Fig. 3: SERS spectra of protein and oligomer.

a Represents the SOD1 (PDB ID: IHL5100) positive charge residues responsible for the electrostatic attractions with the silver nanoparticle and surface charge (blue for positive, red for negative) give an idea about possible attachment orientation of SOD1 protein, (R = Arginine, K = Lysine, H = Histidine) b give idea about possible attachment orientation of oligomer with the silver nanoparticle, c SERS spectra of protein (black), oligomer (red) and oligomer formed in presence of quercetin (blue)65,85,90,91,101,102.