Self‐assembly of a peptide sequence, EKKE, composed of exclusively charged amino acids: Role of charge in morphology and lead binding

The self‐assembly of peptides is influenced by their amino acid sequence and other factors including pH, charge, temperature, and solvent. Herein, we explore whether a four‐residue sequence, EKKE, consisting of exclusively charged amino acids shows the propensity to form self‐assembled ordered nanostructures and whether the overall charge plays any role in morphological and functional properties. From a combination of experimental data provided by Thioflavin T fluorescence, Congo red absorbance, circular dichroism spectroscopy, dynamic light scattering, field emission‐scanning electron microscopy, atomic force microscopy, and confocal microscopy, it is clear that the all‐polar peptide and charged EKKE sequence shows a pH‐dependent tendency to form amyloid‐like structures, and the self‐assembled entities under acidic, basic and neutral conditions exhibit morphological variation. Additionally, the ability of the self‐assembled amyloid nanostructures to bind to the toxic metal, lead (Pb2+), was demonstrated from the analysis of the ultraviolet absorbance and X‐ray photoelectron spectroscopy data. The modulation at the sequence level for the amyloid‐forming EKKE scaffold can further extend its potential role not only in the remediation of other toxic metals but also towards biomedical applications. The four‐residue sequence, EKKE, consisting of exclusively charged amino acids shows a pH‐dependent tendency to form amyloid‐like structures, exhibiting morphological variation. The self‐assembled amyloid nanostructures bind to the toxic metal, lead (Pb2+). Modulation of the EKKE scaffold could extend its potential role in the remediation of other toxic metals and towards biomedical applications.