MODEL OF PEPTIDE-T 3-DIMENSIONAL STRUCTURE

A 3D model is proposed for peptide T, an HIV reproduction inhibitor wi th amino acid sequence corresponding to a fragment of the T4 receptor- binding site of the viral protein gp120. The structure was modeled usi ng a method designed earlier [1] and based on combining the molecular mechanics algorithms and the NMR data. Six types of low-energy structu res were obtained which differed in the spatial folding of the peptide backbone. Ah types were shown to lack strict determination of the sid e group conformations, which can assume several states providing (with in the given type) about the same stabilization of the backbone. Despi te certain differences, all the structures selected were marked by two consecutive reverse turns of the polypeptide chain within the C-termi nal pentapeptide segment. This region is supposed to be responsible fo r peptide binding with the T4 receptor and for the antiviral effect.