Complexation of peptide with Cu2+ responsible to inducing and enhancing the formation of alpha-helix conformation.

Role of some metal ions on the conformations of peptides was examined by using a series of short alanine-based peptides with single Trp-His (W-H) interaction in different environments. Circular dichroism (CD), Trp (W) fluorescence emission, and Fourier transform infrared (FTIR) spectroscopy revealed that there is a conformational role of Cu2+ in inducing and enhancing the formation of alpha-helix conformation. The complexation of the peptide with Cu2+ is responsible to the conformational effect because the chelation is able to stabilize peptide with an alpha-helix conformation. The possible factors affecting the role of Cu2+ are discussed in the paper. The results in this paper are useful to understand the important structural role of Cu2+ in protein folding and the possible mechanism in some neurodegenerative diseases such as Alzheimer's disease.