title: Structural analysis of the sheath of a sheathed bacterium, Leptothrix cholodnii.
abstract: Leptothrix cholodnii is an aerobic sheath-forming bacterium often found in oligotrophic and metal-rich aquatic environments. The sheath of this bacterium was isolated by selectively lysing the cells. Glycine and cysteine were the major amino acids of the sheath. The sheath was readily dissolved in hydrazine, and a polysaccharide substituted with cysteine was recovered from the solution. Galactosamine, glucosamine and galacturonic acid were detected in the hydrazinolysate by gas liquid chromatography analysis. FAB-MS analysis of the hydrazinolysate suggested a sugar sequence of HexN-GalA-HexN-HexN. Methylation linkage analysis revealed the presence of 4-linked GalA, 3-linked HexN and 4-linked HexN. The sulfhydryl groups of the sheath were used for labeling with the fluorogenic reagent, 4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (ABD-F). The labeled sheath (ABD-sheath) was partially hydrolyzed and three fluorescent fragments were purified by HPLC. One of them was identified as ABD-cysteine. The second one was found to be the ABD-cysteine tetramer. Another fragment was indicated to be a pentasaccharide substituted with ABD-cysteine by nuclear magnetic resonance (NMR) analysis. It can be assumed that the polysaccharide and peptide moieties of the sheath are connected by a cysteine residue. NMR analysis of the hydrazinolysate revealed that the polysaccharide moiety of the sheath was constructed from a pentasaccharide repeating unit containing 2-amino-2-deoxygalacturonic acid (GalNA), as shown below. -->4)-alpha-GalNA-(1-->4)-alpha-D-GalN(p)-(1-->4)-alpha-D-GalA(p)-(1-->4)-beta-D-GlcN(p)-(1-->3)-beta-D-GalN(p)-(1-->.
authors.affiliation: Division of Materials Science and Chemical Engineering, Faculty of Engineering, Yokohama National University, Tokiwadai 79-5, Hodogaya, Yokohama 240-8501, Japan. mtake@ynu.ac.jp
authors.forename: Minoru
authors.initials: M
authors.lastname: Takeda
authors.forename: Hiroko
authors.initials: H
authors.lastname: Makita
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Ohno
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nakahara
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Koizumi
mesh_terms: D001688:Biological Products / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry; D005456:Fluorescent Dyes / Q000494:pharmacology; D005688:Galactosamine / Q000737:chemistry; D005944:Glucosamine / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006834:Hydrazines / Q000494:pharmacology; D006868:Hydrolysis; D042743:Leptothrix / Q000378:metabolism*; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008745:Methylation; D010069:Oxadiazoles / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D017434:Protein Structure, Tertiary
chemical_list: D001688:Biological Products; D005456:Fluorescent Dyes; D006603:Hexuronic Acids; D006834:Hydrazines; D008055:Lipids; D010069:Oxadiazoles; D010455:Peptides; D011134:Polysaccharides; D011135:Polysaccharides, Bacterial; C011399:2-amino-2-deoxygalacturonic acid; C029424:hydrazine; C007819:galacturonic acid; D005688:Galactosamine; C046364:4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole; D003545:Cysteine; D005944:Glucosamine; D005998:Glycine