R5 peptide is one of the repeating peptide sequences that form the protein diatom in Cylindrotheca fusiformis. R5 peptide can be used as a template for the synthesis of Pd (palladium) nanoparticles (NPs). R5 peptide forms complexes with metal ions through the amine groups in its sequence, and the self-assembled structure of the peptide provides a confined spatial environment for the reduction of metal ions and the nucleation of nanoparticles. R5 peptide can be used in the research of biomimetic nanomaterials.