title: Structural constraints on the evolution of the collagen fibril: convergence on a 1014-residue COL domain.
abstract: Type I collagen is the fundamental component of the extracellular matrix. Its α1 gene is the direct descendant of ancestral fibrillar collagen and contains 57 exons encoding the rod-like triple-helical COL domain. We trace the evolution of the COL domain from a primordial collagen 18 residues in length to its present 1014 residues, the limit of its possible length. In order to maintain and improve the essential structural features of collagen during evolution, exons can be added or extended only in permitted, non-random increments that preserve the position of spatially sensitive cross-linkage sites. Such sites cannot be maintained unless the twist of the triple helix is close to 30 amino acids per turn. Inspection of the gene structure of other long structural proteins, fibronectin and titin, suggests that their evolution might have been subject to similar constraints.
authors.affiliation: School of Medicine, University of Cardiff, Tenovus Building, Cardiff CF14 4XN, UK slatterda@cardiff.ac.uk.
authors.forename: David Anthony
authors.initials: DA
authors.lastname: Slatter
authors.affiliation: Department of Biochemistry, Downing Site, University of Cambridge, Cambridge CB2 1QW, UK.
authors.forename: Richard William
authors.initials: RW
authors.lastname: Farndale
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids; D000818:Animals; D005075:Biological Evolution; D003094:Collagen / Q000737:chemistry* / Q000235:genetics; D006801:Humans; D008958:Models, Molecular; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs / Q000235:genetics
chemical_list: D000596:Amino Acids; D003094:Collagen
keywords: D-period; collagen; cross-links; exon structure