title: Flagellin glycans from two pathovars of Pseudomonas syringae contain rhamnose in D and L configurations in different ratios and modified 4-amino-4,6-dideoxyglucose.
abstract: Flagellins from Pseudomonas syringae pv. glycinea race 4 and Pseudomonas syringae pv. tabaci 6605 have been found to be glycosylated. Glycosylation of flagellin is essential for bacterial virulence and is also involved in the determination of host specificity. Flagellin glycans from both pathovars were characterized, and common sites of glycosylation were identified on six serine residues (positions 143, 164, 176, 183, 193, and 201). The structure of the glycan at serine 201 (S201) of flagellin from each pathovar was determined by sugar composition analysis, mass spectrometry, and (1)H and (13)C nuclear magnetic resonance spectroscopy. These analyses showed that the S201 glycans from both pathovars were composed of a common unique trisaccharide consisting of two rhamnosyl (Rha) residues and one modified 4-amino-4,6-dideoxyglucosyl (Qui4N) residue, beta-D-Quip4N(3-hydroxy-1-oxobutyl)2Me-(1-->3)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap. Furthermore, mass analysis suggests that the glycans on each of the six serine residues are composed of similar trisaccharide units. Determination of the enantiomeric ratio of Rha from the flagellin proteins showed that flagellin from P. syringae pv. tabaci 6605 consisted solely of L-Rha, whereas P. syringae pv. glycinea race 4 flagellin contained both L-Rha and D-Rha at a molar ratio of about 4:1. Taking these findings together with those from our previous study, we conclude that these flagellin glycan structures may be important for the virulence and host specificity of P. syringae.
authors.affiliation: National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki 305-8602, Japan. kasumit@affrc.go.jp
authors.forename: Kasumi
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ono
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Yoshida
authors.forename: Tadashi
authors.initials: T
authors.lastname: Ishii
authors.forename: Etsuko
authors.initials: E
authors.lastname: Katoh
authors.forename: Fumiko
authors.initials: F
authors.lastname: Taguchi
authors.forename: Ryuji
authors.initials: R
authors.lastname: Miki
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Murata
authors.forename: Hanae
authors.initials: H
authors.lastname: Kaku
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ichinose
mesh_terms: D002240:Carbohydrate Sequence; D005408:Flagellin / Q000737:chemistry / Q000378:metabolism*; D005798:Genes, Bacterial; D006031:Glycosylation; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009154:Mutation; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D044224:Pseudomonas syringae / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D012210:Rhamnose / Q000737:chemistry / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013237:Stereoisomerism; D014774:Virulence / Q000235:genetics
chemical_list: D011134:Polysaccharides; D005408:Flagellin; D012210:Rhamnose