An investigation into the self-assembly of aromatic amino acids: structural polymorphism, unusual stability, and detection of the metastable intermediates

Abstract

Biomolecular self-assembly is a ubiquitous process in nature. Among all the biomolecules, the self-assembly of proteins and peptides has attracted immense interest due to their ability to form various nanostructures with important cellular organizations and functions [1,2]. However, their uncontrolled aggregation can lead to the formation of amyloid fibrillar structures, which are associated with several diseases like Alzheimer’s disease, type II diabetes, Parkinson’s disease, and many more [3,4]. Several attempts were made to understand the fundamental principles that govern the self-assembly process, but the mechanism of structural transitions of the proteins and peptides remains elusive. In this context, a reductionist approach can be targeted at understanding the self-assembly of the amino acids, as they serve as the simplest building blocks of proteins or peptides. Recently, amyloid-like fibrillar structures with cytotoxic effects have been reported for single amino acids like phenylalanine, tryptophan, and tyrosine [5,6]. This thesis summarizes the experimental results of the self-assembly process of aromatic amino acids and the effect of several external stimuli, like metal ions, pH, temperature, etc., on the self-assembly process using several spectroscopic and microscopic techniques. The thesis also provides a detailed study of how the emission properties of carbon dots can be exploited for the visual detection of different intermediates during self-assembly formation by amino acids.