Collagen protein axial periodicity is -: (A) 67nm, (B) l07nm, (C) 207nm, (D) 307nm
Answer is A. Ans. is 'a' i.e., 67 nm.The fibrillogenesis involves the lateral association of collagen triple helices, the structural unit of collagen, to form long, smooth fibrils with a characteristic 67-nm axial structural feature known as the D-periodicity or axial periodicity.