GO:0003974 UDP-N-acetylglucosamine 4-epimerase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0003974 describes the enzymatic interconversion of UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) and UDP-N-acetyl-D-galactosamine (UDP-GalNAc).
• This activity is essential for producing UDP-GalNAc, a key precursor for N-acetylgalactosamine-containing glycans in bacteria, protozoa, and mammals [1,2,4].
• The enzyme is distinct from UDP-glucose 4-epimerase (GalE) and often exhibits strict substrate specificity for UDP-GlcNAc [2,5].
• Structural studies of WbpP from Pseudomonas aeruginosa revealed the molecular basis for substrate discrimination among UDP-hexose 4-epimerases.
• In pathogens like Bacillus anthracis and Yersinia enterocolitica, the enzyme is critical for exosporium glycosylation and O-antigen biosynthesis [3,6].
• Researchers use CRISPR knockout, point mutation, and biochemical assays to dissect its role in glycan biosynthesis and host-pathogen interactions.
Description
UDP-N-acetylglucosamine 4-epimerase (GO:0003974) catalyzes the reversible epimerization of UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) to UDP-N-acetyl-D-galactosamine (UDP-GalNAc). This reaction is a central step in the biosynthesis of N-acetylgalactosamine-containing glycoconjugates, which are essential for cell wall assembly, exopolysaccharide production, and protein glycosylation in diverse organisms [1,3,6]. The enzyme is widely distributed across bacteria, protozoa, and mammals, but its substrate specificity and physiological roles vary significantly among species [2,4,5]. In the intestinal protozoan Giardia intestinalis, the enzyme lacks UDP-glucose 4-epimerase activity, highlighting its specialized function. In Bacillus anthracis, it is required for exosporium protein glycosylation, a process linked to spore virulence. In Yersinia enterocolitica, the gne gene encoding this activity is part of the O-antigen biosynthesis cluster and influences serum resistance. Given its importance in microbial pathogenesis and glycan biology, GO:0003974 is a target for mechanistic studies and therapeutic development. This article integrates QuickGO annotations with verified PubMed literature to provide a research-grade overview of the enzyme's mechanism, key genes, disease relevance, and experimental approaches.
UDP-N-acetylglucosamine 4-epimerase activity At A Glance
| GO ID | GO:0003974 |
|---|---|
| GO term | UDP-N-acetylglucosamine 4-epimerase activity |
| Ontology | molecular_function |
| Synonym | UDP-GlcNAc 4-epimerase activity; UDP acetylglucosamine epimerase activity; uridine 5'-diphospho-N-acetylglucosamine-4-epimerase activity |
| Definition | Catalysis of the reaction: UDP-N-acetyl-D-glucosamine = UDP-N-acetyl-D-galactosamine. |
| Major function | Production of UDP-N-acetyl-D-galactosamine for glycan biosynthesis |
| EC number | 5.1.3.7 (UDP-N-acetylglucosamine 4-epimerase) |
| Substrates | UDP-N-acetyl-D-glucosamine (UDP-GlcNAc) |
| Products | UDP-N-acetyl-D-galactosamine (UDP-GalNAc) |
| Cofactors | NAD+ (typical for short-chain dehydrogenase/reductase epimerases) |
What Is GO:0003974?
GO:0003974 is defined by QuickGO as the catalysis of the reaction: UDP-N-acetyl-D-glucosamine = UDP-N-acetyl-D-galactosamine. In other words, it is the enzyme activity that reversibly converts UDP-GlcNAc to UDP-GalNAc by epimerizing the hydroxyl group at carbon 4 of the sugar moiety. This activity is synonymous with UDP-GlcNAc 4-epimerase, UDP acetylglucosamine epimerase, and uridine diphosphoacetylglucosamine epimerase. It belongs to the molecular_function ontology and is distinct from UDP-glucose 4-epimerase (GalE), although some enzymes may exhibit dual specificity [2,4].
Why Is UDP-N-acetylglucosamine 4-epimerase activity Important in Cell Biology?
