title: Against the rules: a marine bacterium, Loktanella rosea, possesses a unique lipopolysaccharide.
abstract: Bacteria are an inimitable source of new glyco-structures potentially useful in medicinal and environmental chemistry. Lipopolysaccharides (LPS; endotoxins) are the major components of the outer membrane of Gram-negative bacteria; being exposed toward the external environment they can undergo structural changes and thus, they often possess peculiar chemical features that allow them to thrive in harsh chemical and physical environments. Marine bacteria have evolved and adapted over millions of years in order to succeed in different environments, finding a niche for their survival characterized by severe physical or chemical parameters. The present work focuses on the structural investigation of the LPS from Loktanella rosea, a marine Gram-negative bacterium. Through chemical analysis, 2D nuclear magnetic resonance and matrix-assisted laser desorption ionization mass spectrometry investigations, a unique LPS carbohydrate backbone has been defined. The lipid A skeleton consists of a trisaccharide backbone lacking the typical phosphate groups and is characterized by two beta-glucosamines and an alpha-galacturonic acid. The core region is built up of three ulosonic acids, with two 3-deoxy-d-manno-oct-2-ulopyranosonic acid residues, one of which is carrying a neuraminic acid. This carbohydrate structure is an exceptional variation from the typical architectural skeleton of endotoxins which consequently implies a very different biosynthesis.
authors.affiliation: Dipartimento di Chimica Organica e Biochimica, Università di Napoli "Federico II", Complesso Universitario Monte S. Angelo, Via Cintia 4, 80126 Napoli, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Ieranò
authors.forename: Alba
authors.initials: A
authors.lastname: Silipo
authors.forename: Evgeny L
authors.initials: EL
authors.lastname: Nazarenko
authors.forename: Raisa P
authors.initials: RP
authors.lastname: Gorshkova
authors.forename: Elena P
authors.initials: EP
authors.lastname: Ivanova
authors.forename: Domenico
authors.initials: D
authors.lastname: Garozzo
authors.forename: Luisa
authors.initials: L
authors.lastname: Sturiale
authors.forename: Rosa
authors.initials: R
authors.lastname: Lanzetta
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.forename: Antonio
authors.initials: A
authors.lastname: Molinaro
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D008070:Lipopolysaccharides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D041902:Rhodobacteraceae / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D008070:Lipopolysaccharides