Collagen/collagen interaction sites involved in fibril formation. A, A schematic of collagen molecules interacting during fibril formation. Sites that are involved in collagen/collagen binding are indicated with red and blue boxes. These sites include the T-TBR (α1 776-796 fragment) and the α2Ct. B, A computer model representing interacting domains of two collagen molecules. The triple-helical fragment of the T-TBR is indicated in blue, while the fragment of the α2Ct of the interacting partner collagen molecule is indicated in red. Amino acid residues most likely engaged in collagen/collagen interaction are also indicated.