Structural elucidation of polysaccharide part of glycoconjugate from Treponema medium ATCC 700293

Abstract

Glycoconjugates are distributed on the cell surfaces of some small-sized treponemes and have been reported to be completely different from lipopolysaccharides. We separated a glycoconjugate fraction from Treponema medium ATCC 700293, a medium-sized oral spirochete, to assess its immunobiological activities and elucidate the chemical structure of its polysaccharide part using phenol/water extraction, hydrophobic chromatography, and gel filtration. The glycoconjugate showed negligible or weak endotoxic and immunobiological properties. The chemical structure of the polysaccharide part was shown by two-dimensional NMR and MALDI-TOF-MS to be a tetrasaccharide backbone with two amino acids: [→4)β-D-GlcpNAc3NAcA(1→4)β-D-ManpNAc3NA Orn(1→3)β-D-GlcpNAc(1→3)α-D-Fucp4NAsp(1→] where G1cNAc3NAcA is 2,3-diacetamido-2,3-dideoxy-glucuronic acid, ManNAc3NAOrn is Nδ-(2-acetamido3-ammo-2,3-dideoxymannuronyl)ornithine, and Fuc4NAsp is 4-(α-aspartyl)amino-4,6-dideoxygalactose.