猪链球菌2型核糖核酸酶Ⅲ的克隆表达及催化特性分析OACSTPCD

In order to identify the catalytic properties of RNase Ⅲ Streptococcus suis serotype 2 RNase Ⅲ(SS-RNase Ⅲ),we used Esche-richia coli BL21(DE3)to heterologously express RNase Ⅲ of Streptococcus suis serotype 2,and the bacterial RNase Ⅲ was then isolated and purified by nickel column affinity chromatography.Next,various catalytic properties of SS-RNase Ⅲ were analyzed.The results were that heterologous expression showed most of the recombinant protein RNase Ⅲ to be soluble,that the catalytic properties showed RNase Ⅲ mainly relying on Mg2+or Mn2+to perform catalytic functions with different catalytic activities under different ion concentrations and pH environments,that substrate specific analysis showed RNase Ⅲ to specifically cleave double stranded RNA with a length of 30bp,with good specificity for endogenous rnc mRNA and 5S rRNA.The above results indicated that SS-RNase Ⅲ had unique catalytic properties,which provided theoreti-cal basis for a deeper understanding of how SS-RNase Ⅲ mediates the pathogenesis of Streptococcus suis serotype 2.