title: Folding Topology of a Short Coiled-Coil Peptide Structure Templated by an Oligonucleotide Triplex.
abstract: The rational design of a well-defined protein-like tertiary structure formed by small peptide building blocks is still a formidable challenge. By using peptide-oligonucleotide conjugates (POC) as building blocks, we present the self-assembly of miniature coiled-coil α-helical peptides guided by oligonucleotide duplex and triplex formation. POC synthesis was achieved by copper-free alkyne-azide cycloaddition between three oligonucleotides and a 23-mer peptide, which by itself exhibited multiple oligomeric states in solution. The oligonucleotide domain was designed to furnish a stable parallel triplex under physiological pH, and to be capable of templating the three peptide sequences to constitute a small coiled-coil motif displaying remarkable α-helicity. The formed trimeric complex was characterized by ultraviolet thermal denaturation, gel electrophoresis, circular dichroism (CD) spectroscopy, small-angle X-ray scattering (SAXS), and molecular modeling. Stabilizing cooperativity was observed between the trimeric peptide and the oligonucleotide triplex domains, and the overall molecular size (ca. 12 nm) in solution was revealed to be independent of concentration. The topological folding of the peptide moiety differed strongly from those of the individual POC strands and the unconjugated peptide, exclusively adopting the designed triple helical structure.
authors.affiliation: Biomolecular Nanoscale Engineering Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
authors.forename: Chenguang
authors.identifier: http://orcid.org/0000-0002-9521-8285
authors.initials: C
authors.lastname: Lou
authors.affiliation: Biomolecular Nanoscale Engineering Center, Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
authors.forename: Niels Johan
authors.identifier: http://orcid.org/0000-0001-9588-2656
authors.initials: NJ
authors.lastname: Christensen
authors.affiliation: Biomolecular Nanoscale Engineering Center, Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
authors.forename: Manuel C
authors.identifier: http://orcid.org/0000-0002-4952-4329
authors.initials: MC
authors.lastname: Martos-Maldonado
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
authors.forename: Søren Roi
authors.identifier: http://orcid.org/0000-0001-6694-0626
authors.initials: SR
authors.lastname: Midtgaard
authors.affiliation: Biomolecular Nanoscale Engineering Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: Ejlersen
authors.affiliation: Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100, Copenhagen Ø, Denmark.
authors.forename: Peter W
authors.identifier: http://orcid.org/0000-0002-9241-4352
authors.initials: PW
authors.lastname: Thulstrup
authors.affiliation: Biomolecular Nanoscale Engineering Center, Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
authors.forename: Kasper K
authors.initials: KK
authors.lastname: Sørensen
authors.affiliation: Biomolecular Nanoscale Engineering Center, Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark.
authors.forename: Knud J
authors.identifier: http://orcid.org/0000-0003-3525-5452
authors.initials: KJ
authors.lastname: Jensen
authors.affiliation: Biomolecular Nanoscale Engineering Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
authors.forename: Jesper
authors.identifier: http://orcid.org/0000-0001-9835-1009
authors.initials: J
authors.lastname: Wengel
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002384:Catalysis; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry; D061565:Cycloaddition Reaction; D004591:Electrophoresis, Polyacrylamide Gel; D009693:Nucleic Acid Hybridization; D009841:Oligonucleotides / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D009841:Oligonucleotides; D010455:Peptides; D003300:Copper
keywords: circular dichroism; click chemistry; molecular modeling; oligonucleotides; peptides