Selective Self-Assembly of Gold Nanocrystals using Complementary Leucine Zipper Peptides

A heterodimeric leucine zipper (Lz)–based peptide hybrid was utilized as a molecular adhesive to bound two types of gold nanocrystals with different shapes. An acidic leucine zipper (LzE) and a basic leucine zipper (LzK) peptides with terminal cysteine are respectively adsorbed to the surface of spherical gold nanoparticles (LzE–Au NPs) and gold nanocubes (LzK–Au NCs). Transmission electron microscope (TEM) observation and visible (Vis) absorption spectroscopy were revealed that LzE–Au NPs and LzK–Au NCs are selectively self-assembled in water. The dynamic self-assembly behavior is also confirmed by in-situ fluorescence resonance energy transfer between fluorescence dyes connected to LzE and LzK peptides and other control experiments. Complementary acidic leucine zipper (LzE) and basic leucine zipper (LzK) peptides were successfully adsorbed to the surface of spherical gold nanoparticles (Au NPs) and gold nanocubes (Au NCs), respectively. Selective self-assembly of LzE–Au NPs and LzK–Au NCs was occurred by hydrophobic interaction between leucine residues and electrostatic interaction between K (Lys) and E (Glu) amino acids.