Generation of a cell-permeable cycloheptapeptidyl inhibitor against the peptidyl–prolyl isomerase Pin1

Cyclic peptides are capable of binding and modulating challenging drug targets including protein–protein interactions. However, their lack of membrane permeability prevents their application against intracellular targets. In this study, we show that it is possible to design a cell-permeable and biologically active cycloheptapeptide inhibitor against the intracellular enzyme peptidyl–prolyl isomerase Pin1 by integrating cell-penetrating and target-binding sequences.