Linear <i>ds</i>DNA Partitions Spontaneously into the Inverse Hexagonal Lyotropic Liquid Crystalline Phases of Phospholipids

Recently, we reported that DNA associated with inverse hexagonal (H_II) lyotropic liquid crystal phases of the lipid 1,2-dioleoyl-<i>sn</i>-glycero-3-phosphoethanolamine (DOPE) was actively transcribed by T7 RNA polymerase. Our findings suggested that key components of the transcription process, probably the T7 RNA polymerase and the DNA, remained associated with the monolithic H_II phase throughout transcription. Here, we investigate the partitioning of DNA between an H_II lyotropic liquid crystal phase and an isotropic supernatant phase in order to develop insights into the localization of DNA in liquid crystalline environments. Our results show that linear double stranded DNA (<i>ds</i>DNA) molecules partition spontaneously into monolithic preformed H_II liquid crystal phases of DOPE. We propose that this process is driven by the increase in entropy due to the release of counterions from the DNA when it inserts into the aqueous pores of the H_II phase