SPECIFIC INTERACTION BETWEEN CYCLOPHILIN AND CYCLIC-PEPTIDES

Cyclophilin A, a peptidyl-prolyl cis-trans isomerase that catalyzes th e otherwise slow isomerization of Xaa-Pro imidic bond, specifically, b inds the immunosuppressant cyclosporin A. Herein we repel evidence on binding of cyclolinopeptide A and its synthetic analogue, [Aib(5,6)-D- Ala(8)] cyclolinopeptide, to bovine cyclophilin A. Binding experiments were monitored by fluorescence, CD, and second-derivative spectroscop ies, evidencing no remarkable rearrangement of protein structure organ ization. The possibility, that cyclolinopeptide A could act as a subst itute of cyclosporin A in the immunosuppression modulation is also bri efly discussed. (C) 1995 John Wiley and Sons, Inc.