Histidine-tagged Barley Stripe Mosaic Virus (BSMV-His) virus-like particles (VLPs), which display histidine residues on their surface, provide a robust platform for the biotemplated synthesis of palladium nanorods (PdNRs). To enhance metal-binding capability, computational analysis was conducted to identify active site residues potentially involved in virus–metal interactions. From these, LEU98, LYS100, ILE103, LEU106, and THR107 were selected for substitution with histidine. Thermodynamic parameters (ΔG), Z-scores, and Ramachandran plot analysis indicated that substitutions such as K100H did not induce unfavorable conformations and maintained overall protein stability. Additionally, normal mode analysis revealed that histidine-tagged structures exhibited lower eigenvalues compared to the wild-type protein, suggesting increased structural flexibility. The incorporation of six histidine residues at the surface-exposed C-terminus of BSMV capsid proteins was compatible with proper folding and VLP assembly, as confirmed by transmission electron microscopy (TEM). Thick Pd mineralization layers were achieved after only two coating cycles. The effect of different Pd precursor solutions on mineralization thickness was evaluated, alongside kinetic studies of Pd ion adsorption by BSMV-His VLPs. After two coatings, VLPs were thermally annealed at 200 °C and characterized via in situ TEM. Energy-dispersive X-ray spectroscopy (EDS) and high-angle annular dark-field (HAADF) analysis confirmed the conversion of the organic VLP core into amorphous carbon upon annealing. In situ TEM revealed grain boundary reduction in the Pd coating due to Ostwald ripening during thermal processing.
