Adamcík Jozef, Víglaský Viktor, Valle Francesco, Antalík Marián, Podhradský Dusan, Dietler Giovanni
Department of Biochemistry, Faculty of Sciences, P. J. Sárik University, Kosice, Kosice, Slovakia.
Electrophoresis. 2002 Sep;23(19):3300-9. doi: 10.1002/1522-2683(200210)23:19<3300::AID-ELPS3300>3.0.CO;2-Q.
Changes in DNA supercoiling might be essential to generate the response of cellular machinery to temperature stress. The heat-induced structural transition for a topoisomer depends on the value of its specific linking difference. We detect only less negatively supercoiled DNA and an abundance of alternative irregular DNA forms at culture temperatures close to the growth limit of Escherichia coli. We show that the irregular forms are derived from regular plasmid DNAs and their population in the cells is temperature-dependent. Here, we show that it is possible to isolate and characterize individual DNA topoisomers directly from cells without a topoisomerase treatment. Temperature gradient gel electrophoresis (TGGE) and atomic force microscopy (AFM) were used to study the effect of bacteria growth temperature on the distribution of supercoiled DNA and its thermal stability.
DNA超螺旋的变化可能对于引发细胞机制对温度应激的反应至关重要。拓扑异构酶的热诱导结构转变取决于其特定连环差的值。在接近大肠杆菌生长极限的培养温度下，我们仅检测到负超螺旋程度较低的DNA以及大量其他不规则DNA形式。我们表明，这些不规则形式源自规则的质粒DNA，并且它们在细胞中的数量与温度有关。在这里，我们表明无需拓扑异构酶处理就可以直接从细胞中分离并表征单个DNA拓扑异构体。利用温度梯度凝胶电泳（TGGE）和原子力显微镜（AFM）研究细菌生长温度对超螺旋DNA分布及其热稳定性的影响。
