title: Structure characterization of an exopolysaccharide produced by Bifidobacterium animalis RH.
abstract: An exopolysaccharide fraction (EPSb) produced by Bifidobacterium animalis RH isolated from the feces of centenarians was purified to illustrate its structure and conformational characterization. Results from Fourier-transform infrared spectrometry, gel permeation chromatography, high-pH anion-exchange chromatography with pulsed amperometric detection, periodate oxidation and Smith degradation, methylation and gas chromatography-mass spectrometry, and nuclear magnetic response analysis indicated that EPSb (M(w)=21.3 kDa) was composed of rhamnose (Rha), arabinose (Ara), galactose (Gal), glucose (Glc), and mannose (Man) in a molar ratio of 0.4:0.3:1.6:0.8:1.2. This compound had a backbone of (1→3,4)-linked Man, (1→4)-linked Rha, (1→4)-linked Gal, and (1→4)-linked Glc. It was branched with Gal and terminated with Gal and Glc residues. The molecular structure of EPSb was observed via atomic force microscopy. EPSb showed spherical lumps and a ring-like network. Conformational analysis revealed the non-triple helical conformation of EPSb.
authors.affiliation: Key Lab of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
authors.forename: Nan
authors.initials: N
authors.lastname: Shang
authors.forename: Rihua
authors.initials: R
authors.lastname: Xu
authors.forename: Pinglan
authors.initials: P
authors.lastname: Li
mesh_terms: D001644:Bifidobacterium / Q000378:metabolism*; D002236:Carbohydrate Conformation; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis* / Q000737:chemistry*
chemical_list: D011135:Polysaccharides, Bacterial