Self-assembly of a peptide sequence,EKKE, composed of exclusively charged amino acids: Role of charge in morphology and lead binding |
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Authors: | Aishwarya Natarajan Krishnan Rangan Ramakrishna Vadrevu |
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Institution: | 1. Department of Biological Sciences, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, India;2. Department of Chemistry, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, India |
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Abstract: | 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. |
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Keywords: | amyloid peptide scanning electron microscopy self-assembly ThT fluorescence X-ray photoelectron spectroscopy |
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