title: Subunit structure of the galactose and N-acetyl-D-galactosamine-inhibitable adherence lectin of Entamoeba histolytica.
abstract: The galactose and N-acetyl-D-galactosamine-inhibitable adherence lectin of Entamoeba histolytica is a cell surface protein which mediates parasite adherence to human colonic mucus, colonic epithelial cells, and other target cells. The amebic lectin was purified in 100-micrograms quantities from detergent-solubilized trophozoites by monoclonal antibody affinity chromatography. The adherence lectin was purified 500-fold as judged by radioimmunoassay. The nonreduced lectin had a molecular mass of 260 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an isoelectric point of pH 6.2. The amebic lectin reduced with beta-mercaptoethanol consisted of 170- and 35-kDa subunits. Both subunits could be labeled on the cell surface with 125I, and both were metabolically labeled with [3H]glucosamine. The amino termini of the subunits had unique amino acid sequences, and polyclonal antisera to the heavy subunit did not cross-react with the light subunit. The yield of phenylthiohydantoin derivatives from the second and third positions in the sequence of the heavy and light subunits gave a molar ratio of one 170- to one 35-kDa subunit. Antibodies directed to the heavy subunit inhibited amebic adherence to Chinese hamster ovary cells by 100%, suggesting that the heavy subunit is predominantly responsible for mediating amebic adherence.
authors.affiliation: Department of Medicine, University of Virginia School of Medicine, Charlottesville 22908.
authors.forename: W A
authors.initials: WA
authors.lastname: Petri
authors.forename: M D
authors.initials: MD
authors.lastname: Chapman
authors.forename: T
authors.initials: T
authors.lastname: Snodgrass
authors.forename: B J
authors.initials: BJ
authors.lastname: Mann
authors.forename: J
authors.initials: J
authors.lastname: Broman
authors.forename: J I
authors.initials: JI
authors.lastname: Ravdin
mesh_terms: D000116:Acetylgalactosamine; D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D002460:Cell Line; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004748:Entamoeba histolytica / Q000032:analysis*; D005688:Galactosamine / Q000031:analogs & derivatives; D005690:Galactose; D037102:Lectins / Q000302:isolation & purification; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D008970:Molecular Weight
chemical_list: D000906:Antibodies; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D037102:Lectins; D046911:Macromolecular Substances; D005688:Galactosamine; D000116:Acetylgalactosamine; D005690:Galactose