Direct measurement of the forces between complementary strands of DNA.
Interaction forces between single strands of DNA were measured with the atomic force microscope by a procedure in which DNA oligonucleotides were covalently attached to a spherical probe and surface. Adhesive forces measured between complementary 20-base strands fell into three distinct distributions centered at 1.52, 1.11, and 0.83 nano-newtons, which are associated with the rupture of the interchain interaction between a single pair of molecules involving 20, 16, and 12 base pairs, respectively. When a third long DNA molecule was coupled between complementary surfaces, both intra- and interchain forces were observed. The intrachain interaction resulting from the molecule's elasticity manifested itself as a long-range cohesive force.
Lee
G U
GU
Chemistry Division, Naval Research Laboratory, Washington, DC 20375.
Chrisey
L A
LA
Colton
R J
RJ
D001482:Base Composition; D001483:Base Sequence; D018076:DNA, Complementary / Q000737:chemistry*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013696:Temperature
D018076:DNA, Complementary; D004277:DNA, Single-Stranded; D009838:Oligodeoxyribonucleotides