title: Three N-Glycosylation Sites of Human Acetylcholinesterase Shares Similar Glycan Composition.
abstract: Acetylcholinesterase (AChE; EC 3.1.1.7) is a glycoprotein possessing three conserved N-linked glycosylation sites in mammalian species, locating at 296, 381, and 495 residues of the human sequence. Several lines of evidence demonstrated that N-glycosylation of AChE affected the enzymatic activity, as well as its biosynthesis. In order to determine the role of three N-glycosylation sites in AChE activity and glycan composition, the site-directed mutagenesis of N-glycosylation sites in wild-type human AChE(T) sequence was employed to generate the single-site mutants (i.e., AChE(T) (N296Q), AChET (N381Q), and AChE(T) (N495Q)) and all site mutant (i.e., AChE(T) (3N→3Q)). The mutation did not affect AChE protein expression in the transfected cells. The mutants, AChE(T) (3N→3Q) and AChE(T) (N381Q), showed very minimal enzymatic activity, while the other mutants showed reduced activity. By binding to lectins, Con A, and SNA, the glycosylation profile was revealed in those mutated AChE. The binding affinity with lectins showed no significant difference between various N-glycosylation mutants, which suggested that similar glycan composition should be resulted from different N-glycosylation sites. Although the three glycosylation sites within AChE sequence have different extent in affecting the enzymatic activity, their glycan compositions are very similar.
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
authors.forename: Miranda L
authors.initials: ML
authors.lastname: Xu
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
authors.forename: Wilson K W
authors.initials: WK
authors.lastname: Luk
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
authors.forename: Kei M
authors.initials: KM
authors.lastname: Lau
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
authors.forename: Cathy W C
authors.initials: CW
authors.lastname: Bi
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
authors.forename: Anthony W M
authors.initials: AW
authors.lastname: Cheng
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
authors.forename: Amy G W
authors.initials: AG
authors.lastname: Gong
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
authors.forename: Huangquan
authors.initials: H
authors.lastname: Lin
authors.affiliation: Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China. botsim@ust.hk.
authors.forename: Karl W K
authors.initials: KW
authors.lastname: Tsim
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019943:Amino Acid Substitution; D006031:Glycosylation; D057809:HEK293 Cells; D006801:Humans; D037102:Lectins / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry*; D011485:Protein Binding; D011499:Protein Processing, Post-Translational
chemical_list: D037102:Lectins; D011134:Polysaccharides; D000110:Acetylcholinesterase
keywords: AChE; Lectin; Molecular form; N-glycosylation sites; PRiMA