beta-sheet preferences from first principles

The natural amino acids have different preferences of occurring in specific types of secondary protein structure. Simulations are performed on periodic model â-sheets of 14 different amino acids, at the level of density functional theory, employing the generalized gradient approximation. We find that the statistically observed â-sheet propensities correlate very well with the calculated binding energies. Analysis of the calculations shows that the â-sheet propensities are determined by the local flexibility of the individual polypeptide strands.