Examining the interaction and inhibition of lysozyme fibrillation by chelerythrine through multispectroscopic and imaging studies

Aggregation of proteins leads to amyloid fibrillogenesis which is related to various neurodegenerative dysfunctions. In the present work, interaction and impact of benzophenanthridine alkaloid chelerytherine (CHE) on fibrillogenesis of chicken egg white lysozyme (LYS) was examined employing various biophysical techniques. The intrinsic fluorescence of LYS was quenched upon addition of CHE. The mechanism of quenching was static in nature. From the FRET theory, we evaluated the distance between LYS and CHE and it was found to be 3.42 nm. Molecular docking analysis revealed the involvement of hydrogen bonding and hydrophobic interactions in the complexation process. The microenvironmental alteration around the protein residues upon binding with CHE was obtained from 3D-fluorescence and synchronous fluorescence spectroscopic analysis. The impact of CHE on amyloid fibrillation of LYS was studied using Thioflavin T fluorescence, congo red absorbance, FTIR analysis and AFM imaging studies. These results clearly revealed that the amyloid fibrillation of LYS was effectively inhibited by CHE. Nile red and 8-Anilino-1-napthalenesulphonic acid assays supported that CHE arrested the LYS fibrillation. In summary, our study reveals the antiamylodogenic potential of CHE which can be extremely useful for the development of new anti-amyloid therapeutics.