UDP-N-acetylglucosamine 2-epimerase [Cell wall/membrane/envelope biogenesis].

UDP-N-acetylglucosamine 2-epimerase. This cytosolic enzyme converts UDP-N-acetyl-D-glucosamine to UDP-N-acetyl-D-mannosamine. In E. coli, this is the first step in the pathway of enterobacterial common antigen biosynthesis.Members of this orthology group have many gene symbols, often reflecting the overall activity of the pathway and/or operon that includes it. Symbols include epsC (exopolysaccharide C) in Burkholderia solanacerum, cap8P (type 8 capsule P) in Staphylococcus aureus, and nfrC in an older designation based on the effects of deletion on phage N4 adsorption. Epimerase activity was also demonstrated in a bifunctional rat enzyme, for which the N-terminal domain appears to be orthologous. The set of proteins found above the suggested cutoff includes E. coli WecB in one of two deeply branched clusters and the rat UDP-N-acetylglucosamine 2-epimerase domain in the other. [Cell envelope, Biosynthesis and degradation of surface polysaccharides and lipopolysaccharides]

UDP-N-acetylglucosamine 2-epimerase and similar proteins. Bacterial members of the UDP-N-Acetylglucosamine (GlcNAc) 2-Epimerase family (EC 5.1.3.14) are known to catalyze the reversible interconversion of UDP-GlcNAc and UDP-N-acetylmannosamine (UDP-ManNAc). The enzyme serves to produce an activated form of ManNAc residues (UDP-ManNAc) for use in the biosynthesis of a variety of cell surface polysaccharides; The mammalian enzyme is bifunctional, catalyzing both the inversion of stereochemistry at C-2 and the hydrolysis of the UDP-sugar linkage to generate free ManNAc. It also catalyzes the phosphorylation of ManNAc to generate ManNAc 6-phosphate, a precursor to salic acids. In mammals, sialic acids are found at the termini of oligosaccharides in a large variety of cell surface glycoconjugates and are key mediators of cell-cell recognition events. Mutations in human members of this family have been associated with Sialuria, a rare disease caused by the disorders of sialic acid metabolism. This family belongs to the GT-B structural superfamily of glycoslytransferases, which have characteristic N- and C-terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility.

UDP-N-acetylglucosamine 2-epimerase. This family consists of UDP-N-acetylglucosamine 2-epimerases EC:5.1.3.14 this enzyme catalyzes the production of UDP-ManNAc from UDP-GlcNAc. Note that some of the enzymes is this family are bifunctional, in these instances Pfam matches only the N-terminal half of the protein suggesting that the additional C-terminal part (when compared to mono-functional members of this family) is responsible for the UPD-N-acetylmannosamine kinase activity of these enzymes. This hypothesis is further supported by the assumption that the C-terminal part of rat Gne is the kinase domain.

phosphatidyl-myo-inositol mannosyltransferase. This family is most closely related to the GT4 family of glycosyltransferases and named after PimA in Propionibacterium freudenreichii, which is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIM) which are early precursors in the biosynthesis of lipomannans (LM) and lipoarabinomannans (LAM), and catalyzes the addition of a mannosyl residue from GDP-D-mannose (GDP-Man) to the position 2 of the carrier lipid phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1). Glycosyltransferases catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The acceptor molecule can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. This group of glycosyltransferases is most closely related to the previously defined glycosyltransferase family 1 (GT1). The members of this family may transfer UDP, ADP, GDP, or CMP linked sugars. The diverse enzymatic activities among members of this family reflect a wide range of biological functions. The protein structure available for this family has the GTB topology, one of the two protein topologies observed for nucleotide-sugar-dependent glycosyltransferases. GTB proteins have distinct N- and C- terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility. The members of this family are found mainly in certain bacteria and archaea.

Crystalstructure of Bacillus subtilis UDP-GlcNAc 2-epimerase in complex with UDP-GlcNAc and UDP [Bacillus subtilis subsp. subtilis str. 168],4FKZ_B Crystal structure of Bacillus subtilis UDP-GlcNAc 2-epimerase in complex with UDP-GlcNAc and UDP [Bacillus subtilis subsp. subtilis str. 168]

Crystalstructure of UDP-N-acetylglucosamine 2-epimerase [Bacillus subtilis],1O6C_B Crystal structure of UDP-N-acetylglucosamine 2-epimerase [Bacillus subtilis]

AStructural Basis for the allosteric regulation of non-hydrolyzing UDP-GlcNAc 2-epimerases [Bacillus anthracis],3BEO_B A Structural Basis for the allosteric regulation of non-hydrolyzing UDP-GlcNAc 2-epimerases [Bacillus anthracis]

2.2Angstrom Resolution Crystal Structure of putative UDP-N-acetylglucosamine 2-epimerase from Listeria monocytogenes [Listeria monocytogenes EGD-e],3OT5_B 2.2 Angstrom Resolution Crystal Structure of putative UDP-N-acetylglucosamine 2-epimerase from Listeria monocytogenes [Listeria monocytogenes EGD-e],3OT5_C 2.2 Angstrom Resolution Crystal Structure of putative UDP-N-acetylglucosamine 2-epimerase from Listeria monocytogenes [Listeria monocytogenes EGD-e],3OT5_D 2.2 Angstrom Resolution Crystal Structure of putative UDP-N-acetylglucosamine 2-epimerase from Listeria monocytogenes [Listeria monocytogenes EGD-e]

S.aureus MnaA-UDP co-structure [Staphylococcus aureus],5ENZ_B S. aureus MnaA-UDP co-structure [Staphylococcus aureus]

Putative UDP-N-acetylglucosamine 2-epimerase OS=Clostridium acetobutylicum (strain ATCC 824 / DSM 792 / JCM 1419 / LMG 5710 / VKM B-1787) OX=272562 GN=CA_C2874 PE=3 SV=2

Putative UDP-N-acetylglucosamine 2-epimerase OS=Thermotoga maritima (strain ATCC 43589 / DSM 3109 / JCM 10099 / NBRC 100826 / MSB8) OX=243274 GN=TM_1034 PE=3 SV=1

UDP-N-acetylglucosamine 2-epimerase OS=Bacillus subtilis (strain 168) OX=224308 GN=mnaA PE=1 SV=1

Probable UDP-N-acetylglucosamine 2-epimerase OS=Ralstonia solanacearum OX=305 GN=epsC PE=3 SV=2

Probable UDP-N-acetylglucosamine 2-epimerase OS=Ralstonia solanacearum (strain GMI1000) OX=267608 GN=epsC PE=3 SV=1