Physical properties of the E. coli 4.5S RNA: first results suggest a hairpin helix of unusual thermal stability.
Physical properties of the E. coli 4.5S RNA: first results suggest a hairpin helix of unusual thermal stability.
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大肠杆菌 4.5S RNA 的物理特性：第一个结果表明发夹螺旋具有不同寻常的热稳定性。
DOI：
10.1093/nar/12.4.2019
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发表时间：
1984
影响因子：
14.9
通讯作者：
Fournier,MJ
中科院分区：
文献类型：
--
作者：
Bourgaize,DB;Farrell,C;Langley,KH;Fournier,MJ
利用高显色性测量和准弹性激光散射（QELS）来评估代谢稳定的大肠杆菌4.5 s RNA的溶液结构。热变性测量结果表明，4.55种RNA比迄今为止表征的大多数其他RNA明显更稳定。光学Tm的范围为79°~ 88°，跃迁宽度为25°C。Tm值与离子强度的关系不大，但Mg+2显著提高了稳定性。在QELS实验中，扩散系数直到70°C才减小。扩散熔化和无限稀释时的扩散系数（）均与离子强度无关，但均受Mg+2的影响。对于长125 ~ 160 a，直径37 ~ 26 Å的刚性圆柱形分子，其扩散行为与预测一致。综上所述，这些结果与可以形成的更稳定的假设二级结构一致，其中114个碱基中的70-75%配对形成单个扩展的发夹螺旋。
Hyperchromicity measurements and quasi-elastic laser light scattering (QELS) have been used to assess the solution structure of the metabolically stableE.coli4.5S RNA Results from thermal denaturation measurements revealed the 4.55 species to be markedly more stable than most other RNAs characterized thus far. Optical Tm's range from 79° to 88° with transitions ˜25°C wide The Tm values show little dependence on ionic strength, but stability is enhanced considerably by Mg+2. In the QELS experiments the diffusion coefficient does not decrease until T > 70°C. Neither the diffusive melting nor the diffusion coefficient at infinite dilution () show dependencies on ionic strength but both are influenced by Mg+2. The diffusion behavior is in agreement with that predicted for a rigid cylindrical molecule 125 to 160 A long and 37 to 26 Å in diameter. Taken together these results are consistent with the more stable hypothetical secondary structures that can be formed, in which 70–75% of the 114 bases are paired to form a single extended hairpin helix.