离子强度对产黄青霉噬菌体双链RNA稳定性和构象的影响
Ionic strength effects on the stability and conformation of Penicillium chrysogenum mycophage double stranded RNA.
作者信息
Burnett J P, Frank B H, Douthart R J
出版信息
Nucleic Acids Res. 1975 Jun;2(6):759-71. doi: 10.1093/nar/2.6.759.
The effect of [Na+] on the stability and conformation of penicillium chrysogenum mycophage dsRNA (PCMdsRNA) was investigated using CD and UV optical techniques. Thermal melting profiles reveal prominent fine structure attributed to at least four regions of structural dissimilarity. A constant increased thermal stability of the dsRNA compared to DNA of the same base composition was observed over a concentration range of 1.5 times 10- minus 4 M to 4.5 times 10- minus 2 M Na+. At low ionic strengths ([Na+] less than 10- minus 3 M) Tm becomes independent of further decrease in [Na+] unless the dsRNA is exposed to high concentrations of EDTA, suggesting the involvement to tightly bound divalent cation. At relatively high ionic strengths ([Na+] greater than 0.1 M) a postulated A leads to A' ... conformation change occurs.
利用圆二色光谱（CD）和紫外光学技术研究了[Na⁺]对产黄青霉噬菌体双链RNA（PCMdsRNA）稳定性和构象的影响。热解链曲线显示出显著的精细结构，这归因于至少四个结构不同的区域。在1.5×10⁻⁴ M至4.5×10⁻² M的Na⁺浓度范围内，观察到与相同碱基组成的DNA相比，双链RNA的热稳定性持续增加。在低离子强度（[Na⁺]小于10⁻³ M）下，除非双链RNA暴露于高浓度的乙二胺四乙酸（EDTA），否则熔解温度（Tm）变得与[Na⁺]的进一步降低无关，这表明存在紧密结合的二价阳离子。在相对较高的离子强度（[Na⁺]大于0.1 M）下，推测会发生A到A'...的构象变化。
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