Synthesis of an Uncharged Tetra-cyclopeptide Acting as a Transmembrane Carrier: Enhanced Cellular and Nuclear Uptake.

A small uncharged cyclopeptide scaffold inspired by a natural product and designed to undergo postfunctionalizations was used as a new transmembrane vector. A bioactive and fluorescent triazole aminocoumarin was bound to this carrier to facilitate its moving across cell and subcellular membranes, and this led to an increase in its cell toxicity.