|Gene:||waaU||Accession Numbers: EG11423 (MetaCyc), b3623, ECK3613|
Species: Escherichia coli K-12 substr. MG1655
The lipopolysaccharide of E. coli K-12 consists of two major components: the hydrophobic lipid A moiety inserted into the outer membrane and the phosphorylated core oligosaccharide [Raetz02]. E. coli K-12 does not produce O antigen to attach to the LPS core due to a defect in the rfb gene cluster which can be complemented with genes from a second, independent rfb mutant to produce an O16 type O antigen [Stevenson94]. E. coli K-12 may have two major pathways for LPS biosynthesis. One generates LPS cores suitable for O antigen attachment, and a second generates lipooligosaccharides (LOS) with modifications to the core structure which prevent O antigen attachment [Klena92].
It is also suggested that WaaU may attach GlcNAc to an inner core heptose since a waaU mutant becomes sensitive to phage Br2 [Klena92].
The chromosomal waa region (formerly rfa) contains the major core-oligosaccharide assembly operons in E. coli [Raetz02][Raetz07]. The current nomenclature system was proposed originally in [Reeves96] and [Heinrichs98] and followed thereafter.
|Map Position: [3,796,262 <- 3,797,335]|
Molecular Weight of Polypeptide: 41.729 kD (from nucleotide sequence)
Unification Links: ASAP:ABE-0011851 , CGSC:33791 , DIP:DIP-10672N , EchoBASE:EB1393 , EcoGene:EG11423 , EcoliWiki:b3623 , Entrez-gene:948147 , Mint:MINT-1231283 , ModBase:P27242 , OU-Microarray:b3623 , PortEco:waaU , PR:PRO_000024215 , Protein Model Portal:P27242 , RefSeq:NP_418080 , RegulonDB:EG11423 , String:511145.b3623 , UniProt:P27242
|Biological Process:||GO:0009244 - lipopolysaccharide core region biosynthetic process
GO:0008152 - metabolic process [GOA01]
GO:0009103 - lipopolysaccharide biosynthetic process [UniProtGOA11]
|Molecular Function:||GO:0016757 - transferase activity, transferring glycosyl groups
[UniProtGOA11, GOA01, Klena92]
GO:0008917 - lipopolysaccharide N-acetylglucosaminyltransferase activity [GOA01a]
GO:0016740 - transferase activity [UniProtGOA11]
|Cellular Component:||GO:0016020 - membrane [UniProtGOA11a, UniProtGOA11]|
|MultiFun Terms:||cell structure → surface antigens (ECA, O antigen of LPS)|
|metabolism → biosynthesis of macromolecules (cellular constituents) → lipopolysaccharide → core region|
EC Number: 18.104.22.168
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
Reversibility of this reaction is unspecified.
Enzymatic reaction of: Lipid A-core heptosyl transferase (lipopolysaccharide core biosynthesis; heptosyl transferase IV; probably hexose transferase)
EC Number: 2.4.-.-
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.
The reaction is favored in the direction shown.
10/20/97 Gene b3623 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG11423; confirmed by SwissProt match.
Heinrichs98: Heinrichs DE, Yethon JA, Whitfield C (1998). "Molecular basis for structural diversity in the core regions of the lipopolysaccharides of Escherichia coli and Salmonella enterica." Mol Microbiol 30(2);221-32. PMID: 9791168
Klena92: Klena JD, Ashford RS, Schnaitman CA (1992). "Role of Escherichia coli K-12 rfa genes and the rfp gene of Shigella dysenteriae 1 in generation of lipopolysaccharide core heterogeneity and attachment of O antigen." J Bacteriol 174(22);7297-307. PMID: 1385388
Klena92a: Klena JD, Pradel E, Schnaitman CA (1992). "Comparison of lipopolysaccharide biosynthesis genes rfaK, rfaL, rfaY, and rfaZ of Escherichia coli K-12 and Salmonella typhimurium." J Bacteriol 174(14);4746-52. PMID: 1624462
Reeves96: Reeves PR, Hobbs M, Valvano MA, Skurnik M, Whitfield C, Coplin D, Kido N, Klena J, Maskell D, Raetz CR, Rick PD (1996). "Bacterial polysaccharide synthesis and gene nomenclature." Trends Microbiol 4(12);495-503. PMID: 9004408
Stevenson94: Stevenson G, Neal B, Liu D, Hobbs M, Packer NH, Batley M, Redmond JW, Lindquist L, Reeves P (1994). "Structure of the O antigen of Escherichia coli K-12 and the sequence of its rfb gene cluster." J Bacteriol 1994;176(13);4144-56. PMID: 7517391
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