title: Noncovalent triblock copolymers based on a coiled-coil peptide motif.
abstract: The formation of a noncovalent triblock copolymer based on a coiled-coil peptide motif is demonstrated in solution. A specific peptide pair (E and K) able to assemble into heterocoiled coils was chosen as the middle block of the polymer and conjugated to poly(ethylene glycol) (PEG) and polystyrene (PS) as the outer blocks. Mixing equimolar amounts of the polymer-peptide block copolymers PS-E and K-PEG resulted in the formation of coiled-coil complexes between the peptides and subsequently in the formation of the amphiphilic triblock copolymer PS-E/K-PEG. Aqueous self-assembly of the separate peptides (E and K), the block copolymers (PS-E and K-PEG), and equimolar mixtures thereof was studied by circular dichroism, dynamic light scattering, and cryogenic transmission electron microscopy. It was found that the noncovalent PS-E/K-PEG copolymer assembled into rodlike micelles, while in all other cases, spherical micelles were observed. Temperature-dependent studies revealed the reversible nature of the coiled-coil complex and the influence of this on the morphology of the aggregate. A possible mechanism for these transitions based on the interfacial free energy and the free energy of the hydrophobic blocks is discussed. The self-assembly of the polymer-peptide conjugates is compared to that of polystyrene-b-poly(ethylene glycol), emphasizing the importance of the coiled-coil peptide block in determining micellar structure and dynamic behavior.
authors.affiliation: Department of Soft Matter Chemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: Hana Robson
authors.initials: HR
authors.lastname: Marsden
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Korobko
authors.forename: Ellen N M
authors.initials: EN
authors.lastname: van Leeuwen
authors.forename: Emilie M
authors.initials: EM
authors.lastname: Pouget
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Veen
authors.forename: Nico A J M
authors.initials: NA
authors.lastname: Sommerdijk
authors.forename: Alexander
authors.initials: A
authors.lastname: Kros
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D002942:Circular Dichroism; D008027:Light; D008823:Micelles; D008958:Models, Molecular; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D012542:Scattering, Radiation; D013696:Temperature
chemical_list: D008823:Micelles; D010455:Peptides; D011137:Polystyrenes; D011092:Polyethylene Glycols