Fine characterization of the antigenic site within the flap region in the protease protein of HIV-1

Summary.

 The aspartate protease encoded by human immunodeficiency virus type 1 is essential for cleavage of the gag and gag-pol precursor proteins. The majority of HIV-1-antibody-positive sera react with the protease. In this study we used a substitution set of peptides for detailed characterization of the earlierdefined antigenic site (aa 44–58) within the central “flap”region, also important in the context of conformationalflexibility during protease inhibitor binding. We found thatisoleucine at position 54 was important for creating anantigenic site required for binding of anti-HIV-1 sera. The identification of structurally essential amino acids in theflap region of HIV-1 PR may have important implications infuture development of antiviral drugs.