectory for glycan synthesis in a bacterial protein glycosylation system.
Borud B., Viburiene R., Hartley M.D., Paulsen B.S., Egge-Jacobsen W., Imperiali B., Koomey M.
Although protein glycosylation systems are becoming widely recognized in bacteria, little is known about the mechanisms and evolutionary forces shaping glycan composition. Species within the genus Neisseria display remarkable glycoform variability associated with their O-linked protein glycosylati ... >> More
Although protein glycosylation systems are becoming widely recognized in bacteria, little is known about the mechanisms and evolutionary forces shaping glycan composition. Species within the genus Neisseria display remarkable glycoform variability associated with their O-linked protein glycosylation (pgl) systems and provide a well developed model system to study these phenomena. By examining the potential influence of two ORFs linked to the core pgl gene locus, we discovered that one of these, previously designated as pglH, encodes a glucosyltransferase that generates unique disaccharide products by using polyprenyl diphosphate-linked monosaccharide substrates. By defining the function of PglH in the glycosylation pathway, we identified a metabolic conflict related to competition for a shared substrate between the opposing glycosyltransferases PglA and PglH. Accordingly, we propose that the presence of a stereotypic, conserved deletion mutation inactivating pglH in strains of Neisseria gonorrhoeae, Neisseria meningitidis, and related commensals, reflects a resolution of this conflict with the consequence of reduced glycan diversity. This model of genetic détente is supported by the characterization of pglH "missense" alleles encoding proteins devoid of activity or reduced in activity such that they cannot exert their effect in the presence of PglA. Thus, glucose-containing glycans appear to be a trait undergoing regression at the genus level. Together, these findings document a role for intrinsic genetic interactions in shaping glycan evolution in protein glycosylation systems. << Less
Proc Natl Acad Sci U S A 108:9643-9648(2011) [PubMed] [EuropePMC]