《环境昆虫学报》

肽聚糖识别蛋白（peptidoglycan recognition protein, PGRP）对于昆虫来说是一种高度保守的病原识别蛋白。为阐明PGRP-S2在小菜蛾Plutella xylostella抵抗病原微生物过程中的作用，本研究结合RT PCR和RACE技术克隆得到小菜蛾PGRP-S2基因的cDNA全长序列，命名为PGRP-S2（GenBank登录号：MG570190）。生物信息学分析结果表明，PGRP-S2的开放阅读框为588 bp，编码195个氨基酸；蛋白质预测分子量为21 46 kDa，理论等电点为8 46；编码蛋白具有PGRP超家族保守结构域和酰胺酶结构域，是典型的肽聚糖识别蛋白，包含一条信号肽，不存在跨膜结构；同源序列比对和系统进化树分析表明 PGRP-S2与家蚕Bombyx mori的BmPGRP S1进化距离最近。利用大肠杆菌 Escherichia coli BL21（DE3）高效表达重组蛋白PxPGRP-S2，利用倒置显微镜及平板涂布观察重组蛋白对大肠杆菌E. coli和金黄色葡萄球菌Staphylococcus aureus的作用，结果表明PxPGRP-S2蛋白能够与两种细菌发生结合并凝集细菌，但不具备直接杀菌功能。本研究为进一步研究基于PGRP-S2介导的小菜蛾免疫防御反应提供基础。

英文摘要:

Peptidoglycan recognition protein（PGRP） is a highly conserved pathogen recognition protein for insects. In order to elucidate the role of PGRP-S2 in the resistance of P. xylostlla to pathogenic microorganisms, the full length cDNA of PGRP-S2 gene of P. xylostlla was obtained by RT PCR and RACE, and named as PGRP-S2 (GenBank accession：MG570190). According to bioinformatics analysis, with an open reading frame of 588 bp, PGR-S2 encodes 195 amino acids, the predicted molecular weight of the protein is about 21.46 kDa, and the theoretical isoelectric point is 8.46. The encoded protein has a conserved domain of PGRP superfamily and amidase domain, which are typical of peptidoglycan recognition proteins, and contains a signal peptide without transmembrane structure; homologous sequence alignment and phylogenetic tree analysis showed that PGRP-S2 was closest to BmPGRP-S1 of Bombyx mori. The recombinant protein PxPGRP-S2 was highly expressed in Escherichia coli BL21（DE3). The interaction between the recombinant protein PxPGRP-S2 with E. coli and Staphylococcus aureus was observed by an inverted microscope and plate coating. The results showed that PxPGRP-S2 protein could be bind to both bacteria and agglutinate bacteria, but not could kill them directly. The study would lay a foundation for the prevention and further study for the PGRP-S2 mediated immune defense responses in P. xylostella.

查看全文查看/发表评论下载PDF阅读器

关闭