title: The impact of cell-penetrating peptides on membrane bilayer structure during binding and insertion.
abstract: We have studied the effect of penetratin and a truncated analogue on the bilayer structure using dual polarisation interferometry, to simultaneously measure changes in mass per unit area and birefringence (an optical parameter representing bilayer order) with high sensitivity during the binding and dissociation from the membrane. Specifically, we studied penetratin (RQIKIWFQNRRMKWKK), along with a shortened and biotinylated version known as R8K-biotin (RRMKWKKK(Biotin)-NH2). Overall both peptides bound only weakly to the neutral DMPC and POPC bilayers, while much higher binding was observed for the anionic DMPC/DMPG and POPC/POPG. The binding of penetratin to gel-phase DMPC/DMPG was adequately represented by a two-state model, whereas on the fluid-phase POPC/POPG it exhibited a distinctly different binding pattern, best represented by a three-state kinetic model. However, R8K-biotin did not bind well to DMPC/DMPG and showed a more transitory and superficial binding to POPC/POPG. Comparing the modelling results for both peptides binding to POPC/POPG suggests an important role for a securely bound intermediate prior to penetratin insertion and translocation. Overall these results further elucidate the mechanism of penetratin, and provide another example of the significance of the ability of DPI to measure structural changes and the use of kinetic analysis to investigate the stages of peptide-membrane interactions.
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800,Australia.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hirst
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800,Australia.
authors.forename: Tzong-Hsien
authors.initials: TH
authors.lastname: Lee
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800,Australia.
authors.forename: Ketav
authors.initials: K
authors.lastname: Kulkarni
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800,Australia.
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Wilce
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Melbourne 3800,Australia. Electronic address: mibel.aguilar@monash.edu.
authors.forename: Marie-Isabel
authors.initials: MI
authors.lastname: Aguilar
mesh_terms: D000595:Amino Acid Sequence; D019921:Biotinylation; D001718:Birefringence; D002352:Carrier Proteins / Q000494:pharmacology; D057846:Cell-Penetrating Peptides / Q000494:pharmacology*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D005782:Gels; D007368:Interferometry; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry; D008956:Models, Chemical; D010446:Peptide Fragments / Q000494:pharmacology; D010713:Phosphatidylcholines / Q000737:chemistry; D010715:Phosphatidylglycerols / Q000737:chemistry; D011485:Protein Binding; D013329:Structure-Activity Relationship
chemical_list: D002352:Carrier Proteins; D057846:Cell-Penetrating Peptides; D005782:Gels; D008051:Lipid Bilayers; D008081:Liposomes; D008563:Membrane Lipids; D010446:Peptide Fragments; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C414409:penetratin; C002773:dimyristoylphosphatidylglycerol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine
keywords: Birefringence; Cell penetrating peptide; Dual polarisation interferometry; Penetratin; Supported lipid bilayer