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An unusual pattern of peptide-bound lysine metabolism in collagen from an infant with lethal perinatal osteogenesis

O M Petrovic, E J Miller

    The Journal of Clinical Investigation
    |June 1, 1984
    PubMed

    Insights

    Infants with type II osteogenesis imperfecta have collagens with lower positive charge due to reduced lysine. This suggests abnormal collagen fibril formation increases lysyl oxidase activity.

    Area of Science:

    • Biochemistry
    • Molecular Biology
    • Genetics

    Background:

    • Osteogenesis imperfecta (OI) is a group of genetic disorders characterized by bone fragility.
    • Type II OI, a lethal perinatal form, involves severe skeletal deformities.
    • Collagen, the primary structural protein in bone and connective tissues, is crucial for skeletal integrity.

    Observation:

    • Collagens from various tissues of a type II OI infant showed normal proportions but altered chemical characteristics.
    • Dermal collagen chains (alpha 1(I), alpha 2(I), alpha 1(III), alpha 1(V), alpha 2(V)) exhibited a lower positive charge compared to normal tissues.
    • Amino acid analysis revealed a deficiency of 5-7 lysyl residues in these collagen chains.

    Findings:

    • The reduced lysyl residues were attributed to elevated levels of allysine, a lysine-derived cross-linking precursor.
    • Lysyl oxidase activity, responsible for forming allysine from lysine, appeared to be increased.
    • Aberrant collagen fibril formation in type II OI may facilitate enhanced lysyl oxidase activity.

    Implications:

    • Understanding collagen alterations in type II OI can provide insights into disease pathogenesis.
    • The findings suggest a potential link between fibril structure defects and altered post-translational modification.
    • Further research into lysyl oxidase regulation in OI could reveal therapeutic targets.

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