Abstract: As the wide applications of gold nanoparticles(GNPs) in various fields as the biochemistry and biomedicine, the present investigation is geared to the practical demand. Recently, the capability of sulphydryl carboxylate functionalized GNPs to promote the folding of a positive charged peptide into an α-helix was established. This design allowed favorable electrostatic interactions between the nanoparticles and the peptide when the positive charged residues were positioned in a cofacial manner along the helix and was responsible for the assisted folding observed. GNPs coated with different chain lengths of sulphydryl carboxylate are prepared by adding sulphydryl carboxylate into GNPs solution which is synthesized via reducing tetrachloroauric acid(HAuCl₄) by sodium borohydride. The structure of the functionalized GNPs can make it interact with electriferous proteins. Multiple spectral means have been used to study the interaction between the functionalized GNPs and melittin. The results show that the functionalized GNPs induced melittin to form α-helix by electrostatic interactions, and it is directly related with the chain length of sulphydryl carboxylate.

Key words: Functionalized gold nanoparticles, Melittin, α-Helix