通过TGGE观察到超螺旋DNA拓扑异构体的早期解旋
Early melting of supercoiled DNA topoisomers observed by TGGE.
作者信息
Víglaský V, Antalík M, Adamcík J, Podhradský D
机构信息
P.J. Safarik University, Faculty of Sciences, Department of Biochemistry, Moyzesova 11, 041 54 Koice, Slovakia and Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 043 53 Koice, Slovakia.
出版信息
Nucleic Acids Res. 2000 Jun 1;28(11):E51. doi: 10.1093/nar/28.11.e51.
We have used temperature gradient gel electrophoresis (TGGE) to measure the progress of local denaturation in closed circular topoisomer DNA as a function of temperature and superhelicity (sigma). We describe the versatility of this method as a tool for detecting various conformational modifications of plasmid DNAs. The early melting temperature of a structural transition for any topoisomer is dependent on the value of superhelicity. Supercoiled topo-isomers represent a system of molecules that is sensitive to changes in temperature. We show that the topoisomer with the highest absolute value of superhelicity melts earlier than topoisomers with lower values. Thermal sensitivity of highly supercoiled plasmids could play a biologically important role in regulation of replication and expression in cells under thermal stress. The estimated melting temperature for plasmids with sigma < -0.05 is very significant because these temperatures for early melting are below physiological temperatures.
我们利用温度梯度凝胶电泳（TGGE）来测量闭环拓扑异构DNA中局部变性过程随温度和超螺旋度（σ）的变化情况。我们阐述了该方法作为检测质粒DNA各种构象修饰工具的多功能性。任何拓扑异构体结构转变的早期解链温度取决于超螺旋度的值。超螺旋拓扑异构体代表了一个对温度变化敏感的分子系统。我们发现，超螺旋度绝对值最高的拓扑异构体比超螺旋度较低的拓扑异构体更早解链。高度超螺旋质粒的热敏感性在热应激条件下细胞的复制和表达调控中可能发挥重要的生物学作用。对于σ < -0.05的质粒，估计的解链温度非常重要，因为这些早期解链温度低于生理温度。
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