论文部分内容阅读
目的 :对比分析编码 90 k Da的表面变异蛋白 ( VSP)基因与已发表的其它 VSP基因。方法 :应用聚合酶链反应 ( PCR)技术、PCR产物的克隆技术和插入基因片段的序列测定。结果 :从贾第虫 0 2 - 4 A1基因组中将编码 90 k Da的表面变异蛋白几乎全长的基因调出 ,经序列分析 ,此基因长度为 2 0 19bp,编码 654个氨基酸 ,具有一个开放阅读框架。推导出的氨基酸序列的半脱氨酸含量丰富 ( 11.8mol% ) ,而且多数的半脱氨酸以 CXXC基序重复出现 2 6次。苏氨酸含量为 11.3mol% ,甘氨酸为 10 .9mol% ,丙氨酸为 10 .1mol%。序列分析发现有 2个天冬酰氨连接的糖基位点。结论 :象其他 VSPs一样 ,CRISP90具有一个高度保守疏水性 C末端。经同源性比较发现 ,与 CRP72有 56%的同源性。这一结果对研究贾第虫株的表面变异抗原基因的表达具有一定的意义。
OBJECTIVE: To compare and analyze the 90 kDa surface variant protein (VSP) gene with other published VSP genes. Methods: Polymerase chain reaction (PCR) technology, cloning technology of PCR products and sequence analysis of inserted gene fragments were used. Results: The gene encoding almost 90 kDa surface variant protein was transferred from the 0 2 - 4 A1 genome of Giardia and sequenced. The gene was 2019 bp in length and encoded 654 amino acids with an open Reading frame. The deduced amino acid sequence is rich in hemi-desaturase (11.8 mol%), and most of the half-amino acids are repeated 26 times with the CXXC motif. The threonine content is 11.3 mol%, the glycine is 10.9 mol%, and the alanine is 10.1 mol%. Sequence analysis revealed two asparagine linked glycosyl sites. Conclusions: Like other VSPs, CRISP90 has a highly conserved hydrophobic C-terminus. Homology comparison showed that there was 56% homology with CRP72. This result is of certain significance for the study of the expression of surface variant antigen genes in Giardia strains.