嗜麦芽寡养单胞菌D2株2套Ⅱ型分泌系统的全基因簇序列测定及分析

Omni-Gene Clusters Sequencing and Analyzing of Two Sets of Type ⅡSecretion System in Stenotrophomonas maltophilia D2 Strain

嗜麦芽寡养单胞菌D2株经前期研究发现有2套Ⅱ型分泌系统（T2SS），根据嗜麦芽寡养单胞菌K279a、R551—3、JV3、D457的T2SS基因簇序列，以及D2株的部分测序结果设计引物，采用基因移步法逐一扩增2套T2SS基因序列，产物连接至T载体，经酶切鉴定后测序、拼接。发现有22个完整的开放多码框架（ORF），比对分析后发现T2SSl的基因簇与同种属细菌相应基因簇序列同源性均在80％以上，对应氨基酸序列同源性均能达到97％以上，而T2SS2基因簇与K279a、R551—3对应基因序列和氨基酸序列的同源性均不及T2SS1高。2套T2SS的GspE、F、I基因同源性在50％以上，其他对应基因同源性在35％～68％之间不等，氨基酸序列同源性则为15％～61％。2套他ss与铜绿假单胞菌PA01的同源性高于不同科的小肠结肠炎耶尔森菌。T2SS的序列测定及同源性分析为进一步研究细菌蛋白分泌机制奠定基础。

Two sets of type II secretion system （T2SS） were found through early study on Stenotrophomoruts maltophilia D2 strain. Primers were designed according to the T2SS sequences of S. maltophilia D2＇s K279a, 11551-3, JV3, D457 gene clusters, and parts of sequencing results of D2 strain, adopting gene walking method to amplify two sets of T2SS gene sequence one by one, the products were linked to T vector, and determined the sequence and spliced after enzyme digestion identification. It was found that there were 22 complete ORFs, and it was found after comparative analysis that the gene clusters of T2SS had above 80% of homology the corresponding gene clusters of bacterium of the same species and genus, and the homology of corresponding amino acid sequence could reach over 97% , while the homology of corresponding gene sequence and amino acid sequence between T2SS gene clusters and K279a, R551-3 was not as high as T2SS1. GspE, F, I, gene homology of two sets of T2SS were over 50%. And homolgy of other corresponding genes was differed between 35% -68% , the homology of amino acid sequence was between 15% -60%. The homology of two sets of T2SS with Pseudomonas aeruginosa PAO1 was higher than Yersinia enterocolitica of different family. Sequencing of T2SS and homologous analysis had laid a foundation for further study on the bacterial protein excretion mechanism.