The Dynamics of Unfolded Versus Folded tRNA: The Role of Electrostatic Interactions

Published

September 21, 2011

Author(s)

Joon Ho Roh, Madhu Sudan Tyagi, Robert M. Briber, Sarah A. Woodson, Alexei P. Sokolov

Abstract

We have used quasielastic neutron scattering spectroscopy to study the dynamics of unfolded tRNA under low ionic strength and tRNA folded through the addition of Mg²⁺ in order to examine the role of electrostatic interactions in the dynamics of biological polyelectrolytes. Analyses of the atomic mean-squared displacement, relaxation time, molecular persistency, and mobile fraction showed that unfolded tRNA is dynamically more rigid due to intrinsic electrostatic repulsion than Mg²⁺ folded tRNA. This same result is found for a sulfonated polystyrene, a synthetic polyelectrolyte, where the system is dynamically more rigid in the unscreened state compared to the counterion screened state. These results are contrary the relationship between structural compactness and internal dynamics for proteins where the folded state is observed to be more rigid than denatured state. This implies that the dynamics of biological polyelectrolytes are strongly influenced by electrostatic environments rather than solely controlled by the dynamics of the local water.

Citation

Journal of American Chemical Society

Volume

133

Pub Type

Journals

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Keywords

Dynamics, t-RNA, protein, quasi-elastic neutron scattering

Citation

Roh, J. , Tyagi, M. , Briber, R. , Woodson, S. and Sokolov, A. (2011), The Dynamics of Unfolded Versus Folded tRNA: The Role of Electrostatic Interactions, Journal of American Chemical Society, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=909085 (Accessed April 26, 2024)