One of the important regulators of aldosterone secretion and effector controlling blood pressure is angiotensin II. It acts through two main receptors: AT1R (the angiotensin II type-1 receptor) and AT2R. Second one, AT2R, is a promising target for anticancer drugs. Magnani and co-workers [1] have demonstrated that selectivity towards AT2R (and not to AT1R) can be enhanced in peptides with large population of cis peptide bond preceding proline (Pro7 in angiotensin II). Accordingly, the replacement of His6 by aromatic residues with different propensities can form CH/π interactions with Pro7. In order to design new angiotensin derived AT2R ligands we have carried out molecular simulations of model peptides Ace-Xxx-Pro-Nme, with tyrosine, phenylalanine, 4-nitrophenylalanine and O-phosphotyrosine as Xxx. Cis/trans isomerisation takes place in tens to hundreds millisecond time scales, which is hardly accessible in classical unbiased simulations. Therefore, we used metadynamics [2] to predict equilibrium populations of cis peptide bond. Populations of cis peptide bond determined by 400 ns well-tempered metadynamics simulations were predicted as: 17 ± 3 % (exp. 40 %) for tyrosine, 35 ± 6 % (exp. 25 %) for O-phosphotyrosine, 20 ± 4 % (exp. 20 %) for phenylalanine and 14 ± 4 % (exp. 5 %) for 4-nitrophenylalanine, respectively (mean ± s.d.) as Xxx. The accuracy of these results are currently being improved by combination with Flying Gaussian metadynamics, the new method developed by our group.