title: Structural behaviour and gene delivery in complexes formed between DNA and arginine-containing peptide amphiphiles.
abstract: We describe in depth the structure of complexes formed between DNA and two classes of arginine-containing peptide amphiphiles, namely, the lipopeptide PRW-C16(P = proline, R = arginine, W = tryptophan, C16= C16 : 0 alkyl chain) and the bolaamphiphile RFL4FR (R = arginine, F = phenylalanine, L = leucine). A combination of X-ray and neutron scattering provided unprecedented insights into the local structure of these complexes. Lipopeptide-based complexes self-assembled into layered structures with large-scale fractal features, hosting DNA in the interstices. Bola-amphiphile scaffolds were characterized by planar structures with DNA strands presumably sandwiched in-between peptide nanotapes. Importantly, complexation did not affect the structural integrity of DNA in either of the two complexes. The bolaamphiphile conjugates displayed high levels of molecular ordering in contrast to the liquid-crystalline features observed in lipopeptide assemblies. Peptide-DNA complexes were assessed for their potential as a means to deliver the reporter vector pEGFP-N1 into SW480 human colon carcinoma cells. Successfully transfected cells expressed green fluorescent protein. The potentiating effect of PRW-C16on the cellular uptake of ectopic DNA was found to be much greater than that observed with RFL4FR. In contrast to the bolaamphiphile-based conjugate, the liquid-crystalline nature of the lipopeptide complex is likely to play a key role in DNA release and transfection efficiency since these weakly bound structures require lower energy expenditure during disassembly and load release.
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André-SP, 09210-580, Brazil. ersilva@fis.ufal.br and Instituto de Física, Universidade Federal de Alagoas, Maceió-AL, 57072-900, Brazil.
authors.forename: Emerson R
authors.initials: ER
authors.lastname: Silva
authors.affiliation: School of Biotechnology and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
authors.forename: Gary
authors.initials: G
authors.lastname: Cooney
authors.affiliation: Department of Chemistry, University of Reading, Whiteknights, RG6 6AD, UK.
authors.forename: Ian W
authors.initials: IW
authors.lastname: Hamley
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André-SP, 09210-580, Brazil. ersilva@fis.ufal.br.
authors.forename: Wendel A
authors.initials: WA
authors.lastname: Alves
authors.affiliation: School of Biotechnology and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
authors.forename: Shannon
authors.initials: S
authors.lastname: Lee
authors.affiliation: School of Biotechnology and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
authors.forename: Brendan F
authors.initials: BF
authors.lastname: O'Connor
authors.affiliation: Department of Applied Physics, Aalto University School of Science, P. O. Box 15100, FI-00076, Finland.
authors.forename: Mehedi
authors.initials: M
authors.lastname: Reza
authors.affiliation: Department of Applied Physics, Aalto University School of Science, P. O. Box 15100, FI-00076, Finland.
authors.forename: Janne
authors.initials: J
authors.lastname: Ruokolainen
authors.affiliation: School of Biotechnology and National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland.
authors.forename: Dermot
authors.initials: D
authors.lastname: Walls
mesh_terms: D001120:Arginine / Q000737:chemistry*; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry*; D005822:Genetic Vectors / Q000737:chemistry*; D049452:Green Fluorescent Proteins; D006801:Humans; D010455:Peptides / Q000737:chemistry*; D014162:Transfection
chemical_list: D010455:Peptides; D049452:Green Fluorescent Proteins; D004247:DNA; D001120:Arginine