title: Reversible chirality control in peptide-functionalized gold nanoparticles.
abstract: We report the induction of chiroptical properties in 2 nm diameter gold nanoparticles passivated with short peptides characterized by the Aib-l-Ala repetition in their sequence. The nanoparticles present relevant ECD signals in the 300-650 nm wavelength region, corresponding to the gold nanoparticle's quantized electronic structure. Although the only chiral amino acid present in the peptide sequences is l-Ala, the particles show mirror image spectra like those of enantiomers according to the number of amino acids in the main chain (odd or even). Such a behavior appears to be strongly influenced by the secondary structure assumed by the peptides when passivating the nanoparticles and vanishes when the sequence is long enough to assume a 310-helix conformation. Moreover, chirality control is a reversible process and can be deactivated or reactivated by increasing or decreasing the temperature.
authors.affiliation: Department of Chemical Sciences, University of Padova , Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Longo
authors.forename: Andrea
authors.initials: A
authors.lastname: Orlandin
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Mancin
authors.forename: Paolo
authors.initials: P
authors.lastname: Scrimin
authors.forename: Alessandro
authors.initials: A
authors.lastname: Moretto
mesh_terms: D000409:Alanine / Q000737:chemistry; D002942:Circular Dichroism; D006046:Gold / Q000737:chemistry*; D006860:Hydrogen Bonding; D053768:Metal Nanoparticles / Q000737:chemistry*; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods; D010455:Peptides / Q000737:chemistry; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D010455:Peptides; D006046:Gold; D000409:Alanine