The position of the cell penetrating peptide penetratin in SDS micelles determined by NMR

Penetratin is a 16 residue peptide, RQI KIWFQ NRRMK WKK-amide, with the abi lity to penetrate cell membranes and a sequence taken from the homeodomain of the Drosophila Antennapedia transcription factor. 600 MHz H-1-nuclear ma gnetic resonance has been used to study the structure and location of penet ratin interacting with a sodium dodecyl sulphate micelle. The positioning o f penetratin in the micelle was studied by adding paramagnetic probes (Mn2 ions, 5-doxyl and 12-doxyl stearic acid) to the solvent. The results show that the peptide is a straight helix positioned with its C-terminus deep in side the micelle and its N-terminus near the surface of the micelle. (C) 20 01 Published by Elsevier Science B,V. on behalf of the Federation of Europe an Biochemical Societies.