Dimerization of helical β-peptides in solution.

Molecular simulations are used to examine the aggregation behavior of several β-peptides in explicit water. The particular peptides considered here adopt a helical, rodlike conformation in aqueous solution. Four distinct molecular sequences are considered. Earlier experimental studies have revealed the formation of ordered and disordered aggregates for such molecules, depending on sequence. The simulations reported here, which are conducted by resorting to metadynamics techniques, lead to free energy surfaces for dimerization of the peptides in water as a function of separation and relative orientation. Such surfaces are used to identify the molecular origins for the behaviors observed in the experiments.