文献类型： 外文期刊

作者： Clark, TG ¹ ; Lin, TL ² ; Jackwood, DA ² ; Sherrill, J ² ; Lin, YK ² ; Dickerson, HW ² ;

作者机构： 1.Cornell Univ, NYSCVM, Dept Microbiol & Immunol, Ithaca, NY 14853 USA

2.Cornell Univ, NYSCVM, Dept Microbiol & Immunol, Ithaca, NY 14853 USA; Fujian Acad Agr Sci, Bioengn Lab, Fuzhou 350003, Peoples R China; Univ Georgia, Coll Vet Med, Dept Med Microbiol, Athens, GA 30602 USA

关键词： Giardia VSPs;GPI-linked protein;Ichthyophthirius;immobilization antigen;zinc fingers

期刊名称：GENE （ 影响因子：3.688； 五年影响因子：3.329 ）

ISSN： 0378-1119

年卷期： 1999 年 229 卷 1-2 期

页码：

收录情况： SCI

摘要： Immobilization antigens are highly abundant surface membrane proteins that coat the surface of hymenostomatid ciliates. While their function is unknown, recent studies with the common fish parasite, Ichthyophthirius multifiliis, suggest their involvement in a novel mechanism of humoral immunity involving an effect of antibody on parasite behavior. To gain further insight into the nature of these proteins, we have cloned a gene encoding the 48 kDa i-antigen of I. multifiliis. Analysis of the gene (designated IAG48[G1]) reveals a single, uninterrupted reading frame that predicts a protein of 442 amino acids. Based on its deduced amino acid sequence, the protein contains hydrophobic amino acid domains at its N- and C-terminus that are characteristic of signal peptide and GPI-anchor addition sites, respectively. The most striking feature of the predicted protein, however, is a series of tandem repeats that spans most of its length. The repeats themselves are characterized by periodic cysteine residues that fall into register when the homologous segments are aligned. interestingly, the spacing of cysteines (C-X-2,X-3-C) within a framework of larger (C-X-2-C-X-20-C-X3C-X-20-C-X2C) motifs is entirely consistent with the structure of known zinc-binding proteins. Finally, comparison of the coding sequence of the 48 kDa i-antigen gene with a partial cDNA previously thought to encode this protein reveals nearly complete identity except at their 3' ends, suggesting that alternative forms of the antigen exist. (C) 1999 Elsevier Science B.V. All rights reserved.