A recognition site on synthetic helical oligonucleotides for monoclonal anti-native DNA autoantibody.

The binding site in native DNA for a murine monoclonal anti-DNA autoantibody was investigated by measurements of competitive binding of a series of synthetic helical oligonucleotides. The antibody bound to a (dG-dC)3 or (dG-dC)4 core in the center of a base-paired octadecanucleotide. Reactions of analogues containing modifications or substitutions at specific sites indicated that the antibody bound to portions of cytosine and guanine in the major groove, a limited region of the backbone, and the 2-amino group of one guanine in the minor groove. For these interactions to occur, the antibody combining site would straddle the backbone of one of the helical strands of DNA.