Role of the amino‐terminal extrahelical region of type I collagen in directing the 4D overlap in fibrillogenesis

The amino‐terminal telopeptide of the collagen α1(I) chain has a highly conserved sequence. This sequence was analyzed by the Chou‐Fasman criteria, and a folded β‐sheet conformation, including a β‐turn, was predicted. This folded “hairpin” region favors both ionic and hydrophobic intermolecular interactions with α1(I) chain residues 930–938 on a neighboring, end‐overlapped molecule. An end‐overlap interaction of this nature could direct the initial step in fibril formation. The predicted structure also places the potential crosslink‐forming lysyl residue, 9 N , in a unique site at the β‐turn end of the telopeptide.