HENRY M. SOBELL

INTRODUCTION

DNA premelting phenomena are spontaneous dynamical processes known to occur well below the melting temperature of DNA. They reflect DNA breathing, a process that combines the transient unstacking of base-pairs (i.e., to allow planar drugs and dyes to intercalate into DNA), with the transient breaking and rejoining of hydrogen-bonds connecting base-pairs in limited DNA regions (i.e., to allow tritium nuclei in hydrogen bonds connecting base-pairs to exchange with protons in water). The formation and propagation of chain-slippage structures either within or between homologous DNA molecules, along with a variety of structural phase transitions in DNA are also included in discussions of premelting phenomena.

This discussion describes how concepts of kink-antikink bound states (i.e., breather solitons) and their bifurcations have been used to assist in understanding a wide range of DNA premelting phenomena.