title: Structural determination of the lipo-chitin oligosaccharide nodulation signals produced by Rhizobium giardinii bv. giardinii H152.
abstract: Rhizobium giardinii bv. giardinii is a microsymbiont of plants of the genus Phaseolus and produces extracellular signal molecules that are able to induce deformation of root hairs and nodule organogenesis. We report here the structures of seven lipochitooligosaccharide (LCO) signal molecules secreted by R. giardinii bv. giardinii H152. Six of them are pentamers of GlcNAc carrying C 16:0, C 18:0, C 20:0 and C 18:1 fatty acyl chains on the non-reducing terminal residue. Four are sulfated at C-6 of the reducing terminal residue and one is acetylated in the same position. Six of them are N-methylated on the non-reducing GlcN residue and all the nodulation factors are carbamoylated on C-6 of the non-reducing terminal residue. The structures were determined using monosaccharide composition and methylation analyses, 1D- and 2D-NMR experiments and a range of mass spectrometric techniques. The position of the carbamoyl substituent on the non-reducing glucosamine residue was determined using a CID-MSMS experiment and an HMBC experiment.
authors.affiliation: Departamento de Química Orgánica, Facultad de Química, Universidad de Sevilla, 41071, Sevilla, Spain.
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: Soria-Díaz
authors.forename: Pilar
authors.initials: P
authors.lastname: Tejero-Mateo
authors.forename: José L
authors.initials: JL
authors.lastname: Espartero
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rodríguez-Carvajal
authors.forename: Belén
authors.initials: B
authors.lastname: Morón
authors.forename: Carolina
authors.initials: C
authors.lastname: Sousa
authors.forename: Manuel
authors.initials: M
authors.lastname: Megías
authors.forename: Noelle
authors.initials: N
authors.lastname: Amarger
authors.forename: Jane
authors.initials: J
authors.lastname: Thomas-Oates
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Gil-Serrano
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005227:Fatty Acids / Q000032:analysis; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D009005:Monosaccharides / Q000032:analysis; D012231:Rhizobium / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D008070:Lipopolysaccharides; D009005:Monosaccharides; C478179:Nod factor, Rhizobium giardinii; C023023:lipid-linked oligosaccharides