Localization of Denaturation Bubbles in Random DNA Sequences

摘要

We study the thermodynamic and dynamic behaviors of twist-induceddenaturation bubbles in a long, stretched random sequence of DNA. The smallbubbles associated with weak twist are delocalized. Above a threshold torque,the bubbles of several tens of bases or larger become preferentially localizedto \AT-rich segments. In the localized regime, the bubbles exhibit ``aging''and move around sub-diffusively with continuously varying dynamic exponents.These properties are derived using results of large-deviation theory togetherwith scaling arguments, and are verified by Monte-Carlo simulations.