Deriving the generic structure of the fibronectin type II domain from the prothrombin Kringle 1 crystal structure.

摘要: The proposed homology between the fibronectin type II domain and Kringle domains of blood clotting fibrinolytic proteins has been examined in three dimensions by substituting sequence into bovine prothrombin 1 tertiary structure, determined X-ray crystallographical methods at 3.8 A. Structural substitution aligned amino acids produces a compact chain fold deletions insertions are accommodated within modelled structure. This confirms structural two verifies alignment common evolution units. structures contain homologous hydrophobic cores, centered around disulphide bridges which link conserved beta-type strands. Gross differences occur exterior loops potential functional sites these regions as found fibronectin, Factor XII seminal fluid protein PDC-109 proposed. We suggest that evolved from ancestral comprising core arrangement later diverged to bind different macromolecules through adaptation external loops.