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Mechanical Cooperativity in DNA Cruciform Structures
Author(s) -
Mandal Shankar,
Selvam Sangeetha,
Cui Yunxi,
Hoque Mohammed Enamul,
Mao Hanbin
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201800480
Subject(s) - cruciform , cooperativity , dna , magnetic tweezers , chemical physics , chemistry , molecule , folding (dsp implementation) , holliday junction , biophysics , dna supercoil , optical tweezers , topology (electrical circuits) , nanotechnology , crystallography , materials science , physics , homologous recombination , biology , biochemistry , composite material , dna replication , optics , organic chemistry , mathematics , combinatorics , electrical engineering , engineering
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.