title: Purification and characterization of phosphonoglycans from Glycomyces sp. strain NRRL B-16210 and Stackebrandtia nassauensis NRRL B-16338.
abstract: Two related actinomycetes, Glycomyces sp. strain NRRL B-16210 and Stackebrandtia nassauensis NRRL B-16338, were identified as potential phosphonic acid producers by screening for the gene encoding phosphoenolpyruvate (PEP) mutase, which is required for the biosynthesis of most phosphonates. Using a variety of analytical techniques, both strains were subsequently shown to produce phosphonate-containing exopolysaccharides (EPS), also known as phosphonoglycans. The phosphonoglycans were purified by sequential organic solvent extractions, methanol precipitation, and ultrafiltration. The EPS from the Glycomyces strain has a mass of 40 to 50 kDa and is composed of galactose, xylose, and five distinct partially O-methylated galactose residues. Per-deutero-methylation analysis indicated that galactosyl residues in the polysaccharide backbone are 3,4-linked Gal, 2,4-linked 3-MeGal, 2,3-linked Gal, 3,6-linked 2-MeGal, and 4,6-linked 2,3-diMeGal. The EPS from the Stackebrandtia strain is comprised of glucose, galactose, xylose, and four partially O-methylated galactose residues. Isotopic labeling indicated that the O-methyl groups in the Stackebrandtia phosphonoglycan arise from S-adenosylmethionine. The phosphonate moiety in both phosphonoglycans was shown to be 2-hydroxyethylphosphonate (2-HEP) by (31)P nuclear magnetic resonance (NMR) and mass spectrometry following strong acid hydrolysis of the purified molecules. Partial acid hydrolysis of the purified EPS from Glycomyces yielded 2-HEP in ester linkage to the O-5 or O-6 position of a hexose and a 2-HEP mono(2,3-dihydroxypropyl)ester. Partial acid hydrolysis of Stackebrandtia EPS also revealed the presence of 2-HEP mono(2,3-dihydroxypropyl)ester. Examination of the genome sequences of the two strains revealed similar pepM-containing gene clusters that are likely to be required for phosphonoglycan synthesis.
authors.affiliation: Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Yu
authors.forename: Neil P J
authors.initials: NP
authors.lastname: Price
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Evans
authors.forename: William W
authors.initials: WW
authors.lastname: Metcalf
mesh_terms: D000192:Actinomycetales / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002240:Carbohydrate Sequence; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D008970:Molecular Weight; D063065:Organophosphonates / Q000378:metabolism*; D017875:Phosphotransferases (Phosphomutases) / Q000235:genetics / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D063065:Organophosphonates; D011135:Polysaccharides, Bacterial; D017875:Phosphotransferases (Phosphomutases); C057167:phosphoenolpyruvate mutase