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摘要
En 中文
Closing each strand of a DNA duplex upon itself fixes its linking number L. This topological condition couples together the secondary and tertiary structures of the resulting ccDNA topoisomer, a constraint that is not present in otherwise identical nicked or linear DNAs. Fixing L has a range of structural, energetic and functional consequences. Here we consider how L having different integer values (that is, different superhelicities) affects ccDNA molecules. The approaches used are primarily theoretical, and are developed from a historical perspective. In brief, processes that either relax or increase superhelicity, or repartition what is there, may either release or require free energy. The energies involved can be substantial, sufficient to influence many events, directly or indirectly. Here two examples are developed. The changes of unconstrained superhelicity that occur during nucleosome attachment and release are examined. And a simple theoretical model of superhelically driven DNA structural transitions is described that calculates equilibrium distributions for populations of identical topoisomers. This model is used to examine how these distributions change with superhelicity and other factors, and applied to analyze several situations of biological interest. Graphical Abstract
Keyword:
ALTERED SECONDARY STRUCTURE
HELIX-COIL TRANSITION
CLOSED CIRCULAR DNA
RNA-POLYMERASE-II
DUPLEX DESTABILIZATION
THEORETICAL-ANALYSIS
SUPERCOILED DNA
CONFORMATIONAL TRANSITIONS
INVERTED REPEAT
B-DNA
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期刊
IF:
13.1
论文数:
3.6W
被引数:
29.0W
机构
引用论文
Interplay between DNA sequence and negative superhelicity drives R-loop structuresDNA序列与负超螺旋之间的相互作用驱动R环结构
Mitotic stability of an episomal vector containing a human scaffold/matrix-attached region is provided by association with nuclear matrix
NATURE CELL BIOLOGY
IF19.1

