Construction of a recombinant expression plasmid encoding a staphylococcal protein A-ricin A fusion protein.

A recombinant plasmid has been constructed containing the coding regions for a functional fragment of staphylococcal protein A and the entire ricin A chain in tandem in the same reading frame. The recombinant gene has been expressed in Escherichia coli cells to produce a protein with both staphylococcal protein A activity and ricin A chain activity. Such a fusion protein could be used for producing immunotoxins.