Physalaemin (PHY) is known to take on both a linear and helical three dimensional structure. Grace et al. (2010) have shown that in aqueous environments,  PHY preferentially takes on the linear conformation whereas in an environment that simulates a cellular membrane, PHY takes on a helical confirmation from the Pro residue to the C-Terminus. This helical conformation is essential to allow the binding of PHY to neurokinin-1 (NK1) receptors. Consensus sequences between Substance P (a mammalian tachykinin and agonist of NK1) and PHY have been used to confirm that the helical confirmation is necessary for PHY to bind to NK1.