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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/94149
- Conformation and orientation of penetratin in phospholipid membranes
- Clayton, A. H. A.; Atcliffe, B. W.; Howlett, G. J.; Sawyer, W. H.
- The binding, conformation and orientation of a hydrophilic vector peptide penetratin in lipid membranes and its state of self-association in solution were examined using circular dichroism (CD), analytical ultracentrifugation and fluorescence spectroscopy. In aqueous solution, penetratin exhibited a low helicity and sedimented as a monomer in the concentration range ~50-500 μM. The partitioning of penetratin into phospholipid vesicles was determined using tryptophan fluorescence anisotropy titrations. The apparent penetratin affinity for 20% phosphatidylserine/80% egg phosphatidylcholine vesicles was inversely related to the total peptide concentration implying repulsive peptide-peptide interactions on the lipid surface. The circular dichroism spectra of the peptide when bound to unaligned 20% phosphatidylserine/80% egg phosphatidylcholine vesicles and aligned hydrated phospholipid multilayers were attributed to the presence of both α-helical and β-turn structures. The orientation of the secondary structural elements was determined using oriented circular dichroism spectroscopy. From the known circular dichroism tensor components of the α-helix, it can be concluded that the orientation of the helical structures is predominantly perpendicular to the membrane surface, while that of the β-type carbonyls is parallel to the membrane surface. On the basis of our observations, we propose a novel model for penetratin translocation.
- Publication type
- Journal article
- Journal of Peptide Science, Vol. 12, no. 3 (Mar 2006), pp. 233-238
- Publication year
- FOR Code(s)
- 0304 Medicinal and Biomolecular Chemistry
- Circular dischroism; Oriented circular dischroism; Peptide-lipid interactions; Vector peptides
- John Wiley & Sons
- Publisher URL
- Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd. The publisher does not allow institutions to archive either the accepted manuscript or the published version of the article.
- Peer reviewed