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Escherichia coli K-12 substr. MG1655 Pathway: colanic acid building blocks biosynthesis
Traceable author statement to experimental support

Pathway diagram: colanic acid building blocks biosynthesis

If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.

Locations of Mapped Genes:

Schematic showing all replicons, marked with selected genes

Genetic Regulation Schematic

Genetic regulation schematic for colanic acid building blocks biosynthesis

Superclasses: BiosynthesisCarbohydrates Biosynthesis

Colanic acid, also known as the M antigen, is an extracellular polysaccharide found in Enterobacteriaceae. It is a polyanionic heteropolysaccharide containing a repeat unit with D-glucose, L-fucose, D-galactose, and D-glucuronate sugars that are nonstoichiometrically decorated with O-acetyl and pyruvate side chains [Grant69, Garegg71]. The sugars need to be activated in the form of nucleotide sugars ( UDP-α-D-glucose, GDP-β-L-fucose, UDP-α-D-galactose and UDP-α-D-glucuronate, respectively) prior to their assembly [Stevenson96, Stout96].

The colanic acid polysaccharide repeat is assembled on the membrane lipid all-trans-dodecaprenyl diphosphate by a series of glycosyl transferases on the cytoplasmic face of the inner membrane, after which the single repeat is flipped to the periplasmic side and polymerized by the Wzy-dependent pathway (reviewed in [Raetz02] and [Whitfield06]). Subsequently, the polymer is believed to be cleaved from the all-trans-dodecaprenyl diphosphate anchor, transported across the periplasm, and excreted into the extracellular space, although this process is not well understood.

Colanic acid biosynthesis has been linked to a cluster of 19 genes, which were named wca [Stevenson96, Stout96]. This gene cluster is tightly regulated by a complex signal transduction cascade governed by the rcs (regulator of capsule synthesis) phosphorelay system [Gottesman85, Majdalani05a].

Subpathways: GDP-L-fucose biosynthesis I (from GDP-D-mannose), GDP-mannose biosynthesis, UDP-α-D-glucuronate biosynthesis (from UDP-glucose), UDP-D-galactose biosynthesis, UDP-glucose biosynthesis

Created 02-Dec-1997 by Pellegrini-Toole A, Marine Biological Laboratory
Revised 29-May-2008 by Caspi R, SRI International
Revised 13-Jun-2008 by Keseler I, SRI International
Revised 15-Aug-2013 by Caspi R, SRI International


Garegg71: Garegg PJ, Lindberg B, Onn T, Sutherland IW (1971). "Comparative structural studies on the M-antigen from Salmonella typhimurium. Escherichia coli and Aerobacter cloacae." Acta Chem Scand 25(6);2103-8. PMID: 4941627

Gottesman85: Gottesman S, Trisler P, Torres-Cabassa A (1985). "Regulation of capsular polysaccharide synthesis in Escherichia coli K-12: characterization of three regulatory genes." J Bacteriol 162(3);1111-9. PMID: 3888955

Grant69: Grant WD, Sutherland IW, Wilkinson JF (1969). "Exopolysaccharide colanic acid and its occurrence in the Enterobacteriaceae." J Bacteriol 100(3);1187-93. PMID: 4902806

Majdalani05a: Majdalani N, Gottesman S (2005). "The Rcs phosphorelay: a complex signal transduction system." Annu Rev Microbiol 59;379-405. PMID: 16153174

Raetz02: Raetz CR, Whitfield C (2002). "Lipopolysaccharide endotoxins." Annu Rev Biochem 71;635-700. PMID: 12045108

Stevenson96: Stevenson G, Andrianopoulos K, Hobbs M, Reeves PR (1996). "Organization of the Escherichia coli K-12 gene cluster responsible for production of the extracellular polysaccharide colanic acid." J Bacteriol 1996;178(16);4885-93. PMID: 8759852

Stout96: Stout V (1996). "Identification of the promoter region for the colanic acid polysaccharide biosynthetic genes in Escherichia coli K-12." J Bacteriol 178(14);4273-80. PMID: 8763957

Whitfield06: Whitfield C (2006). "Biosynthesis and assembly of capsular polysaccharides in Escherichia coli." Annu Rev Biochem 75;39-68. PMID: 16756484

Other References Related to Enzymes, Genes, Subpathways, and Substrates of this Pathway

Adhya71: Adhya S, Schwartz M (1971). "Phosphoglucomutase mutants of Escherichia coli K-12." J Bacteriol 108(2);621-6. PMID: 4942754

Ahn11: Ahn J, Chung BK, Lee DY, Park M, Karimi IA, Jung JK, Lee H (2011). "NADPH-dependent pgi-gene knockout Escherichia coli metabolism producing shikimate on different carbon sources." FEMS Microbiol Lett 324(1);10-6. PMID: 22092758

