2型猪链球菌强毒株与非致病株胞外蛋白的比较蛋白质组初步研究

Comparative proteome study on extracellular proteins of virulent and avirulent Streptococcus suis type 2

为建立2型猪链球菌(S.suis2)胞外蛋白组双向电泳样品的制备方法,本研究利用双向电泳(2-DE)分离S.suis2强毒株与无致病株的胞外蛋白,分别得到它们的胞外蛋白图谱。在pH4～pH7范围内采用考马斯亮蓝R350染色法在2菌株的胞外蛋白质图谱中都分别检测出180±10个蛋白点,并且它们的蛋白质分子质量分布基本相似;在所检测到差异蛋白点中,其中有50个蛋白点只存在于无致病菌株中而强毒株中不存在,有52个蛋白点只存在于强毒株中而无致病菌株中不存在,有7个蛋白点在2菌株中的表达量相差5倍以上。我们在强毒株凝胶中挑取了10个差异蛋白点进行质谱分析,通过数据库检索,鉴定了其中的9个蛋白,另外1种与鞭毛蛋白有同源序列。这些结果为研究S.suis2的致病机理提供了蛋白质组学方面的信息。

The extracellular proteins of Streptococcus suis type 2 virulent strain and avirulent strain was separated by two-dimensional electrophoresis （2-DE） and the 2-DE profiles were compared. The results showed that both strains have 180 ±10 protein spots with similar molecular masses. Howevers there were about 50 protein spots in avirulent strain not displayed in the virulent strain, and 52 protein spots in virulent strain not displayed in avirulent strain. There were 7 spots showed more than 5 folds expression changes between the two strains. Ten mis-matched spots in the 2-DE map of S. suis type 2 virulent strain were cut out and 9 proteins were successfully identified by MALDI-TOF-MS and/or MALDI-TOF/TOF-MS. One protein showed homologous sequence with flagellin. These proteomie results would provide insight into further understanding of pathogenic mechanism of S. suis type 2.