title: The role of the epidermal growth factor-1 and hydrophobic stack domains of human factor IX in binding to endothelial cells.
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.
authors.affiliation: Department of Biology, University of North Carolina, Chapel Hill 27599.
authors.forename: W F
authors.initials: WF
authors.lastname: Cheung
authors.forename: D L
authors.initials: DL
authors.lastname: Straight
authors.forename: K J
authors.initials: KJ
authors.lastname: Smith
authors.forename: S W
authors.initials: SW
authors.lastname: Lin
authors.forename: H R
authors.initials: HR
authors.lastname: Roberts
authors.forename: D W
authors.initials: DW
authors.lastname: Stafford
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002460:Cell Line; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D004730:Endothelium, Vascular / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000737:chemistry; D005164:Factor IX / Q000737:chemistry / Q000378:metabolism*; D005170:Factor X / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012995:Solubility; D013329:Structure-Activity Relationship; D014162:Transfection
chemical_list: D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D004815:Epidermal Growth Factor; D005164:Factor IX; D005170:Factor X; D002118:Calcium