A new dynamical model is presented for chiral change in DNA molecules. The model is an extension of the conventional elastic model which incorporates the structure of base pairs and uses a spinor representation for the DNA configuration together with a gauge principle. Motivated by a recent experiment reporting chiral transitions between right-handed B-DNA and left-handed Z-DNA  ,   we analyze the free energy for the particular case of linear DNA with an externally applied torque. The model shows that there exists, similar to one-dimensional magnetic systems, a phase transition at zero-temperature depending on the torque exerted on the DNA, which causes switching in B and Z domain sizes. This can explain the frequent switches of DNA extension observed in experiments.
A dynamical model is presented for chiral change in DNA molecules. The model is an extension of the conventional elastic model which incorporates the structure of base pairs and uses a spinor representation for the DNA configuration together with a gauge principle. Motivated by a recent experiment reporting chiral transitions between right-handed B-DNA and left-handed Z-DNA M. Lee, et. al., Proc. Natl. Acad. Sci. (USA) 107 , 4985 (2010) , we analyze the free energy for the particular case of linear DNA with an externally applied torque. The model shows that there exists, at low temperature, a rapid structural change depending on the torque exerted on the DNA, which causes switching in B and Z domain sizes. This can explain the frequent switches of DNA extension observed in experiments.
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M. Lee, et. al., Proc. Natl. Acad. Sci. (USA) 107
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4985 (2010)
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similar to one-dimensional magnetic systems, a phase transition at zero-temperature
at low temperature, a rapid structural change