SULFONATED ANALOGS OF CYCLOLINOPEPTIDE-A - SYNTHESIS, IMMUNOSUPPRESSIVE ACTIVITY AND CD STUDIES

Linear and cyclic analogues of cyclolinopeptide A (CLA in which one or both phenylalanine residues in fragment Pro(6)-Pro(7)-Phe(8)-Phe(9) w ere substituted by their sulfonated derivatives have been synthesized by SPPS method and cyclization with the BOP reagent. The peptides were examined for their immunosuppressive activity in the humoral and cell ular immune response by PFC and DTH tests. All of the analogues retain some immunosuppressive activity of native CLA. Their CD spectra confi rm that the optical activity of aromatic residues in CLA depends on th eir position in the peptide chain. Only the residue in position 8 seem s to be optically active. CD spectrum of the cyclic analogue modified in position 9 is very similar to that of native CLA which correlates w ith its high biological activity. The chiroptical properties of the p- sulfonated Phe-residue are established. (C) Munksgaard 1997.