THE CONFORMATIONAL STUDIES ON THE HETERODETIC CYCLIC ANALOGS OF THYMOPENTIN

Solution conformations of three heterodetic cyclic analogues of thymop entin (TP5), Mpa-Arg-Lys-Asp-Val-Tyr-CysNH2, Mpa-Arg-Lys-D-Pro-Val-Tyr -CysNH2, and Mpa-Arg-Lys-Asp-Val-Pro-CysNH2, each containing the disul fide bridge formed between the terminal residues, were investigated by CD and NMR spectroscopic methods, as well as by molecular dynamics st udies. It was found that only the first of the peptides mentioned, whi ch is also similar to TP5 in respect of its biological activity, demon strates conformational preferences similar to TP5, i.e. preference for the folded structure with a gamma-turn localized on the Asp3 residue.