A novel class of cell-penetrating, nucleolar-targeting peptides (NrTPs), was recently developed from the rattlesnake venom toxin crotamine. Based on the intrinsic fluorescence of tyrosine or tryptophan residues, the partition of NrTPs and crotamine to membranes with variable lipid compositions was studied. Partition coefficient values (in the 10(2)-10(5) range) followed essentially the compositional trend POPC:POPG≤POPG

This work was funded by the Portuguese Ministry of Education and Science (Fundação para a Ciência e a Tecnologia, FCT-MEC; including M.R. and A.S. fellowships SFRH/BD/37432/2007 and SFRH/BPD/26821/2006, respectively), the Spanish Ministry of Economy and Competitiveness (MINECO, grant SAF2011-24899), Generalitat de Catalunya (2009 SGR 492), FP7-PEOPLE IRSES (International Research Staff Exchange Scheme) project MEMPEPACROSS (European Union), and the European Biophysical Societies’ Association (EBSA).