Al12: Al Mamun AA, Lombardo MJ, Shee C, Lisewski AM, Gonzalez C, Lin D, Nehring RB, Saint-Ruf C, Gibson JL, Frisch RL, Lichtarge O, Hastings PJ, Rosenberg SM (2012). "Identity and function of a large gene network underlying mutagenic repair of DNA breaks." Science 338(6112);1344-8. PMID: 23224554

Albermann01a: Albermann C, Piepersberg W, Wehmeier UF (2001). "Synthesis of the milk oligosaccharide 2'-fucosyllactose using recombinant bacterial enzymes." Carbohydr Res 334(2);97-103. PMID: 11502265

Amor97: Amor PA, Whitfield C (1997). "Molecular and functional analysis of genes required for expression of group IB K antigens in Escherichia coli: characterization of the his-region containing gene clusters for multiple cell-surface polysaccharides." Mol Microbiol 26(1);145-61. PMID: 9383197

Andrianopoulos98: Andrianopoulos K, Wang L, Reeves PR (1998). "Identification of the fucose synthetase gene in the colanic acid gene cluster of Escherichia coli K-12." J Bacteriol 1998;180(4);998-1001. PMID: 9473059

Aoyama94: Aoyama K, Haase AM, Reeves PR (1994). "Evidence for effect of random genetic drift on G+C content after lateral transfer of fucose pathway genes to Escherichia coli K-12." Mol Biol Evol 1994;11(6);829-38. PMID: 7815923

Arabshahi88: Arabshahi A, Flentke GR, Frey PA (1988). "Uridine diphosphate galactose 4-epimerase. pH dependence of the reduction of NAD+ by a substrate analog." J Biol Chem 263(6);2638-43. PMID: 3277958

Arrecubieta94: Arrecubieta C, Lopez R, Garcia E (1994). "Molecular characterization of cap3A, a gene from the operon required for the synthesis of the capsule of Streptococcus pneumoniae type 3: sequencing of mutations responsible for the unencapsulated phenotype and localization of the capsular cluster on the pneumococcal chromosome." J Bacteriol 176(20);6375-83. PMID: 7929009

Barat01: Barat B, Bhattacharyya D (2001). "UDP-galactose 4-epimerase from Escherichia coli: formation of catalytic site during reversible folding." Arch Biochem Biophys 391(2);188-96. PMID: 11437350

Bastin95: Bastin DA, Reeves PR (1995). "Sequence and analysis of the O antigen gene (rfb) cluster of Escherichia coli O111." Gene 1995;164(1);17-23. PMID: 7590310

Bauer91: Bauer AJ, Rayment I, Frey PA, Holden HM (1991). "The isolation, purification, and preliminary crystallographic characterization of UDP-galactose-4-epimerase from Escherichia coli." Proteins 9(2);135-42. PMID: 2008433

Bauer92: Bauer AJ, Rayment I, Frey PA, Holden HM (1992). "The molecular structure of UDP-galactose 4-epimerase from Escherichia coli determined at 2.5 A resolution." Proteins 12(4);372-81. PMID: 1579570

Berger01: Berger E, Arabshahi A, Wei Y, Schilling JF, Frey PA (2001). "Acid-base catalysis by UDP-galactose 4-epimerase: correlations of kinetically measured acid dissociation constants with thermodynamic values for tyrosine 149." Biochemistry 40(22);6699-705. PMID: 11380265

Bhattacharyya99: Bhattacharyya U, Dhar G, Bhaduri A (1999). "An arginine residue is essential for stretching and binding of the substrate on UDP-glucose-4-epimerase from Escherichia coli. Use of a stacked and quenched uridine nucleotide fluorophore as probe." J Biol Chem 274(21);14573-8. PMID: 10329648

Bingham87: Bingham AH, Busby SJ (1987). "Translation of galE and coordination of galactose operon expression in Escherichia coli: effects of insertions and deletions in the non-translated leader sequence." Mol Microbiol 1(1);117-24. PMID: 2838723

Blackburn76: Blackburn P, Ferdinand W (1976). "The concerted inactivation of Escherichia coli uridine diphosphate galactose 4-epimerase by sugar nucleotide together with a free sugar." Biochem J 155(2);225-9. PMID: 779771

Brautaset98: Brautaset T, Petersen S, Valla S (1998). "An experimental study on carbon flow in Escherichia coli as a function of kinetic properties and expression levels of the enzyme phosphoglucomutase." Biotechnol Bioeng 58(2-3);299-302. PMID: 10191405

BRENDA14: BRENDA team (2014). Imported from BRENDA version existing on Aug 2014.

Britton68: Britton HG, Clarke JB (1968). "The mechanism of the phosphoglucomutase reaction. Studies on rabbit muscle phosphoglucomutase with flux techniques." Biochem J 110(2);161-80. PMID: 5726186

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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
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