[structure: see text] Collagen is the most abundant protein in animals. Interstrand N-H...O=C hydrogen bonds between backbone amide groups form a ladder in the middle of the collagen triple helix. Isosteric replacement of the hydrogen-bond-donating amide with an ester or (E)-alkene markedly decreases the conformational stability of the triple helix. Thus, this recurring hydrogen bond is critica...