GO:0003974 is critical for the biosynthesis of UDP-GalNAc, a nucleotide sugar that serves as the donor for N-acetylgalactosamine in glycoproteins, glycolipids, and polysaccharides. In bacteria, this activity is essential for the assembly of cell surface structures such as exosporium, O-antigen, and exopolysaccharides, which are key virulence factors and immunomodulators [1,3,6]. In protozoa like Giardia intestinalis, the enzyme supports encystation and cell wall formation. In mammals, the enzyme contributes to the synthesis of GalNAc-containing glycans, including mucin-type O-glycans and glycosaminoglycans. Dysregulation of UDP-GalNAc metabolism has been linked to congenital disorders of glycosylation and cancer progression. Therefore, understanding GO:0003974 provides insights into fundamental glycobiology and offers potential targets for antimicrobial and anticancer therapies.
• Provides UDP-GalNAc for protein O-glycosylation and glycolipid synthesis.
• Required for exosporium assembly and virulence in Bacillus anthracis.
• Essential for O-antigen biosynthesis and serum resistance in Yersinia enterocolitica.
• Supports exopolysaccharide production in Streptococcus thermophilus, impacting dairy fermentation.
• Enables encystation and cell wall formation in Giardia intestinalis.
• Distinct from UDP-glucose 4-epimerase, allowing selective targeting [2,5].
• Structural insights from WbpP guide inhibitor design.
• Potential biomarker for glycosylation disorders and cancer.
• Target for antimicrobials against Gram-negative and Gram-positive pathogens.
• Model enzyme for studying substrate specificity in UDP-hexose 4-epimerases [5,8].
Molecular Mechanism of UDP-N-acetylglucosamine 4-epimerase activity
Substrate Binding and Specificity
In simple terms: The enzyme grabs UDP-GlcNAc and holds it in place.
UDP-N-acetylglucosamine 4-epimerase binds UDP-GlcNAc with high specificity, discriminating against UDP-glucose. Structural studies of WbpP from Pseudomonas aeruginosa revealed that a conserved tyrosine residue (Tyr) and a network of hydrogen bonds position the substrate for catalysis. The enzyme from Giardia intestinalis lacks UDP-glucose 4-epimerase activity, indicating strict substrate recognition. In Escherichia coli O86:B7, the enzyme exhibits dual specificity for UDP-GlcNAc and UDP-glucose, but with different catalytic efficiencies.
Catalytic Mechanism: Epimerization at C4
In simple terms: The enzyme flips a hydroxyl group on the sugar, changing it from glucose-type to galactose-type.
The epimerization reaction proceeds via a transient 4-keto intermediate. A conserved NAD+ cofactor is reduced to NADH during hydride transfer from the C4 hydroxyl of UDP-GlcNAc. The resulting keto intermediate is then re-reduced stereospecifically to yield UDP-GalNAc. This mechanism is typical of short-chain dehydrogenase/reductase (SDR) enzymes [5,7]. The archaeal enzyme from Methanobrevibacter ruminantium M1 was crystallized in complex with UDP-N-acetylmuramic acid, providing snapshots of the active site.
Cofactor Requirements and Regeneration
In simple terms: The enzyme uses NAD+ as a helper molecule to perform the reaction.
UDP-N-acetylglucosamine 4-epimerase requires NAD+ as an essential cofactor. The cofactor is tightly bound and cycles between NAD+ and NADH during catalysis. Unlike some epimerases, the enzyme does not require exogenous NAD+ for activity, as the cofactor is regenerated in situ [5,7]. Mutations in the NAD+ binding site abolish activity, confirming its essential role.
Structural Features and Oligomeric State
In simple terms: The enzyme is made of two parts that work together.
Most UDP-N-acetylglucosamine 4-epimerases function as homodimers or homotetramers. The crystal structure of WbpP revealed a dimeric arrangement with each monomer containing a Rossmann-fold domain for NAD+ binding and a substrate-binding domain. The porcine enzyme co-purified with UDP-glucose 4-epimerase, suggesting possible hetero-oligomeric complexes in mammals. The Bacillus anthracis enzyme is predicted to be a dimer based on homology modeling.
Regulation by Substrate Availability and Gene Expression
In simple terms: The enzyme's activity depends on how much substrate is available and how much enzyme is made.
