Structure and dynamics of angiotensin (1-7) vasoactive peptide in aqueous solution at the density-functional based tight-binding level

Structure and dynamics of heptapeptide Angiotensin (1-7) in aqueous solution have been investigated by means of density-functional based tight-binding molecular dynamics simulations. Solvent-solute interactions have been studied using a hybrid QM/MM method. The backbone of the heptapeptide remains relatively rigid in aqueous solution compared to gas phase. The solvent acts as a cushion, preventing the free motion of the molecule. Tyrosine is the residue which presents the smallest flexibility and the largest number of water molecules in its first solvation shell. This is in good agreement with the previously published NMR results. The intra- and intermolecular hydrogen bridges have been quantified and analyzed in terms of conformation and stability.