Tehei Moeava, Franzetti Bruno, Madern Dominique, Ginzburg Margaret, Ginzburg Ben Z, Giudici-Orticoni Marie-Thérèse, Bruschi Mireille, Zaccai Giuseppe
Institut de Biologie Structurale, CEA-CNRS-UJF, IBS, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France.
EMBO Rep. 2004 Jan;5(1):66-70. doi: 10.1038/sj.embor.7400049.
Mean macromolecular dynamics was quantified in vivo by neutron scattering in psychrophile, mesophile, thermophile and hyperthermophile bacteria. Root mean square atomic fluctuation amplitudes determining macromolecular flexibility were found to be similar for each organism at its physiological temperature ( approximately 1 A in the 0.1 ns timescale). Effective force constants determining the mean macromolecular resilience were found to increase with physiological temperature from 0.2 N/m for the psychrophiles, which grow at 4 degrees C, to 0.6 N/m for the hyperthermophiles (85 degrees C), indicating that the increase in stabilization free energy is dominated by enthalpic rather than entropic terms. Larger resilience allows macromolecular stability at high temperatures, while maintaining flexibility within acceptable limits for biological activity.
通过中子散射对嗜冷菌、嗜温菌、嗜热菌和超嗜热菌进行体内研究，定量分析了平均大分子动力学。结果发现，在各生物体的生理温度下（在0.1纳秒时间尺度上约为1埃），决定大分子柔韧性的均方根原子波动幅度相似。决定平均大分子弹性的有效力常数随生理温度升高而增加，从生长在4℃的嗜冷菌的0.2N/m，增加到超嗜热菌（85℃）的0.6N/m，这表明稳定自由能的增加主要由焓项而非熵项主导。更大的弹性使得大分子在高温下保持稳定，同时在生物活性可接受的范围内保持柔韧性。
