Materials Research Science and Engineering Center

Adrianna Shy

"Reconstruction of beta-sheet peptides and an analysis of their self-assembling abilities"

Adrianna Shy*, Jie Li, Bing Xu

Abstract

The chemical interactions in a protein is key to understanding its secondary structure. Hydrogen interactions between amino acids in adjacent chains form beta-pleated sheets. 1-pyrenebutyric acid promotes the self-assembly of these small molecules. In this study, focus is placed on the interactions between small peptide chains isolated from the hormone, irisin. We hypothesize that the morphology of a peptide mixture will yield more interactions than a single peptide alone. We also explored recreating the β-sheet structure displayed by irisin. Solid-Phase Peptide Synthesis was used to synthesize the peptides: IQEVN and RMLRF alone, as well as RMLRF, IQEVN and VIGFA with 1-pyrenebutyric acid (Py) attached. Hydrogels were formed, and various techniques such as NMR, TEM, and circular dichroism were used to confirm self-assembly and analyze their β-sheet structure. Results reveal that Py-IQEVN and Py-RMLRF self-assemble on their own. A mixture of these two also show that a β-sheet-like structure was created. The hydrophobicity of Py-VIGFA does not allow hydrogelation, therefore it was not analyzed. However, MTT assays show Py-VIGFA along with Py-RMLRF and Py-IQEVN are toxic to cancer cells at high concentrations. Overall, more interactions happen between RMLRF and IQEVN when 1-pyrenebutyric acid is attached, while single peptides without this molecule show no type of self-assembly. In the future, the morphology of D-peptide molecules will be explored to mimic the L-peptide interactions.

Support: MRSEC REU