[Model of the spatial structure of peptide T]

The spatial structure model of peptide T (AIDS reproduction inhibitor, the amino acid sequence of which corresponds to the fragment into the binding site of the virus protein gp120 with T4 receptor) is proposed. Peptide structure modelling has been carried out by the previously developed method based on joint usage of the molecular mechanics algorithms and NMR spectroscopy data. To build the model, two-dimensional nuclear Overhauser effect spectroscopy data for RNase A homologous fragment 22-26 were taken from the literature. The result of the presented work was a set consisting of six types of low-energy structures with different spatial packing of the peptide main chain. All structural types have been shown to be characterized by the lack of strict determination of the side chain conformations of the amino acid residues that can be realized in a few states providing approximately equal (within the given type) stabilization of one main chain form. At the same time, despite the definite differences, all of the selected structures were characterized by the presence of two consecutive reverse polypeptide chain turns at the C-terminal pentapeptide fragment. This site is supposed to be responsible for the peptide binding with T4 receptor and the antiviral effect.