3-DIMENSIONAL CONFORMATION OF THE EPITOPES OF HUMAN SUPEROXIDE DISMUTASE-2 RECOGNIZED BY ANTIBODY AGAINST HIV-1P17

We have previously reported that antibodies against HIV-1p17 protein c ross-react with human superoxide dismutase-2 (SOD-2). To identify and characterize the epitopes of human SOD-2 recognized by anti-HIV-1p17 a ntibody, we synthesized several peptide fragments of human SOD-2 and f ound that the antibody did not bind to the LQPALK hexapeptide which is contained in both HIV-1p17 and human SOD-2. Instead, this antibody bo und to four peptides which contain amino acid sequences similar, but n ot identical, to the known epitopes of HIV-1p17. These peptides have t wo features in three-dimensional (3-D) conformation: two protruded car bohydrate side chains on the peptide chain or a concave structure in t he molecule. It is suggested that the antibody does not strictly recog nize the amino acid sequence itself, but may recognize these 3-D confo rmations.