Mechanical Cooperativity in DNA Cruciform Structures. Issue 20 (1st August 2018)

• Record Type: Journal Article
• Authors: Mandal, Shankar; Selvam, Sangeetha; Cui, Yunxi; Hoque, Mohammed Enamul; Mao, Hanbin
• Is Part Of: Chemphyschem. Volume 19:Issue 20(2018)
• Page Start: 2627
• Page End: 2634
• Publication Date: 2018-08-01
• Subjects: DNA cruciform -- magneto-optical tweezers -- mechanical cooperativity -- superhelicity -- torsionally constrained DNA; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201800480
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Unlike short‐range chemical bonds that maintain chemical properties of a biological molecule, long‐range mechanical interactions determine mechanochemical properties of molecules. Limited by experimental approaches, however, direct quantification of such mechanical interactions is challenging. Using magneto‐optical tweezers, herein we found torque can change the topology and mechanochemical property of DNA cruciform, a naturally occurring structure consisting of two opposing hairpin arms. Both mechanical and thermodynamic stabilities of DNA cruciforms increase with positive torque, which have been attributed to the topological coupling between DNA template and the cruciform. The coupling exists simultaneously in both arms of a cruciform, which coordinates the folding and unfolding of the cruciform, leading to a mechanical cooperativity not observed previously. As DNA torque readily varies during transcriptions, our finding suggests that DNA cruciforms can modulate transcriptions by adjusting their properties according to the torque. Abstract : Mechanical cooperativity : Using magneto‐optical tweezers, the authors studied the mechanochemical properties of a DNA cruciform. Both the mechanical and thermodynamic stabilities of DNA cruciforms increase with torque, which can be explained by topological coupling between the DNA template and the cruciform. This coupling exists simultaneously in both arms of a cruciform, which coordinates its folding and unfolding and leads to mechanical cooperativity.