Collagen suprastructures

Collagens area family of proteins with considerable molecular diversity. The genetic diversity is increased by assembly of multiple isoforms, alternative splicing and post-translational modifications. All collagen molecules share common features, including having at least one domain composed of three polypeptide chains organized as a triple helix. However, these molecules assemble to form a variety of supramolecular structures, e.g., fibrils, filaments, or networks, responsible for the characteristics of specific extracellular matrices. These supramolecular structures are alloys or macromolecular composites, containing different collagen types as well as other matrix macromolecules. This heteropolymeric composition provides an additional level of complexity. Current concepts of collagen supra-structures, their assembly and function within extracellular matrices will be the focus of this review.