1. The most prevalent protein in the animal kingdom responsible for the structure and integrity of most tissues.
2. Form: a protein containing domains of triple-helical conformation. Characterized by repetitive Gly-X-Y sequences where glycine is in every third residue, and stabilized by proline and hydroxyproline residues.
3. Function: a protein that participates in formation of extracellular aggregates which are primarily supporting elements.