Building collagen molecules, fibrils, and suprafibrillar structures

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Fibril-forming collagens are synthesized as procollagens with N- and C-terminal propeptides.
• These propeptides are crucial for proper collagen molecule assembly, secretion, and extracellular matrix organization.

Purpose of the Study:

• To review the roles of collagen propeptides in fibril formation, solubility, and shape control.
• To explore the implications of recent structural and ordering studies on collagen fibrillogenesis.

Main Methods:

• Literature review of collagen structure, assembly, and fibrillogenesis.
• Analysis of structural data for C-propeptide trimers.
• Discussion of models for fibril diameter control and liquid crystalline ordering.

Main Results:

• C-propeptides mediate intracellular chain association and ensure extracellular solubility.
• N-propeptides control fibril shape and diameter, with mechanisms explained by the radial packing model.
• Procollagen molecules exhibit liquid crystalline ordering in solution before fibril assembly.

Conclusions:

• Collagen propeptides play multifaceted roles in collagen processing and fibril formation.
• Liquid crystalline ordering may explain the hierarchical structures observed in connective tissues.