Prokaryotic expression and purification of the recombinant methyl-accepting chemotaxis protein gene 05SSU0273from Streptococcus suisserotype 2

To study the biological function of the methyl-accepting chemotaxis protein(MCP) gene 05SSU0273 and its products in Streptococcus suis serotype 2,a pair of specific primers was designed for the gene 05SSU0273,and the target DNA fragment was successfully amplified using the genomic template of Chinese strains 05ZYH33.Subsequently,target gene was inserted into pMD18-T vector,and then subcloned into prokaryotic expression vector pET32a,generating a recombinant expression plasmid pET32a: 05SSU0273.Direct DNA sequencing method was used to confirm its correctness.The recombinant plasmid was then transformed into E.coli BL21.After IPTG induction,this bacteria could produce the target MCP protein with 6×his-tag which could be purified by affinity chromatography system.The results of SDS-PAGE and Western-blot showed that the fusion protein had a relative molecular weight of 43 kD.Moreover,MCP gene had been detected in 20 of 35 S.suis strains with different serotypes.This prevalence indicated that protein MCP might play a role in the survival of S.suis 2 in different hosts.Together,our work laid foundation for functional research on MCP in S.suis 2.