Ribosome inactivating proteins (RIPs) depurinate ribosomal RNA (rRNA) disrupting the synthesis of proteins. This causes cell death imparting the toxicity that RIPs possess. One very specific RIP of interest is ricin; used as a biological weapon, it can have a direct impact on agriculture, the economy, and human life. Owing to the devastating impact that ricin can have, its function, structure, and biochemical nature are of interest to many different scientific disciplines such as biochemistry, medicine, and the forensic science community. However, ricin is a hazardous protein to work with because it affects eukaryotic rRNA. Pokeweed antiviral protein (PAP), on the other hand, behaves very similarly to ricin but cannot directly access the eukaryotic cell as ricin can, making it safer for study while serving as an important model. PAP is a single-chain RIP purified from the leaves of Phytolacca Americana and has been found to depurinate the conserved �-sarcin/ricin loop of the large ribosomal subunit in plant viruses. It has also been found that PAP depurinates uncapped mRNA indicating a specific site on the mRNA that PAP can bind to and possibly use as a mechanism to interfere with protein synthesis. Certain structural elements of uncapped mRNA may be of key interest in elucidating this process. We use Tobacco Etch Virus (TEV) mRNA as a model for these studies. Differing constructs of the mRNA containing specific pseudoknots, stems, and loops of the non-translating region in the TEV uncapped mRNA are analyzed for their effects on equilibrium binding with PAP.