ABSTRACT
This chapter describes an Escherichia coli system which secretes α-Sarcin into the periplasmic space efficiently, and a convenient procedure for the purification of the protein. The inhibitory effect of both secreted and authentic α-Sarcin was assessed on in vitro protein synthesis from rabbit reticulocyte lysates. The recombinant α-Sarcin inhibited protein synthesis in a similar manner with that of authentic α-Sarcin. The recombinant protein was twice as active as authentic α-Sarcin on the inhibition of protein synthesis. A preliminary immunostaining experiment revealed that the increase of the band intensity could be due to an expression of recombinant α-Sarcin. The authors develop an efficient system for the expression of α-Sarcin in E. coli using cDNA encoding α-Sarcin and the expression vector pKTN2-2. The resulting construct in the expression plasmid loses three nucleotides (GCG) between the bla signal sequence and the sequence for α-Sarcin that encodes alanine of authentic α-Sarcin.
