title: Protein glycosylation in Helicobacter pylori: beyond the flagellins?
abstract: Glycosylation of flagellins by pseudaminic acid is required for virulence in Helicobacter pylori. We demonstrate that, in H. pylori, glycosylation extends to proteins other than flagellins and to sugars other than pseudaminic acid. Several candidate glycoproteins distinct from the flagellins were detected via ProQ-emerald staining and DIG- or biotin- hydrazide labeling of the soluble and outer membrane fractions of wild-type H. pylori, suggesting that protein glycosylation is not limited to the flagellins. DIG-hydrazide labeling of proteins from pseudaminic acid biosynthesis pathway mutants showed that the glycosylation of some glycoproteins is not dependent on the pseudaminic acid glycosylation pathway, indicating the existence of a novel glycosylation pathway. Fractions enriched in glycoprotein candidates by ion exchange chromatography were used to extract the sugars by acid hydrolysis. High performance anion exchange chromatography with pulsed amperometric detection revealed characteristic monosaccharide peaks in these extracts. The monosaccharides were then identified by LC-ESI-MS/MS. The spectra are consistent with sugars such as 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (Pse5Ac7Ac) previously described on flagellins, 5-acetamidino-7-acetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (Pse5Am7Ac), bacillosamine derivatives and a potential legionaminic acid derivative (Leg5AmNMe7Ac) which were not previously identified in H. pylori. These data open the way to the study of the mechanism and role of protein glycosylation on protein function and virulence in H. pylori.
authors: Infectious Diseases Research Group, Department of Microbiology and Immunology, The University of Western Ontario, London, Ontario, Canada.
authors: Patrick S
authors: PS
authors: Hopf
authors: Rachel S
authors: RS
authors: Ford
authors: Najwa
authors: N
authors: Zebian
authors: Alexandra
authors: A
authors: Merkx-Jacques
authors: Somalinga
authors: S
authors: Vijayakumar
authors: Dinath
authors: D
authors: Ratnayake
authors: Jacqueline
authors: J
authors: Hayworth
authors: Carole
authors: C
authors: Creuzenet
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D006031:Glycosylation; D016480:Helicobacter pylori / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D014774:Virulence
chemical_list: C502287:5,7-diacetamido-3,5,7,9-tetradeoxynon-2-ulosonic acid; D001426:Bacterial Proteins; D012794:Sialic Acids