Characterization of Self-assembled Phenylalanine High Ordered Aggregates

Gabriel Alexander Kupovics, Zeina Ismael Alraawi, and Thallapuranam Krishnaswamy Suresh Kumar, Department of Chemistry and Biochemistry, University of Arkansas, 119 Chemistry Building, 1 University of Arkansas, Fayetteville, AR 72701

Excessive concentrations of the natural aromatic amino acid, phenylalanine, is characteristic of the severe genetic abnormality known as phenylketonuria (PKU). Patients with the disease experience seizures, behavioral disorders, developmental delay, and permanent cognitive impairment. It has been demonstrated that phenylalanine self-assembles into fibrillar, amyloid-like deposits (Adler-Abramovich et al., 2012) in a pattern that resembles a beta-sheet secondary structure (Mossou et al., 2015). Additionally, intermolecular π-π stacking, hydrogen-bonding, and electrostatic interactions have been proposed as mechanisms of phenylalanine self-assembly (Do et al., 2015 and Tomar et al., 2019). This research aims to supplement previous findings on the phenylalanine self-assembly process via alternative experimentation methodologies. Transmission electron microscopy (TEM) data of phenylalanine reveals the formation of higher ordered fibrillar structures by the amino acid in vitro. Further, solution buffer salts are depicted coating the micrograph fibrils, indicating the presence of cation-π interactions and suggesting the plausible requirement of π-π interactions for phenylalanine aggregation. Thioflavin T extrinsic fluorescence kinetics in the presence of sodium dodecyl sulfate (SDS), an amphipathic detergent, reveals a higher propensity of phenylalanine to aggregate in the presence of SDS, and a tendency to form highly branched fibrillar assemblies under membrane-like conditions. Extrinsic fluorescence kinetics of phenylalanine at varying pH reveal a higher propensity to self-assemble at pH 2. This research confirms that phenylalanine can form supramolecular structures in vitro and further suggests that π-π stacking and hydrophobic interactions play an important role in these self-assembly processes. These data will be discussed in detail. 

Additional Abstract Information

Presenter: Gabriel Kupovics

Institution: University of Arkansas

Type: Poster

Subject: Biochemistry

Status: Approved

Time and Location

Session: Poster 1
Date/Time: Mon 1:30pm-2:30pm
Session Number: 2150