Dna Denaturation-Supercoiling Transition at Thermophilic Temperatures
نویسندگان
چکیده
منابع مشابه
Nucleation at the DNA supercoiling transition.
Twisting DNA under a constant applied force reveals a thermally activated transition into a state with a supercoiled structure known as a plectoneme. Using transition-state theory, we predict the rate of this plectoneme nucleation to be of order 10(4) Hz. We reconcile this with experiments that have measured hopping rates of order 10 Hz by noting that the viscous drag on the bead used to manipu...
متن کاملDiscontinuities at the DNA supercoiling transition.
While slowly turning the ends of a single molecule of DNA at constant applied force, a discontinuity was recently observed at the supercoiling transition when a small plectoneme is suddenly formed. This can be understood as an abrupt transition into a state in which stretched and plectonemic DNA coexist. We argue that there should be discontinuities in both the extension and the torque at the t...
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In both eukaryotic and prokaryotic DNA sequences of 30–100 base-pairs rich in AT base-pairs have been identified at which the double helix preferentially unwinds. Such DNA unwinding elements are commonly associated with origins for DNA replication and transcription, and with chromosomal matrix attachment regions. Here we present a quantitative study of local DNA unwinding based on extensive sin...
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The topological state of DNA in hyperthermophilic archaea appears to correspond to a linking excess in comparison with DNA in mesophilic organisms. Since DNA binding proteins often contribute to the control of DNA topology by affecting DNA geometry in the presence of DNA topoisomerases, we tested whether the histone-like protein Sso7d from the hyperthermophilic archaeon Sulfolobus solfataricus ...
متن کاملSupplemental material for Discontinuities at the DNA supercoiling transition
Note that Ceff is a function of force: there is less “softening” at higher forces. In the experiments of Forth et al., the renormalized Ceff was measured directly via the torque. However, the range of applied forces was small enough that Ceff did not change appreciably, and a single value of C = (89 nm)kT was quoted. Here, we also use the same renormalized but force-independent value for C. Cha...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2014
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2013.11.3844