- Substitution of serine for glycine 883 in the triple helix of the pro alpha 1 (I) chain of type I procollagen produces osteogenesis imperfecta type IV and introduces a structural change in the triple helix that does not alter cleavage of the molecule by procollagen N-proteinase. Lightfoot, S.J., Atkinson, M.S., Murphy, G., Byers, P.H., Kadler, K.E. J. Biol. Chem. (1994)









