title: Identification of the Mycobacterium marinum Apa antigen O-mannosylation sites reveals important glycosylation variability with the M. tuberculosis Apa homologue.
abstract: The 45/47 kDa Apa, an immuno-dominant antigen secreted by Mycobacterium tuberculosis is O-mannosylated at multiple sites. Glycosylation of Apa plays a key role in colonization and invasion of the host cells by M. tuberculosis through interactions of Apa with the host immune system C-type lectins. Mycobacterium marinum (M.ma) a fish pathogen, phylogenetically close to M. tuberculosis, induces a granulomatous response with features similar to those described for M. tuberculosis in human. Although M.ma possesses an Apa homologue, its glycosylation status is unknown, and whether this represents a crucial element in the pathophysiology induced by M.ma remains to be addressed. To this aim, we have identified two concanavalin A-reactive 45/47 kDa proteins from M.ma, which have been further purified by a two-step anion exchange chromatography process. Advanced liquid chromatography-nanoESI mass spectrometry-based proteomic analyses of peptides, derived from either tryptic digestion alone or in combination with the Asp-N endoproteinase, established that M.ma Apa possesses up to seven distinct O-mannosylated sites with mainly single mannose substitutions, which can be further extended at the Ser/Thr/Pro rich region near the N-terminus. This opens the way to further studies focussing on the involvement and biological functions of Apa O-mannosylation using the M.ma/zebrafish model.
authors: Université Lille1, Unité de Glycobiologie Structurale et Fonctionnelle, UGSF, F-59650 Villeneuve d'Ascq, France.
authors: Bernadette
authors: B
authors: Coddeville
authors: Sz-Wei
authors: SW
authors: Wu
authors: Emeline
authors: E
authors: Fabre
authors: Colette
authors: C
authors: Brassart
authors: Yoann
authors: Y
authors: Rombouts
authors: Adeline
authors: A
authors: Burguière
authors: Laurent
authors: L
authors: Kremer
authors: Kay-Hooi
authors: KH
authors: Khoo
authors: Elisabeth
authors: E
authors: Elass-Rochard
authors: Yann
authors: Y
authors: Guérardel
mesh_terms: D000595:Amino Acid Sequence; D000942:Antigens, Bacterial / Q000737:chemistry* / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry*; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D006031:Glycosylation; D008358:Mannose / Q000378:metabolism*; D019910:Mycobacterium marinum / Q000276:immunology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D006023:Glycoproteins; D008358:Mannose