title: The Giardia intestinalis filamentous cyst wall contains a novel beta(1-3)-N-acetyl-D-galactosamine polymer: a structural and conformational study.
abstract: Assembly of a protective cyst wall by Giardia is essential for the survival of the parasite outside the host intestine and for transmission among susceptible hosts. The structure of the G. intestinalis filamentous cyst wall was studied by chemical methods, mass spectrometry, and (1)H nuclear magnetic resonance spectroscopy. Isolated cyst wall material contains carbohydrate and protein in a ratio of 3:2 (w/w), and the carbohydrate moiety is composed of a beta(1-3)-N-acetyl-D-galactopyranosamine homopolymer. Conformational analysis by molecular dynamics and persistence length calculations of GalNAc oligomers in solution demonstrated a flexible structure consisting of left- and right-handed helical elements. It is most likely that in the solid state, the polysaccharide forms ordered helices or possibly multiple helical structures having strong interchain interactions. The highly insoluble nature of the Giardia cyst wall must be due to these strong interchain interactions and, probably, a strong association between the carbohydrate and the protein moiety.
authors.affiliation: Bijvoet Center, Department of Bio-Organic Chemistry, Section of Glycoscience and Biocatalysis, Utrecht University, Padualaan 8, NL-3584 CH Utrecht, The Netherlands.
authors.forename: Gerrit J
authors.initials: GJ
authors.lastname: Gerwig
authors.forename: J Albert
authors.initials: JA
authors.lastname: van Kuik
authors.forename: Bas R
authors.initials: BR
authors.lastname: Leeflang
authors.forename: Johannis P
authors.initials: JP
authors.lastname: Kamerling
authors.forename: Johannes F G
authors.initials: JF
authors.lastname: Vliegenthart
authors.forename: Craig D
authors.initials: CD
authors.lastname: Karr
authors.forename: Edward L
authors.initials: EL
authors.lastname: Jarroll
mesh_terms: D000818:Animals; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D002236:Carbohydrate Conformation; D016829:Giardia lamblia / Q000737:chemistry* / Q000166:cytology; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008958:Models, Molecular
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D001704:Biopolymers; C016467:Thomsen-Friedenreich antigen