Opposite Effects of High-Valent Cations on the Elasticities of DNA and RNA Duplexes Revealed by Magnetic Tweezers

Hang Fu, Chen Zhang, Xiao-Wei Qiang, Ya-Jun Yang, Liang Dai, Zhi-Jie Tan, and Xing-Hua Zhang

Phys. Rev. Lett. 124, 058101 – Published 7 February 2020

Abstract

We report that trivalent cobalt hexammine cations decrease the persistence length, stretching modulus, helical density, and size of plectonemes formed under torque of DNA but increase those of RNA. Divalent magnesium cations, however, decrease the persistence lengths, contour lengths, and sizes of plectonemes while increasing the helical densities of both DNA and RNA. The experimental results are explained by different binding modes of the cations on DNA and RNA in our all-atom molecular dynamics simulations. The significant variations of the helical densities and structures of DNA and RNA duplexes induced by high-valent cations may affect interactions of the duplexes with proteins.

Received 8 May 2019
Accepted 16 January 2020

DOI:https://doi.org/10.1103/PhysRevLett.124.058101

Physics Subject Headings (PhySH)

Aggregation Biomechanics Biomolecular dynamics DNA-protein interactions RNA structure RNA-protein interactions

DNA RNA

Optical tweezers Single molecule techniques

Physics of Living SystemsPolymers & Soft Matter

Authors & Affiliations

Hang Fu^1,*, Chen Zhang^1,*, Xiao-Wei Qiang^2,*, Ya-Jun Yang¹, Liang Dai³, Zhi-Jie Tan^2,‡, and Xing-Hua Zhang ^1,†

¹College of Life Sciences, the Institute for Advanced Studies, State Key Laboratory of Virology, Hubei Key Laboratory of Cell Homeostasis, Wuhan University, Wuhan 430072, China
²Center for Theoretical Physics and Key Laboratory of Artificial Micro & Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
³Department of Physics, City University of Hong Kong, Hong Kong 999077, China

^*H. F., C. Z., and X.-W. Q. contributed equally to this work.
^†Corresponding author. zhxh@whu.edu.cn
^‡Corresponding author. zjtan@whu.edu.cn

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Issue

Vol. 124, Iss. 5 — 7 February 2020

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