  We propose a nonlinear model derived from first principles, to describe
bubble dynamics of DNA. Our model equations include a term derived from the
dissipative effect of intermolecular vibrational modes. Such modes are excited
by the propagating bubble, and we term it "curvature dissipation". The
equations we derive allow for stable pinned localized kinks which form the
bubble. We perform the stability analysis and specify the energy requirements
for the motion of the localized solutions. Our findings are consistent with
properties of DNA dynamics, and can be used in models for denaturation bubbles,
RNA and DNA transcription, nucleotide excision repair and meiotic
recombination.
