中国寄生虫学与寄生虫病杂志 ›› 2013, Vol. 31 ›› Issue (1): 7-33-38.

• 论著 • 上一篇    下一篇

恶性疟原虫红细胞表面膜蛋白1 DBLα区 不同区域与肝素的结合特性分析

张岩1,孙喜东2,杨春3,张雅那1,宋盟1,陆慧君1,姜宁1,尹继刚1 *,陈启军1   

  1. 1 人兽共患病研究教育部重点实验室,吉林大学人兽共患病研究所,长春130062;2 解放军第208医院血站,长春130062;3 中国农业科学院特产研究所,长春130112
  • 出版日期:2013-02-28 发布日期:2013-04-23

The Binding Property of Different Regions in Duffy-binding-like Domain α of Plasmodium falciparum Erythrocyte Membrane Protein 1 to Heparin

ZHANG Yan1,SUN Xi-dong2,YANG Chun3,ZHANG Ya-na1, SONG Meng1,LU Hui-jun1,JIANG Ning1,YIN Ji-gang1 *,CHEN Qi-jun1   

  1. 1 Key Laboratory of Zoonosis,Ministry of Education;Institute of Zoonosis,Jilin University,Changchun 130062,China;2 Blood Bank,PLA 208 Hospital,Changchun 130062,China;3 Institute of Special Economic Animal and Plant Science,Chinese Academy of Agricultural Sciences,Changchun 130112,China
  • Online:2013-02-28 Published:2013-04-23

摘要: 目的  克隆、表达恶性疟原虫红细胞表面膜蛋白1 DBLα(PfEMP1-DBLα)及其3个分段区域编码基因,筛选出PfEMP1-DBLα区与红细胞表面受体-肝素/硫化肝素亲和力最强的序列。  方法  根据大肠埃希菌密码子组成特点,重新优化并合成恶性疟原虫FCR3S1.2株PfEMP1-DBLα1245基因序列,采用PCR方法,将优化后的基因序列分DBLαA、DBLαB和DBLαC等3段扩增。分别将全长基因和3个片段基因亚克隆至PGEX?鄄4T?鄄1载体,转化至大肠埃希菌BL21(DE3),异丙基-β-D-硫代半乳糖苷(IPTG)进行诱导表达。用谷胱甘肽?鄄S?鄄转移酶标签亲和层析法纯化表达产物。通过重组蛋白与肝素的亲和试验及糖胺聚糖(GAG)抑制试验,分析功能区与肝素的亲和力情况。  结果  含重组质粒的4个表达菌株(BL21?鄄GEX-DBLα1245、BL21-GEX-DBLαA、BL21-GEX-DBLαB和BL21GEX-DBLαC)经IPTG诱导,获得以可溶形式存在的重组蛋白,相对分子质量(Mr 73 600、Mr 41 600、Mr 42 500和Mr 41 500) 与预测的融合蛋白大小相符。重组蛋白与肝素的亲和试验及GAG抑制试验结果表明,在PfEMP1-DBLα分段表达的3个功能区中,DBLα1245、DBLαA(1~142 aa)、DBLαB(143~284 aa)和DBLαC(285~415 aa)等4个重组蛋白均可与肝素结合,阴性对照GST不与肝素结合,其中DBLαC对肝素的亲和力最强。  结论  PfEMP1-DBLα区与肝素/硫化肝素亲和力最强的序列为Q285~Y415(即DBLαC),该段序列在恶性疟原虫感染的红细胞与周围红细胞的黏附过程中起关键作用。

关键词:  恶性疟原虫, 膜蛋白, 肝素

Abstract: Objective  To clone and express Plasmodium falciparum erythrocyte membrane protein 1 DBLα (PfEMP1-DBLα) and three fragments genes, and screen the strongest affinity sequence with the red blood cell surface receptors?鄄heparin or heparin sulfate in the structure of PfEMP1-DBLα.  Methods  The sequence of PfEMP1-DBLα1245 was optimized according to the characteristics of E. coli codon, synthesized, and divided into three fragments (DBLαA, DBLαB, and DBLαC) by PCR. Full-length gene and three gene fragments were subcloned into PGEX-4T-1 vector, and transformed into E. coli BL21 and then induced with IPTG for expression. The recombinant protein was purified from bacterial lysates using gluthathione-Sepharose 4B. Heparin affinity test and glycosaminoglycan (GAG) inhibition test were used to analyze the affinity between recombinant protein and heparin.  Results  Four recombinant proteins(DBLα1245, DBLαA, DBLαB, and DBLαC) were expressed as solubility and the relative molecular weight (Mr 73 600, Mr 41 600, Mr 42 500, and Mr 41 500) were conformed to the prediction size. Heparin affinity test and GAG inhibition test showed that the four recombinant proteins were binded to the heparin-Sepharose, but not for the GST control. DBLαC (Q285-Y415) had the strongest affinity to heparin.  Conclusion  The strongest affinity sequence with heparin or heparin sulfate in the structure of PfEMP1?鄄DBLα is Q285-Y415, which plays a role in binding of Plasmodium falciparum infected red blood cells to the peripheral red blood cells.

Key words: Plasmodium falciparum, Membrane protein, Heparin