Self-assembled peptide nanotubes from first principles

Nanotubular structures made up of polypeptides have recently become available. We present a characterization of the structural and electronic properties of one such system within density functional theory with calculations using gradient-corrected exchange-correlation functionals. Comparison with data on natural amino acids, and with the predictions of empirical models, is drawn from the structural features. A large gap in the low-energy electronic excitation spectrum is predicted, and the presence of extended as well as localized states near the gap is found.