Binding of a protein fragment ( 613 752 ) containing a LXXLL motif 1 ( aa sequence LLQLL ) and a LXXLL motif 2 ( aa sequence LHKLL ) and a LXXLL motif 3 ( aa sequence LRYLL ) and a receptor binding domain from __NODE__ protein and mutant __NODE__ protein ( L276A V280A ) does not occur in a cell free system .