Specific hydrogen bonding interactions of the best designs for 5 (A, B, C) and 7 (D, E, F). Helix (res:150–163) is shown for reference. For 5, specific hydrogen bonds are made from S159, S167 and N65. For 7, specific hydrogen bonds are made by S32 and Q109, and favorable close polar-polar interactions are also made from S67 and Y177.