title: Mechanical properties of DNA origami nanoassemblies are determined by Holliday junction mechanophores.
abstract: DNA nanoassemblies have demonstrated wide applications in various fields including nanomaterials, drug delivery and biosensing. In DNA origami, single-stranded DNA template is shaped into desired nanostructure by DNA staples that form Holliday junctions with the template. Limited by current methodologies, however, mechanical properties of DNA origami structures have not been adequately characterized, which hinders further applications of these materials. Using laser tweezers, here, we have described two mechanical properties of DNA nanoassemblies represented by DNA nanotubes, DNA nanopyramids and DNA nanotiles. First, mechanical stability of DNA origami structures is determined by the effective density of Holliday junctions along a particular stress direction. Second, mechanical isomerization observed between two conformations of DNA nanotubes at 10-35 pN has been ascribed to the collective actions of individual Holliday junctions, which are only possible in DNA origami with rotational symmetric arrangements of Holliday junctions, such as those in DNA nanotubes. Our results indicate that Holliday junctions control mechanical behaviors of DNA nanoassemblies. Therefore, they can be considered as 'mechanophores' that sustain mechanical properties of origami nanoassemblies. The mechanical properties observed here provide insights for designing better DNA nanostructures. In addition, the unprecedented mechanical isomerization process brings new strategies for the development of nano-sensors and actuators.
authors.affiliation: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
authors.forename: Prakash
authors.initials: P
authors.lastname: Shrestha
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Emura
authors.affiliation: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
authors.forename: Deepak
authors.initials: D
authors.lastname: Koirala
authors.affiliation: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
authors.forename: Yunxi
authors.initials: Y
authors.lastname: Cui
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Kumi
authors.initials: K
authors.lastname: Hidaka
authors.affiliation: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Maximuck
authors.affiliation: Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan endo@kuchem.kyoto-u.ac.jp.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Endo
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Yoshida-ushinomiyacho, Sakyo-ku, Kyoto 606-8501, Japan hs@kuchem.kyoto-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sugiyama
authors.affiliation: Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA hmao@kent.edu.
authors.forename: Hanbin
authors.initials: H
authors.lastname: Mao
mesh_terms: D055592:Biophysical Phenomena; D045566:DNA, Cruciform / Q000737:chemistry*; D007536:Isomerism; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry*; D043942:Nanotubes; D009690:Nucleic Acid Conformation
chemical_list: D045566:DNA, Cruciform