The role of the epidermal growth factor-1 and hydrophobic stack domains of human factor IX in binding to endothelial cells. |
| |
Authors: | W F Cheung D L Straight K J Smith S W Lin H R Roberts D W Stafford |
| |
Affiliation: | Department of Biology, University of North Carolina, Chapel Hill 27599. |
| |
Abstract: | To determine the function and specificity in factor IX of the first epidermal growth factor (EGF)-like domain and the eight-amino acid hydrophobic stack encoded by exon C (residues 39-46), these domains were replaced by the corresponding polypeptide regions of factor X and chimeric proteins were produced in human embryo kidney cells. Both chimeras were activated by factor XIa at a rate similar to plasma factor IX and exhibited calcium-dependent fluorescence quenching similar to plasma factor IX. Both chimeras competed equally for binding to the endothelial cell receptor. Our findings make it unlikely that the first EGF-like domain or the hydrophobic stack of factor IX are responsible for the specific binding of factor IX to its endothelial cell receptor. |
| |
Keywords: | |
|