PMID: 1544894

 

    Legend: Sugar

Title : O-linked fucose is present in the first epidermal growth factor domain of factor XII but not protein C . Epidermal growth factor ( EGF ) domains are found in many proteins , particularly those of the coagulation/fibrinolytic system

Abstract :

1. We and others have demonstrated that tissue plasminogen activator ( t-PA ) and prourokinase are modified by the attachment of fucose to equivalent threonine residues within their EGF domains
2. Factor XII and protein C each contain two EGF domains ; in both proteins , the EGF domain nearest the N terminus has a threonine residue in a position homologous to that which is fucosylated in t-PA
3. In protein C , this site is 3 residues from the position of another post-translational modification, beta-hydroxylation of Asp-71
4. We isolated peptides containing these sites to determine, primarily by mass spectrometric analysis, the presence of O-linked fucose and/or beta-hydroxyaspartate
5. We found that factor XII is fully fucosylated at Thr-90
6. Protein C is unmodified at the equivalent site ( Thr-68 ) and is completely beta-hydroxylated at Asp-71
7. It has been recently reported that the first EGF domain of human factor VII has O-linked fucose at the equivalent position ( Ser-60 ) (Bjoern, S., Foster, D. C., Thim, L., Wiberg, F. C., Christensen, M., Komiyama, Y., Pedersen, A. H., and Kisiel, W. (1991) J. Biol
8. Chem
9. 266, 11051-11057), while it is unmodified at Asp-63 despite having the consensus sequence for beta-hydroxylation at the latter site
10. These observations raise the possibility that O-linked fucosylation and beta-hydroxylation of EGF domains are mutually exclusive post-translational modifications