In primary keratinocytes from __SP__ , binding of a protein fragment ( 204 462 ) containing a ligand binding domain from __SP__ __NODE__ protein and a protein fragment ( 93 427 ) containing a ligand binding domain from __NODE__ protein is greater than binding of a protein fragment ( 204 462 ) containing a ligand binding domain from __SP__ __NODE__ protein and a mutant protein fragment ( 93 427 ) ( L233S with its ligand binding domain mutated ) from __NODE__ protein .