Unexpected Discontinuous Supercoiling of Torsionally Buckled DNA: Evidence for a Solenoid?
نویسندگان
چکیده
منابع مشابه
DNA supercoiling inhibits DNA knotting
Despite the fact that in living cells DNA molecules are long and highly crowded, they are rarely knotted. DNA knotting interferes with the normal functioning of the DNA and, therefore, molecular mechanisms evolved that maintain the knotting and catenation level below that which would be achieved if the DNA segments could pass randomly through each other. Biochemical experiments with torsionally...
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Type II DNA topoisomerases permit passages of double stranded DNA segments through each other and this is achieved via a complex mechanism involving a transient cleavage of one duplex, a passage of the second duplex through the topoisomerase-spanned cleavage site and finally resealing of the cut duplex. Type II DNA topoisomerases facilitate many DNA transactions requiring manipulation of long D...
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We present a method of detecting sequence defects by supercoiling DNA with magnetic tweezers. The method is sensitive to a single mismatched base pair in a DNA sequence of several thousand base pairs. We systematically compare DNA molecules with 0 to 16 adjacent mismatches at 1 M monovalent salt and 3.6 pN force and show that under these conditions, a single plectoneme forms and is stably pinne...
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Frequently, DNA in vivo is organized into loops that are partially underwound and consequently form interwound helical supercoils. Methods from polymer statistical mechanics are used to show how the competition between entropy (thermal fluctuations) and elastic energy determines supercoil radius and pitch, in good agreement with recent experiments and simulations. Supercoil reorganization by me...
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Supercoiling is a fundamental property of DNA and chromatin. It is modulated by polymerase and topoisomerase activities and, through regulated constraint, by DNA/chromatin binding proteins. As a non-covalent and elusive topological modification, supercoiling has proved intractable to research despite being a crucial regulator of nuclear structure and function. Recent studies have improved our u...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 2018
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2017.11.514