摘要
通过PCR方法扩增Ⅰa型牛源无乳链球菌地方菌株M7的Sip基因,将目的片段克隆入pGEM-T Easy载体并进行测序,采用多种生物软件对Sip基因及其表达的蛋白质进行分子特征分析。试验结果表明,M7菌株的Sip基因为1305bp,未出现基因缺失;与GenBank中发表的不同血清型的无乳链球菌菌株的相应核苷酸序列同源性为98.0%～100.0%,推导的氨基酸同源性为97.2%～99.8%。M7的Sip基因与中国菌株Ly2(FJ808732)和美国菌株GB00549(FJ752159)的相应基因的核苷酸同源性和氨基酸同源性最高,核苷酸同源性均为100.0%,氨基酸同源性均为99.8%。该Sip基因表达的蛋白质是一种稳定的分泌性外膜蛋白,疏水性强;其N-末端的第52-95位氨基酸残基之间含有1个LysM超家族的保守结构域;存在1-25位氨基酸的信号肽,剪切位点在第25-26位氨基酸之间;存在多个B细胞和T细胞表位。说明M7菌株的Sip基因是未缺失LysM超家族结构域的比较保守的免疫蛋白。
The Sip gene of the isolate M7 of Ⅰa serotype Streptococcus agalactiae from bovine was amplified using the PCR method,cloned into pGEM-T Easy vector and then sequenced.The molecular characteristics of Sip gene and its expression protein were analyzed using a variety of biological software.The results showed that Sip gene of M7 was 1305 bp and did not appear the gene deletion,the Sip gene of nucleotide sequence derived from M7 had a 98.0% to 100.0% of homology and a 97.2% to 99.8% amino acid homology among the corresponding sequences published in GenBank.Furthermore,the Sip gene of M7 shared of 100.0% nucleotide homology and 99.8% of amino acid identity with that of Ly2（FJ808732）strains in China and GB00549（FJ752159）in USA,respectively.The expression protein of Sip gene was a stable outer membrane protein,which was secretion protein and hydrophobic highly.The polypeptide contained a LysM functional domain which was related to immunoregulation between the N-terminal 52nd to 95th amino acid residues and a signal peptide consisting of 25 amino acids,which of cleavage site between 25th and 26th amino acids.Moreover there were a number of B cell and T cell epitopes on the protein.The results illustrated the Sip protein of M7 strain was conservative immune proteins without missing LysM superfamily domain.
出处
《中国畜牧兽医》
CAS
北大核心
2012年第11期7-12,共6页
China Animal Husbandry & Veterinary Medicine
基金
国家奶牛产业技术体系科学家岗位项目(CARS37)
国家科技支撑项目“奶牛健康养殖重要疾病防控关键技术研究”(2012BAD12B03)
关键词
牛
无乳链球菌
Sip基因
Ⅰa型
bovine
Streptococcus agalactiae
surface immunogenic protein（Sip） gene
Ⅰa serotype