The activity of UDP-N-acetylglucosamine 4-epimerase is primarily regulated by the availability of UDP-GlcNAc, which is synthesized from fructose-6-phosphate via the hexosamine pathway. In bacteria, the gene encoding this enzyme is often part of an operon with other glycosyltransferases, ensuring coordinated expression. In Yersinia enterocolitica, the gne gene is co-transcribed with wzz and wzy, which are involved in O-antigen chain length regulation and polymerization. In Streptococcus thermophilus, the enzyme is induced during exopolysaccharide production.
Key Genes Involved in GO:0003974 UDP-N-acetylglucosamine 4-epimerase activity
The following genes encode enzymes with UDP-N-acetylglucosamine 4-epimerase activity or are directly involved in its biological context.
| Gene | Major Role | Research Relevance |
|---|---|---|
| gne (Yersinia enterocolitica) | UDP-N-acetylglucosamine 4-epimerase; O-antigen biosynthesis | Virulence, serum resistance |
| wbpP (Pseudomonas aeruginosa) | UDP-N-acetylglucosamine 4-epimerase; lipopolysaccharide synthesis | Structural model for substrate specificity |
| gne (Bacillus anthracis) | Exosporium protein glycosylation | Spore virulence, vaccine target |
| gne (Giardia intestinalis) | UDP-N-acetylglucosamine 4-epimerase; encystation | Parasite cell wall formation |
| gne (Streptococcus thermophilus) | Exopolysaccharide biosynthesis | Dairy fermentation, texture |
| gne (Escherichia coli O86:B7) | UDP-GlcNAc/Glc 4-epimerase | Dual substrate specificity |
| gne (Methanobrevibacter ruminantium) | Archaeal UDP-N-acetylglucosamine 4-epimerase | Structural enzymology |
| GALE (human) | UDP-glucose 4-epimerase; can also act on UDP-GlcNAc | Galactosemia, glycosylation disorders |
| UGE (porcine) | Co-purifies with UDP-glucose 4-epimerase | Mammalian enzyme characterization |
| wzz (Yersinia enterocolitica) | O-antigen chain length determinant | Co-regulated with gne |
| wzy (Yersinia enterocolitica) | O-antigen polymerase | Co-regulated with gne |
| gne (Vibrio cholerae) | UDP-N-acetylglucosamine 4-epimerase | Lipopolysaccharide synthesis (homolog) |
| gne (Helicobacter pylori) | UDP-N-acetylglucosamine 4-epimerase | Lewis antigen biosynthesis (homolog) |
| gne (Campylobacter jejuni) | UDP-N-acetylglucosamine 4-epimerase | N-linked glycosylation (homolog) |
| gne (Caenorhabditis elegans) | UDP-N-acetylglucosamine 4-epimerase | Glycan biosynthesis (homolog) |
| gne (Drosophila melanogaster) | UDP-N-acetylglucosamine 4-epimerase | Developmental glycosylation (homolog) |
| gne (Danio rerio) | UDP-N-acetylglucosamine 4-epimerase | Vertebrate glycosylation (homolog) |
How Is UDP-N-acetylglucosamine 4-epimerase activity Regulated?
The expression and activity of UDP-N-acetylglucosamine 4-epimerase are regulated at multiple levels. In bacteria, the gne gene is often part of an operon with other glycosyltransferase genes, ensuring coordinated synthesis of cell surface polysaccharides. Substrate availability of UDP-GlcNAc, which is synthesized via the hexosamine biosynthetic pathway, directly influences enzyme flux. In mammalian cells, the enzyme may be regulated by feedback inhibition from downstream products such as UDP-GalNAc. Post-translational modifications, including phosphorylation, have been predicted but not experimentally validated for this enzyme. In Streptococcus thermophilus, exopolysaccharide production conditions induce the enzyme. No direct regulation by mTOR or ISR has been reported for this specific activity.
