Synthesis and evaluation of Glypsi(PO(2)R-N)Pro-containing pseudopeptides as novel inhibitors of the human cyclophilin hCyp-18.
The human cyclophilin hCyp-18, an abundant peptidyl-prolyl cis-trans isomerase (PPIase) implicated in protein folding, controls the infection of CD4(+) T-cells by HIV-1, the pathologic agent of AIDS. Therefore, hCyp-18 is an interesting target for the development of novel anti-HIV-1 therapeutics. We focused on the design of transition-state analogue inhibitors of the PPIase activity of cyclophilin. Most experimental results reported in the literature suggest that hCyp-18 catalyzes the pyramidalization of the nitrogen of pyrrolidine via an H-bond network which results in the deconjugation of the amino acyl-prolyl peptide bond. We proposed the Glypsi(PO(2)R(1)-N)Pro motif (R = alkyl or H) as a selective transition-state analogue inhibitor of cyclophilin. This motif was inserted in Suc-Ala-Ala-Pro-Phe-pNA, a peptide substrate of hCyp-18. The pseudopeptide Suc-Ala-Glypsi(PO(2)Et-N)Pro-Phe-pNA 1b bound to hCyp-18 (K(d) = 20 +/- 5 microM) and was able to selectively inhibit its PPIase activity (IC(50) = 15 +/- 1 microM) but not hFKBP-12, another important PPIase. Deprotection of the phosphonamidate moiety resulted in a complete lack of inhibition. We previously demonstrated that reduction of the Phe-pNA moiety caused a quantitative reduction of the affinity; however, Suc-Ala-Glypsi(PO(2)Et-N)Pro-Phepsi(CH(2)-NH)pNA 7b still bound and inhibited hCyp-18, suggesting that the Glypsi(PO(2)Et-N)Pro motif plays the major role in the binding to cyclophilin. Consequently, we propose compound 1b as being a novel transition-state mimic inhibitor of hCyp-18.
CEA/Saclay, Département d'Ingénierie et d'Etudes des Protéines, Bâtiment 152, 91191 Gif-sur-Yvette, France.
Luc
L
Demange
Mireille
M
Moutiez
Christophe
C
Dugave
D000577:Amides / Q000737:chemistry; D021983:Cyclophilins / Q000037:antagonists & inhibitors* / Q000737:chemistry; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry; D006801:Humans; D018716:Molecular Mimicry; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry*; D063065:Organophosphonates / Q000737:chemistry
D000577:Amides; D004791:Enzyme Inhibitors; D009842:Oligopeptides; D063065:Organophosphonates; C437224:cyclophilin hCyp-18; C465461:succinyl-alanyl-glycyl-pseudo(PO2Et-N)prolyl-phenylalanine-4-nitroaniline; D021983:Cyclophilins