KollagenAlphaKetten

KollagenAlphaKetten are the polypeptide chains that assemble to form collagen molecules, the main structural proteins of the extracellular matrix in animals. They are long, fibrous polypeptides that come together to create a stable triple helix, providing tensile strength to tissues such as skin, bone, tendons, and ligaments.

Each collagen molecule is built from three alpha chains. The specific combination of chains, and thus the collagen type, determines the tissue properties. For example, type I collagen consists of two alpha1 chains and one alpha2 chain, whereas other types may be formed from different alpha chains or even homotrimers. The alpha chains are encoded by a large family of COL genes (for example COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, COL11A1, and others). These genes produce precursor chains that undergo extensive post-translational modifications, including hydroxylation of proline and lysine residues and glycosylation, which are essential for stability.

Synthesis begins inside cells (fibroblasts in many tissues), where the chains assemble into procollagen with additional propeptide regions. The procollagen is secreted and then processed extracellularly by specific proteases to form mature collagen, which further assembles into fibrils and networks. Cross-linking by the enzyme lysyl oxidase strengthens these structures.

KollagenAlphaKetten play a fundamental role in tissue integrity and signaling. Mutations in COL genes can disrupt collagen synthesis or structure, contributing to connective tissue disorders such as osteogenesis imperfecta and certain forms of Ehlers-Danlos syndrome. The diversity of alpha chains allows collagen to fulfill a wide range of mechanical and architectural roles across tissues.