Fig. 5. Similarity of BBP to secondary structures. (A). β-Turns in the leucine-loop and tyrosine-loop. The β-turn present in the tyrosine-loop of 10 is further stabilized by a hydrogen bond connection with the alanine-bridge, generating an unusual β-turn geometry. (B). Double turn α-helix with 1^st, 2^nd and 7^th side chain highlighted and the corresponding BBP 16 shown in side-view (left) and top view (right). (C). Double turn α-helix with 1^st, 3^rd and 7^th side chain highlighted and the corresponding BBP 1 shown in side-view (left) and top view (right).