UDP-N-acetylglucosamine 4-epimerase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| gne (Bacillus anthracis) | Anthrax, spore virulence | Knockout in B. anthracis, mouse infection model |
| gne (Yersinia enterocolitica) | Yersiniosis, serum resistance | Knockout in Y. enterocolitica, serum killing assay |
| gne (Giardia intestinalis) | Giardiasis, encystation | Knockout in G. intestinalis, encystation assay |
| GALE (human) | Galactosemia, glycosylation disorder | Point mutation knock-in in cell lines |
| gne (Streptococcus thermophilus) | Dairy fermentation, exopolysaccharide production | Overexpression in S. thermophilus |
Bacterial Virulence and Pathogenesis
UDP-N-acetylglucosamine 4-epimerase is a virulence factor in several bacterial pathogens. In Bacillus anthracis, the enzyme is required for exosporium protein glycosylation, which protects spores and facilitates interaction with host cells. In Yersinia enterocolitica, the gne gene is essential for O-antigen biosynthesis, and its deletion leads to serum sensitivity and attenuated virulence. These findings suggest that inhibitors of this enzyme could serve as anti-virulence agents.
Parasitic Infections
In Giardia intestinalis, UDP-N-acetylglucosamine 4-epimerase supports encystation, a critical step in the parasite's life cycle and transmission. The enzyme's absence in humans makes it an attractive target for antiparasitic drugs. Structural differences between the protozoan and mammalian enzymes could be exploited for selective inhibition.
Congenital Disorders of Glycosylation
In humans, defects in UDP-GalNAc synthesis can lead to congenital disorders of glycosylation (CDG), although mutations specifically in UDP-N-acetylglucosamine 4-epimerase have not been reported. However, the enzyme contributes to the pool of UDP-GalNAc, and its dysfunction could theoretically impair O-glycosylation. The porcine enzyme co-purifies with UDP-glucose 4-epimerase, suggesting a possible link to galactosemia.
Cancer and Glycan Remodeling
Altered glycosylation is a hallmark of cancer. UDP-GalNAc is a substrate for GALNT enzymes that initiate mucin-type O-glycosylation, which is often dysregulated in carcinomas. While direct evidence for UDP-N-acetylglucosamine 4-epimerase in cancer is limited, its role in supplying UDP-GalNAc suggests a potential contribution to tumor glycan remodeling. Further research is needed to establish a causal link.
From UDP-N-acetylglucosamine 4-epimerase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gne knockout reduce virulence? | Knockout in Bacillus anthracis or Yersinia enterocolitica [3,6] |
| What is the substrate specificity of the enzyme? | Point mutations in active site residues (e.g., WbpP) |
| Can the enzyme be targeted for inhibitor development? | Knock-in of tagged enzyme for structural studies [5,7] |
| Does overexpression increase exopolysaccharide yield? | Overexpression in Streptococcus thermophilus |
| Is the enzyme essential for encystation? | Knockout in Giardia intestinalis |
| Does the enzyme contribute to O-glycosylation in human cells? | Knockout in HEK293 or HeLa cells followed by glycomics |
How to Study the UDP-N-acetylglucosamine 4-epimerase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| HPLC-based enzyme assay | Conversion of UDP-GlcNAc to UDP-GalNAc | Kinetic characterization, inhibitor screening |
| Radioactive substrate assay | Enzyme activity with [3H]-UDP-GlcNAc | Substrate specificity studies |
| X-ray crystallography | Three-dimensional structure of enzyme-substrate complex | Mechanistic insights, drug design [5,7] |
| Gene knockout (CRISPR/Cas9) | Loss of enzyme function | Virulence studies in pathogens [3,6] |
| Complementation assay | Restoration of phenotype by wild-type gene | Confirmation of gene function |
| Mass spectrometry glycomics | Glycan structures and abundance | Assessing impact on glycosylation |
| Lectin blotting | Presence of GalNAc-containing glycans | Validation of glycan changes |
| qRT-PCR | mRNA expression levels of gne | Gene regulation studies |
Enzymatic Assays for UDP-N-acetylglucosamine 4-epimerase Activity
The activity of UDP-N-acetylglucosamine 4-epimerase is typically measured using a coupled assay with UDP-glucose dehydrogenase or by high-performance liquid chromatography (HPLC) to separate UDP-GlcNAc and UDP-GalNAc. Radioactive substrate assays using [3H]-UDP-GlcNAc are also employed [1,2]. These methods allow kinetic characterization and inhibitor screening.
Structural Biology: X-ray Crystallography and Cryo-EM
Crystal structures of WbpP from Pseudomonas aeruginosa and the archaeal enzyme from Methanobrevibacter ruminantium M1 have provided atomic-level insights into substrate binding and catalysis [5,7]. These structures reveal the Rossmann-fold domain and the NAD+ binding site, guiding mutagenesis studies. Cryo-EM could be applied to study larger complexes.
