Co-existence of phases in twisted DNA
David Argudo (University of Pennsylvania), Prashant Purohit (University of Pennsylvania)
Mechanics of Phase Transforming and Multifunctional Materials
Tue 10:45 - 12:15
CIT 219
DNA is a helical rod-like molecule with an intrinsic right handed twist. We will refer to this right handed twist as positive. When DNA is twisted in the sense opposite to its intrinsic twist it can undergo phase transitions. Recently, a left-handed form of DNA, called L-DNA, has been discovered which is stable at high tensions and negative twist. Some effective properties of this new phase of DNA are known from experiments. In this talk we will examine the hypothesis that L-DNA is a mixture of two relatively well-characterized DNA phases - S-DNA and Z-DNA. Our primary tool of analysis is a heterogeneous fluctuating rod model for the studying the statistical mechanics of DNA. We will show that all the experimental data on L-DNA can be captured it we assume that it is a mixture of two phases. We will also use our model to study the mechanical properties of drug-DNA complexes which can also be modeled as phase mixtures.