title: Diversity within the O-linked protein glycosylation systems of acinetobacter species.
abstract: The opportunistic human pathogen Acinetobacter baumannii is a concern to health care systems worldwide because of its persistence in clinical settings and the growing frequency of multiple drug resistant infections. To combat this threat, it is necessary to understand factors associated with disease and environmental persistence of A. baumannii. Recently, it was shown that a single biosynthetic pathway was responsible for the generation of capsule polysaccharide and O-linked protein glycosylation. Because of the requirement of these carbohydrates for virulence and the non-template driven nature of glycan biogenesis we investigated the composition, diversity, and properties of the Acinetobacter glycoproteome. Utilizing global and targeted mass spectrometry methods, we examined 15 strains and found extensive glycan diversity in the O-linked glycoproteome of Acinetobacter. Comparison of the 26 glycoproteins identified revealed that different A. baumannii strains target similar protein substrates, both in characteristics of the sites of O-glycosylation and protein identity. Surprisingly, glycan micro-heterogeneity was also observed within nearly all isolates examined demonstrating glycan heterogeneity is a widespread phenomena in Acinetobacter O-linked glycosylation. By comparing the 11 main glycoforms and over 20 alternative glycoforms characterized within the 15 strains, trends within the glycan utilized for O-linked glycosylation could be observed. These trends reveal Acinetobacter O-linked glycosylation favors short (three to five residue) glycans with limited branching containing negatively charged sugars such as GlcNAc3NAcA4OAc or legionaminic/pseudaminic acid derivatives. These observations suggest that although highly diverse, the capsule/O-linked glycan biosynthetic pathways generate glycans with similar characteristics across all A. baumannii.
authors.affiliation: From the ‡Centre for High-Throughput Biology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada;
authors.forename: Nichollas E
authors.initials: NE
authors.lastname: Scott
authors.affiliation: §Alberta Glycomics Centre and Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada;
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Kinsella
authors.affiliation: ¶Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, 5000, Denmark;
authors.forename: Alistair V G
authors.initials: AV
authors.lastname: Edwards
authors.affiliation: ¶Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, 5000, Denmark;
authors.forename: Martin R
authors.initials: MR
authors.lastname: Larsen
authors.affiliation: ‖Thermo Fisher Scientific, San Jose, California 95134.
authors.forename: Sucharita
authors.initials: S
authors.lastname: Dutta
authors.affiliation: ‖Thermo Fisher Scientific, San Jose, California 95134.
authors.forename: Julian
authors.initials: J
authors.lastname: Saba
authors.affiliation: From the ‡Centre for High-Throughput Biology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada;
authors.forename: Leonard J
authors.initials: LJ
authors.lastname: Foster
authors.affiliation: §Alberta Glycomics Centre and Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada; mfeldman@ualberta.ca.
authors.forename: Mario F
authors.initials: MF
authors.lastname: Feldman
mesh_terms: D000150:Acinetobacter / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002853:Chromatography, Liquid; D006020:Glycopeptides / Q000378:metabolism; D006031:Glycosylation; D011134:Polysaccharides / Q000378:metabolism*; D053719:Tandem Mass Spectrometry
chemical_list: D001426:Bacterial Proteins; D006020:Glycopeptides; D011134:Polysaccharides