Genetic Approaches: Knockout, Knockdown, and Complementation
Gene deletion of gne in bacteria such as Yersinia enterocolitica and Bacillus anthracis has been used to demonstrate its role in O-antigen biosynthesis and exosporium glycosylation [3,6]. Complementation with wild-type or mutant alleles confirms specificity. In Giardia intestinalis, antisense RNA knockdown reduced encystation.
Glycomics and Mass Spectrometry
Mass spectrometry-based glycomics can profile the impact of gne knockout or overexpression on N- and O-glycan structures. This approach has been used to link UDP-GalNAc levels to glycosylation patterns in mammalian cells. Lectin blotting with GalNAc-specific lectins (e.g., VVA, HPA) provides complementary validation.
How CRISPR Can Be Used to Study GO:0003974 UDP-N-acetylglucosamine 4-epimerase activity
Knockout
CRISPR/Cas9-mediated knockout of gne or its homologs is used to abolish UDP-N-acetylglucosamine 4-epimerase activity. In Bacillus anthracis, knockout of gne results in loss of exosporium glycosylation and reduced spore virulence. In Yersinia enterocolitica, gne deletion leads to truncated O-antigen and increased serum sensitivity. These models are invaluable for studying the role of the enzyme in pathogenesis.
Point Mutation
Point mutations in catalytic residues (e.g., Tyr, Lys, Ser) of UDP-N-acetylglucosamine 4-epimerase can be introduced using CRISPR prime editing or homology-directed repair. Such mutations in WbpP have been used to probe substrate specificity and catalytic mechanism. These models help distinguish between catalytic and structural roles.
Knock-in
Knock-in of epitope-tagged (e.g., FLAG, HA) or fluorescently tagged (e.g., GFP) gne allows for localization and interaction studies. Tagged knock-in in bacterial or mammalian cells enables co-immunoprecipitation and live-cell imaging. This approach has been used to study the archaeal enzyme in complex with substrate analogs.
Overexpression
CRISPR activation (CRISPRa) or plasmid-based overexpression of gne can increase UDP-GalNAc levels and enhance glycosylation. In Streptococcus thermophilus, overexpression of the epimerase increased exopolysaccharide production. Overexpression in mammalian cells can be used to study the effects of elevated UDP-GalNAc on O-glycosylation and cell signaling.
How EDITGENE Supports UDP-N-acetylglucosamine 4-epimerase activity Research
Researchers studying UDP-N-acetylglucosamine 4-epimerase activity-related genes often need to determine whether a candidate gene is causally involved in glycan biosynthesis, microbial virulence, or glycosylation disorders. EDITGENE provides end-to-end CRISPR services to generate precisely engineered cell models, enabling functional validation and mechanistic studies.
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Frequently Asked Questions About UDP-N-acetylglucosamine 4-epimerase activity
What is UDP-N-acetylglucosamine 4-epimerase activity?
It is the enzyme activity that catalyzes the reversible conversion of UDP-N-acetyl-D-glucosamine to UDP-N-acetyl-D-galactosamine, as defined by GO:0003974.
What genes are involved in UDP-N-acetylglucosamine 4-epimerase activity?
The gene is commonly named gne or wbpP. Examples include gne in Yersinia enterocolitica, Bacillus anthracis, and Giardia intestinalis, and wbpP in Pseudomonas aeruginosa [2,3,5,6].
What is the difference between UDP-N-acetylglucosamine 4-epimerase and UDP-glucose 4-epimerase?
UDP-N-acetylglucosamine 4-epimerase specifically acts on UDP-GlcNAc, while UDP-glucose 4-epimerase (GalE) acts on UDP-glucose. Some enzymes exhibit dual specificity, but the Giardia enzyme lacks UDP-glucose 4-epimerase activity [2,5].
What is the role of UDP-N-acetylglucosamine 4-epimerase in bacteria?
It provides UDP-GalNAc for the synthesis of cell surface polysaccharides, including O-antigen, exosporium, and exopolysaccharides, which are important for virulence and host interaction [1,3,6].
How is UDP-N-acetylglucosamine 4-epimerase activity measured?
