title: Structural and genetic characterization of the Shigella boydii type 18 O antigen.
abstract: Shigella strains are important human pathogens and are normally identified by their O antigens. O antigen is an essential part of the lipopolysaccharide present in the outer membrane of Gram-negative bacteria and plays a role in pathogenicity. Structural and genetic organization of the Shigella boydii type 18 O antigen was investigated. As judged by sugar and methylation analyses and NMR spectroscopy data, the O antigen has a linear pentasaccharide repeating unit (O unit), which consists of three L-rhamnose residues, and one residue each of D-galacturonic acid (D-GalA) and N-acetylgalactosamine (D-GalNAc), and the following structure of the O unit was established. -->3)-beta-L-Rhap-(1-->4)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap-(1-->2)-alpha-D-GalpA-(1-->3)-alpha-D-GalpNAc-(1--> The O antigen gene cluster of S. boydii type 18, which contains nine open reading frames (ORFs), was found between galF and gnd. Based on homology, all of the ORFs were identified as O antigen synthesis genes, involved in the synthesis of rhamnose, transfer of sugars, and processing of O unit. Genes specific for S. boydii type 18 were identified, which can be potentially used for the development of a PCR-based assay for the identification and detection of this strain.
authors.affiliation: TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin 300457, PR China.
authors.forename: Lu
authors.initials: L
authors.lastname: Feng
authors.forename: Sof'ya N
authors.initials: SN
authors.lastname: Senchenkova
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Alexander S
authors.initials: AS
authors.lastname: Shashkov
authors.forename: Bin
authors.initials: B
authors.lastname: Liu
authors.forename: Sergei D
authors.initials: SD
authors.lastname: Shevelev
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.forename: Yuriy A
authors.initials: YA
authors.lastname: Knirel
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
mesh_terms: D000107:Acetylation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000096:biosynthesis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D008401:Gas Chromatography-Mass Spectrometry; D023061:Gene Order; D005798:Genes, Bacterial / Q000235:genetics; D016695:Glycosyltransferases / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D019081:O Antigens / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012761:Shigella boydii / Q000235:genetics* / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D004269:DNA, Bacterial; D019081:O Antigens; D016695:Glycosyltransferases