title: C-5 Propynyl Modifications Enhance the Mechanical Stability of DNA.
abstract: Increased thermal or mechanical stability of DNA duplexes is desired for many applications in nanotechnology or -medicine where DNA is used as a programmable building block. Modifications of pyrimidine bases are known to enhance thermal stability and have the advantage of standard base-pairing and easy integration during chemical DNA synthesis. Through single-molecule force spectroscopy experiments with atomic force microscopy and the molecular force assay we investigated the effect of pyrimidines harboring C-5 propynyl modifications on the mechanical stability of double-stranded DNA. Utilizing these complementary techniques, we show that propynyl bases significantly increase the mechanical stability if the DNA is annealed at high temperature. In contrast, modified DNA complexes formed at room temperature and short incubation times display the same stability as non-modified DNA duplexes.
authors.affiliation: Center for Nanoscience and Department of Physics, University of Munich, Amalienstrasse 54, 80799 München (Germany).
authors.forename: Daniela
authors.initials: D
authors.lastname: Aschenbrenner
authors.affiliation: Center for Nanoscience and Department of Physics, University of Munich, Amalienstrasse 54, 80799 München (Germany).
authors.forename: Fabian
authors.initials: F
authors.lastname: Baumann
authors.affiliation: Center for Nanoscience and Department of Physics, University of Munich, Amalienstrasse 54, 80799 München (Germany).
authors.forename: Lukas F
authors.initials: LF
authors.lastname: Milles
authors.affiliation: Center for Nanoscience and Department of Physics, University of Munich, Amalienstrasse 54, 80799 München (Germany). diana.pippig@physik.uni-muenchen.de.|Munich Center for Integrated Protein Science (CIPSM), Butenandtstr. 5-13, 81377 München (Germany). diana.pippig@physik.uni-muenchen.de.
authors.forename: Diana A
authors.initials: DA
authors.lastname: Pippig
authors.affiliation: Center for Nanoscience and Department of Physics, University of Munich, Amalienstrasse 54, 80799 München (Germany).
authors.forename: Hermann E
authors.initials: HE
authors.lastname: Gaub
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000138:chemical synthesis / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D011743:Pyrimidines / Q000737:chemistry*; D013696:Temperature
chemical_list: D011743:Pyrimidines; D004247:DNA
keywords: biophysics; dna mechanical stability; force spectroscopy; propynyl bases; single-molecule studies