Fig. 3. NMR summaries, 20 lowest energy structures, Ramachandran plots and turn types in water for fourteen cyclic tetrapeptides: 5–7, 9, 13, 15, 17–24 in H₂O/D₂O (9 : 1) at 298 K. Compounds 5, 13, 17, 18, 21–24 form one hydrogen bond; while 6, 7, 9, 15, 19, 20 form two hydrogen bonds.