Open AccessSequence of a cysteine-rich galactose-specific lectin of Entamoeba histolytica.
Author(s) -
Barbara J. Mann,
Bruce E. Torian,
Thomas S. Vedvick,
William A. Petri
Publication year - 1991
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.88.8.3248
Subject(s) - entamoeba histolytica , lectin , peptide sequence , cd69 , biochemistry , protein subunit , biology , glycosylation , mucin , c type lectin , cysteine , masp1 , microbiology and biotechnology , amino acid , extracellular , tunicamycin , glycoprotein , protease , serine protease , gene , enzyme , cytotoxic t cell , unfolded protein response , il 2 receptor , in vitro
Entamoeba histolytica trophozoites adhere to human colonic mucins and epithelial cells by a cell surface galactose-specific lectin. This lectin, which is composed of two subunits linked by disulfide bonds, has been shown to be a protective antigen in an animal model of amebiasis. We have determined the sequence of the mature form of the 170-kDa heavy subunit from cDNA clones and PCR-amplified fragments. The heavy subunit sequence consisted of a putative extracellular domain containing 1209 amino acids with 16 potential sites for N-linked glycosylation, a 26-amino acid hydrophobic region, and a 41-amino acid cytoplasmic tail. The presence of N-linked oligosaccharides was confirmed by culturing amebae with tunicamycin, which resulted in a decrease in the heavy subunit molecular mass to 160 kDa and a loss of lectin activity. The extracellular domain was remarkable for an extensive cysteine-rich domain that shared identify with similar regions of several other cell surface proteins and appeared to confer protease resistance to the subunit.