Abstract:

To construct an expression plasmid and express Staphylococcus aureus Protein A(SPA) in a prokaryotic expression system. The initially study concerned the affinity of purified SPA with IgGs from different sorts of animals. MethodsPCR was used to amplify the target gene with the genome of Staphylococcus aureus as a template. The recombination plasmid pET30a(+)SPA was constructed and transformed into E.coli BL21 competent cells. The recombinant protein was expressed with induction of IPTG and identified by SDSPAGE and Westernblot followed by purification with His·Bind Protein Purification Kit. After that ELISA was used to study the affinity of purified SPA with different IgGs from humans, rabbits, mice, swine and goats. ResultsThe expression plasmid pET30a(+)SPA was constructed successfully and the objective protein was expressed. The recombination protein showed high affinity with IgGs from humans and mice but low affinity with IgGs from rabbits and swine. ConclusionThe recombination protein has high affinity with IgGs from humans and mice but low affinity with IgGs from rabbits and swine, and so lays a foundation for SPAELISA.

Key words: Staphylococal Protein A； Prokaryotic expression； Affinity