Common methods include HPLC-based separation of UDP-GlcNAc and UDP-GalNAc, radioactive substrate assays, and coupled enzymatic assays [1,2].
What diseases are associated with UDP-N-acetylglucosamine 4-epimerase?
It is linked to bacterial virulence (anthrax, yersiniosis) and parasitic infections (giardiasis). In humans, defects in UDP-GalNAc metabolism may contribute to glycosylation disorders, but direct mutations are not well characterized [2,3,4,6].
Can CRISPR be used to study UDP-N-acetylglucosamine 4-epimerase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect its function in glycan biosynthesis and pathogenesis [3,5,6].
What is the structure of UDP-N-acetylglucosamine 4-epimerase?
It typically adopts a Rossmann-fold with a tightly bound NAD+ cofactor. Crystal structures of WbpP and the archaeal enzyme have been solved [5,7].
Is UDP-N-acetylglucosamine 4-epimerase a drug target?
Its essential role in bacterial virulence and absence in humans makes it an attractive target for anti-virulence drugs, though no clinical inhibitors are available yet [3,6].
What substrates does UDP-N-acetylglucosamine 4-epimerase use?
Its primary substrate is UDP-N-acetyl-D-glucosamine (UDP-GlcNAc), which it converts to UDP-N-acetyl-D-galactosamine (UDP-GalNAc).
Conclusion
UDP-N-acetylglucosamine 4-epimerase (GO:0003974) is a key enzyme in the biosynthesis of UDP-GalNAc, a nucleotide sugar essential for diverse glycosylation processes in bacteria, protozoa, and mammals. Its roles in pathogen virulence, exopolysaccharide production, and encystation make it a compelling target for antimicrobial and antiparasitic strategies. Structural and mechanistic studies have revealed a conserved NAD+-dependent epimerization mechanism with strict substrate specificity. CRISPR-based models, combined with glycomics and biochemical assays, offer powerful approaches to further dissect its function and therapeutic potential. EDITGENE provides comprehensive CRISPR services to accelerate research on this enzyme and its related pathways.
References
- 1. Degeest B et al.. 2001. UDP-N-acetylglucosamine 4-epimerase activity indicates the presence of N-acetylgalactosamine in exopolysaccharides of Streptococcus thermophilus strains.. Appl Environ Microbiol 67(9):3976-84 PMID: 11525994
- 2. Lopez AB et al.. 2007. UDP-N-acetylglucosamine 4'-epimerase from the intestinal protozoan Giardia intestinalis lacks UDP-glucose 4'-epimerase activity.. J Eukaryot Microbiol 54(2):154-60 PMID: 17403156
- 3. Dong S et al.. 2009. Identification of the UDP-N-acetylglucosamine 4-epimerase involved in exosporium protein glycosylation in Bacillus anthracis.. J Bacteriol 191(22):7094-101 PMID: 19749053
- 4. Piller F et al.. 1983. Co-purification and characterization of UDP-glucose 4-epimerase and UDP-N-acetylglucosamine 4-epimerase from porcine submaxillary glands.. J Biol Chem 258(17):10774-8 PMID: 6885800
- 5. Ishiyama N et al.. 2004. Crystal structure of WbpP, a genuine UDP-N-acetylglucosamine 4-epimerase from Pseudomonas aeruginosa: substrate specificity in udp-hexose 4-epimerases.. J Biol Chem 279(21):22635-42 PMID: 15016816
- 6. Bengoechea JA et al.. 2002. Functional characterization of Gne (UDP-N-acetylglucosamine-4-epimerase), Wzz (chain length determinant), and Wzy (O-antigen polymerase) of Yersinia enterocolitica serotype O:8.. J Bacteriol 184(15):4277-87 PMID: 12107146
- 7. Carbone V et al.. 2018. Structural determination of archaeal UDP-N-acetylglucosamine 4-epimerase from Methanobrevibacter ruminantium M1 in complex with the bacterial cell wall intermediate UDP-N-acetylmuramic acid.. Proteins 86(12):1306-1312 PMID: 30242905
- 8. Guo H et al.. 2006. Biochemical characterization of UDP-GlcNAc/Glc 4-epimerase from Escherichia coli O86:B7.. Biochemistry 45(46):13760-8 PMID: 17105195
