1.D.164.  The Cell-penetrating Amphipathic Peptide, Pep-1 (Pep-1) Family

Pep-1 delivers proteins and peptides into mammalian cells (Deshayes et al. 2004).  It is an amphipathic peptide of 21 residues, which was designed on the basis of a protein-interacting domain associated with a nuclear localization sequence, separated by a linker. This peptide carrier constitutes a tool for the delivery of active proteins and peptides, both in cultured cells and in vivo, without requiring covalent coupling. Deshayes et al. 2004 examined the conformational states of Pep-1 in its free form and complexed with a cargo peptide and investigated their ability to interact with phospholipids and the structural consequences of these interactions. From the conformational point of view, Pep-1 behaves differently from other similarly designed cell-penetrating peptides. CD analysis revealed a transition from a nonstructured to a helical conformation upon increase of the concentration. Determination of the structure by NMR showed that in water, its alpha-helical domain extends from residues 4-13. CD and FTIR indicated that Pep-1 adopts a helical conformation in the presence of phospholipids. Adsorption measurements performed at the air-water interface were consistent with the helical form. Pep-1 does not undergo conformational changes upon formation of a particle with a cargo peptide. A partial conformational transition occurs when the complex encounters phospholipids. Deshayes et al. 2004 proposed that the membrane crossing process involves formation of a transient transmembrane pore-like structure. Conformational change of Pep-1 is not associated with complexation with its cargo but is induced upon association with the cell membrane.



Deshayes, S., A. Heitz, M.C. Morris, P. Charnet, G. Divita, and F. Heitz. (2004). Insight into the mechanism of internalization of the cell-penetrating carrier peptide Pep-1 through conformational analysis. Biochemistry 43: 1449-1457.