Infectious diseases have been a growing health care concern resulting in added expenses and health care resources to the community. Due to this rising issues research groups have devoted time to resolve this growing issue through the development of various compounds to treat or prevent disease. Research at the University of New Mexico began with trying to kill various strains of bacteria with a novel class of synthetic phenylene ethynylene (PPE)-based conjugated polyelectrolytes (CPEs) has helped in providing a new antimicrobial compound. Results proved successful and lead to experimentation to use the new class of compounds as an antiviral answer as well. The compounds showed high level of inactivation for two model viruses MS2 and T4 bacteriophages. The compound also showed morphological changes to the viral capsids composed of protein assemblies. Due to the results of previous research the mechanism by which the composed interacted with the protein remained unanswered. Studies were conducted using two model proteins BSA and lysozyme, oppositely charge working in buffers at pH 7.4, to establish a mean by which the compounds affect the proteins. Various spectroscopic techniques were utilized to understand how the proteins are affected on a molecular level. CD was used to examine changes to the secondary structure of the proteins, fluorescence to examine tertiary structural changes. SDS-PAGE and SEC-HPLC with static light scattering to examine the products of the interaction aggregates or small products then determine the molecular mass of these results. The CD results showed that BSA was more prone to secondary structural changes. Initial suspected to be caused by the electrostatic interaction between the negative charged BSA and the cationic compounds tested. However, fluorescence results showed similar trends for both BSA and lysozyme leading to more than electrostatics affecting the interaction as the fluorescence results provide information on the tertiary structure for the proteins. Next two separation techniques were utilized to look at how the protein could be chemical altered through cleavage or aggregation. SDS-PAGE provided the first set of results qualitatively showing the compounds cause both aggregation and cleavage in the presence of BSA while lysozyme only showed aggregation. To gather a quantitative result for how this occurred SES-HPLC with static light scattering was used. The results gathered showed that BSA underwent more of an aggregation process with irradiating causing some cleavage of the protein. Lysozyme on the other hand resulted in more cleavage products than aggregates only see effect after irradiation. When gathering all the information it is suspected that the main form for interaction begins with hydrophobic interactions with the compounds trying to keep the back bones away from the solvent environment which would explain why more hydrophobic BSA resulted in more structural change without irradiation.
Level of Degree
NIH 189789-1 NSF 1207362
Soliz, Gregory. "Cationic Phenylene Ethynylene Polymers and Oligomers Induce Conformational Changes to Proteins." (2015). https://digitalrepository.unm.edu/bme_etds/5