I recently completed independent research projects under the supervision of Dr. Ogg in biotechnology of medicinal plants. one is about a novel fusion antiviral protein composed of two very potent ribosome inactivating proteins. You can read the abstract here below, and can access the full article at the end of the page.
Pokeweed antiviral protein (PAP) is a single-chain ribosome-inactivating protein that exists in several forms isolated from various organs and at different stages of development of Phytolacca americana (pokeweed). In this study, PAP-S1, one of the two known isoforms found in seeds, was isolated and PCR amplified using primers based on the known mRNA of PAP-S2, the other known form found in seeds. The complete cDNA encoding PAP-S1 was determined here for the first time. PAP-S1 is a potent antiviral protein with many potential clinical applications. However, it was found to be dosage dependent with observed side effects at high dosage. In this study, we report the production of a recombinant antiviral peptide-fusion protein between Ricin A-chain and PAP-S1. The peptide-fusion recombinant proteins Ricin-A-Chain/PAP-S1 and PAP-S1/Ricin-A-Chain were generated by joining the N-terminus of PAP-S1 to the C-terminus of Ricin A-chain and the C-terminus of PAP-S1 to the N-terminus of Ricin A-chain respectively, and were expressed in an Escherichia coli cell free expression systems. The peptide-fusion recombinant protein Ricin-A-Chain/PAP-S1 (F2) was found to be more active than the PAP-S1/Ricin-A-chain (F1) and similar to PAP-S1 in a cell free prokaryotic environment (in this order of activity PAP-S1>F2>F1), and both showed much stronger activity in a cell free eukaryotic environment. The DNA sequence of the complete cDNA of PAP-S1 and of the peptide-fusion protein Ricin-A-Chain/PAP-S1 with the PAP-S1 signal peptide at the N-terminus of Ricin A-chain were inserted in plant destination binary vectors for A. tumefaciens mediated transformation. It is the authors’ opinion that additional research should be done in order to determine both cytotoxicity and selectivity of fusion protein F2 compared to PAP-S1, as it could be a viable, more potent and less cytotoxic alternative to PAP-S1 alone at high dosage, for both agricultural and therapeutic applications.
Keywords: N-glycosidase, Phytolacca americana, pokeweed antiviral protein, Pokeweed antiviral protein from seeds, ribosome-inactivating protein, cDNA, Fusion protein, Inhibition of in vitro protein synthesis
You can read the full research article here: Research Project Fusion-V3L