The peculiar collagens of mussel byssus

Matrix Biol. 1998 Jun;17(2):93-106. doi: 10.1016/s0945-053x(98)90023-3.

Abstract

The byssal collagens of marine mussels are extracorporeal collagens that function in byssal threads under tension. Each byssal thread resembles a shock absorber in its mechanical design: it is strong and stiff at one end and pliably elastic at the other. Primary structures of three of these collagens (preCols), deduced from cDNAs, reveal signal peptide sequences, but no N-glycosylation sites or propeptides typical of procollagens. The collagen domain (40-50 kDa) represents roughly half the mass of the mature molecules and is distinguished by its central location, abundant Gly-Gly-X repeats, and "flaws" (usually Gly deletions). Flanking the collagen domains on both sides are structural domains that resemble elastin in preCol-P, spider drag-line silk in preCol-D, and Gly-rich cell wall proteins in preCol-NG. Not surprisingly, studies of preCol distribution in byssal threads suggest preCol-P enhancement in the elastic proximal portion, while preCol-D predominates in the stiffer distal portion. PreCol-NG, in contrast, is evenly distributed. Although no data are yet available on the fibrillogenesis and cross-linking of the preCols, the quarter-stagger assembly of fibrillar interstitial collagens does not pertain since preCols lack the terminal peptides of tropocollagen. Metal-binding by histidines may mediate the initial inter- and intramolecular stabilization of preCols in the byssus.

Publication types

  • Review

MeSH terms

  • Animals
  • Base Sequence
  • Collagen* / chemistry
  • Collagen* / genetics
  • Collagen* / metabolism
  • Cross-Linking Reagents
  • Mice
  • Molecular Sequence Data
  • Muscle, Skeletal / metabolism*

Substances

  • Cross-Linking Reagents
  • Collagen