title: Intermediate phase in DNA melting.
abstract: We predict a temperature-driven phase transition of DNA below the melting transition. The additional, intermediate phase exists for repetitive sequences, when the two strands have different lengths. In this phase, the excess bases of the longer strand are completely absorbed as bulge loops inside the helical region. When the temperature is lowered, the excess bases desorb into overhanging ends, resulting in a contour length change. This continuous transition is in many aspects analogous to Bose-Einstein condensation. When the sequence is weakly disordered, the contour length changes discontinuously with temperature.
authors.affiliation: Arnold-Sommerfeld-Center for Theoretical Physics and Center for NanoScience, LMU München, Theresienstrasse 37, 80333 München, Germany. richard.neher@physik.lmu.de
authors.forename: Richard A
authors.initials: RA
authors.lastname: Neher
authors.forename: Ulrich
authors.initials: U
authors.lastname: Gerland
mesh_terms: D001483:Base Sequence; D003198:Computer Simulation; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D044367:Phase Transition; D017422:Sequence Analysis, DNA / Q000379:methods*; D013329:Structure-Activity Relationship; D013696:Temperature; D044366:Transition Temperature
chemical_list: D004247:DNA