The tripeptide sequence Trp-Lys-Ser (WKS) is repeated three times in the extracellular ligand binding domain of human Tissue Factor (TF). Using site-directed mutagenesis, we replaced each of the WKS motifs in human TF by Arg-Lys-Gly (RKG), the least conserved replacement for the motif found in murine TF. This substitution in the first repeat W14KS, as well as a Trp14→Arg substitution, resulted in a structurally altered protein, whereas a conservative hydrophobic Trp14→Phe substitution resulted in a functionally normal protein. This suggests that Trp14 may contribute to a hydrophobic core rather than involvement of this motif in function. Replacement of the W45KS and W158KS motifs was associated with no detectable structural alterations; however, function was diminished with the RKG replacement of the third repeat. Mutant proteins with Lys159→Ala and Tyr157→Ala substitutions exhibited loss of function, whereas Tyr156→Ala and Ser160→Ala substitutions flanking the YWK sequence resulted in functional proteins. These data demonstrate that the W158KS motif in human TF is associated with a functional site and identify Lys159 in this motif as a functionally important residue.
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Research Article| March 15 1992
The third Trp-Lys-Ser (WKS) tripeptide motif in tissue factor is associated with a function site
D J Miles;
Biochem J (1992) 282 (3): 737–740.
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A Rehemtulla, W Ruf, D J Miles, T S Edgington; The third Trp-Lys-Ser (WKS) tripeptide motif in tissue factor is associated with a function site. Biochem J 15 March 1992; 282 (3): 737–740. doi: https://doi.org/10.1042/bj2820737
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