Regensburg 2004 – wissenschaftliches Programm
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SYLS: Life Sciences on the Nanometer Scale - Physics Meets Biology
SYLS 3: Symposium "Life Sciences on the Nanometer Scale - Physics Meets Biology"
SYLS 3.5: Poster
Mittwoch, 10. März 2004, 16:00–18:30, B
Interactions of biopolymers of fixed topology with thermal fluctuations — •Ralf Metzler1 and Andreas Hanke2 — 1NORDITA, Blegdamsvej 17, DK-2100 Copenhagen OE — 2Theoretical Physics, University of Oxford, Oxford OX1 3NP, United Kingdom
DNA knots of different complexity effect different mobility of the chain, and they pose an intricate problem to a biological cell in respect to transcription or replication. Specific enzymes remove knots very efficiently despite having access to local information, only. I will discuss ideas on how interaction of thermal fluctuations with the fixed topology of the chain may assist the enzymes in their task, and under which conditions this may actually work in vivo.
Double-stranded DNA even at physiological temperatures undergoes fluctuations, during which single-stranded bubbles open up along the strand. Increasing the temperature, dsDNA eventually undergoes a melting transition. Starting from a microscopic model for the Free energy, we derive a Fokker-Planck equation to the bubble fluctuations, whose predictions close to physiological temperatures reproduce recent experimental results on single bubble fluctuations.
References: R. Metzler, A. Hanke, P. G. Dommersnes, Y. Kantor, and M. Kardar, Phys. Rev. Lett. 88 (2002) 188101; Phys. Rev. E 65 (2002) 061103. A. Hanke and R. Metzler, Phys. Rev. Lett. 90 (2003) 159801, A. Hanke and R. Metzler, J. Phys. A (Lett.) 36 (2003) L473.