A CYCLIC PEPTIDE T ANALOGUE WITH HIGH CHEMOTACTIC ACTIVITY

Peptide T is an octapeptide (H-Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr-OH) based on a consensus sequence that has been identified in HIV proteins. Two conformationally-restricted analogues of peptide T fragment (H-Thr-Thr-Asn-Tyr-Thr-OH) were synthesized by cyclisation of the N-terminal amino group of Thr to the α- or β-carboxyl moiety of Asp introduced at the C-terminus of the peptide. The cyclo Thr-Thr-Asn-Tyr-Thr-Asp(OH) (Cα) showed high in vitro chemotactic activity, whereas the conformational restriction introduced into Thr-Thr-Asn-Tyr-Thr-Asp-OH was incompatible with the CD4 receptor. The cyclic analogue Cα was more active than its ester and the open-chain reference compound H-Thr-Thr-Asn-Tyr-Thr-Asp-OH. It also proved to be highly resistant to degradation by plasma or brain enzymes. © 1992.