Expression of Pokeweed Antiviral Protein Isoform S1 (PAP-S1) and of Ricin-A-Chain/PAP-S1 Novel Fusion Protein (RTA/PAP-S1) in <em>Escherichia coli </em>and Their Comparative Inhibition of Protein Synthesis <em>in Vitro</em>

Abstract

Fusion protein therapeutics engineering is advancing to meet the need for novel medicine. Herein, we further characterize the development of novel RTA & PAP-S1 antiviral fusion proteins. In brief, RTA/PAP-S1 and PAP-S1/RTA fusion proteins were produced in both cell free and E. coli in vivo expression systems, purified by His-tag affinity chromatography, and protein synthesis inhibitory activity assayed by comparison to the production of a control protein, CalmL3. Results showed that the RTA/PAP-S1 fusion protein is amenable to standardized production and purification and has both increased potency and less toxicity compared to either RTA or PAP-S1 alone. Thus, this research highlights the developmental potential of novel fusion proteins with reduced cytotoxic risk and increased potency.