title: The role of lic2B in lipopolysaccharide biosynthesis in Haemophilus influenzae strain Eagan.
abstract: Lipopolysaccharide (LPS) biosynthesis in Haemophilus influenzae involves genes from the lic2 locus that are required for chain extension from the middle heptose (HepII) of the conserved triheptosyl inner-core moiety. Lic2C initiates the process by attaching the first glucose to HepII, but the gene encoding for the enzyme adding the next β-D-Glcp- is uncharacterized. Lic2B is the candidate glucosyltransferase; however, in previous investigations, mutation of lic2B resulted in no hexose extension from HepII, likely due to a polar effect on the lic2C gene. In this study we complemented a lic2B knock-out mutant of H. influenzae strain Eagan with a functional lic2C gene and investigated its LPS by mass spectrometry and 2D NMR spectroscopy. Lic2B was found to encode a glucosyltransferase responsible for the linkage of β-D-Glcp-(1→4)-α-D-Glcp-(1→ extending from O-3 of the central heptose of the triheptosyl inner-core moiety, l-α-D-Hepp-(1→2)-[PEtn→6]-l-α-D-Hepp-(1→3)-l-α-D-Hepp-(1→5)-[PPEtn→4]-α-Kdo-(2→6)-lipid A.
authors.affiliation: Clinical Research Centre, Karolinska Institutet, Novum, S-141 86 Huddinge, Sweden.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Twelkmeyer
authors.forename: Mary E
authors.initials: ME
authors.lastname: Deadman
authors.forename: Ehsanul
authors.initials: E
authors.lastname: Haque
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.forename: Derek W
authors.initials: DW
authors.lastname: Hood
authors.forename: Elke K H
authors.initials: EK
authors.lastname: Schweda
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002240:Carbohydrate Sequence; D005964:Glucosyltransferases / Q000378:metabolism; D006192:Haemophilus Infections / Q000378:metabolism / Q000473:pathology*; D006193:Haemophilus influenzae / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008070:Lipopolysaccharides / Q000096:biosynthesis* / Q000737:chemistry; D013058:Mass Spectrometry; D008969:Molecular Sequence Data
chemical_list: D001426:Bacterial Proteins; D008070:Lipopolysaccharides; C104912:lic2B protein, Haemophilus influenzae; D005964:Glucosyltransferases