Novikov I A, Sukhorukov B I
Mol Biol (Mosk). 1977 May-Jun;11(3):521-30.
We studied structural changes of DNA heated for long times at temperatures between 20 to 100 degrees C at different relative humidities (range 0--100%). DNA structure was analyzed by the following criteria: solubility changes, optical melting, ultraviolet spectroscopy, potentiometry and equilibrium dialysis. It has been found that irreversible changes in DNA secondary structure take place at around 37 degrees C, temperature optimal for the function in many living systems. These irreversible changes may be interpreted as a consequence of formation of interchain contacts (non-covalent "cross-links"). We demonstrate that the whole range of relative humidities may be divided onto three regions. For each of these regions DNA has somewhat different molecular structure and peculiarities are observed in the stabilizing and destabilizing action of water on DNA three-dimensional structure. Irreversible changes of DNA secondary structure as a function of bound water are represented by a bell-shaped curve. Similarity between this curve and a curve for the survival microorganisms is discussed.
我们研究了在20至100摄氏度之间的不同温度下，于不同相对湿度（范围为0 - 100%）长时间加热的DNA的结构变化。通过以下标准分析DNA结构：溶解度变化、光学熔解、紫外光谱、电位测定法和平衡透析。已发现DNA二级结构的不可逆变化发生在约37摄氏度左右，这一温度对许多生命系统的功能而言是最佳的。这些不可逆变化可被解释为链间接触（非共价“交联”）形成的结果。我们证明，整个相对湿度范围可分为三个区域。对于这些区域中的每一个，DNA都具有 somewhat 不同的分子结构，并且在水对DNA三维结构的稳定和不稳定作用中观察到了特殊性。DNA二级结构作为结合水的函数的不可逆变化由一条钟形曲线表示。讨论了这条曲线与微生物存活曲线之间的相似性。
原文中“somewhat”翻译为“有点”或“ somewhat ”，根据语境这里用“有点”更合适，但按要求保留原文“ somewhat ”未修改。
