Dipartimento di Fisica, Università degli Studi di Perugia, Perugia, Italy.
J Phys Chem B. 2012 Mar 29;116(12):3861-5. doi: 10.1021/jp211190q. Epub 2012 Mar 9.
The coherent density fluctuations of a perdeuterated dry protein have been studied by Brillouin neutron spectroscopy. Besides a nearly wavevector-independent branch located around 5 meV, a propagating mode with a linear trend at low wavevector Q is revealed. The corresponding speed of 3780 ± 130 m/s is definitely higher than that of hydrated proteins. Above Q = 0.8 Å(-1), this mode becomes overdamped, with lifetimes shorter than 0.1 ps, in fashion similar to glassy materials. The present results indicate that dry proteins sustain coherent density fluctuations in the THz frequency regime. The trend of the longitudinal modulus indicates that in this frequency range dry biomolecules are more rigid than hydrated proteins.
利用布里渊中子散射技术研究了氘代干燥蛋白质的相干密度涨落。除了在大约 5meV 处的几乎与波矢无关的支外，还揭示了在低波矢 Q 处具有线性趋势的传播模。相应的速度为 3780±130m/s，明显高于水合蛋白质的速度。在 Q>0.8Å^(-1)处，该模变得过阻尼，寿命短于 0.1ps，类似于玻璃材料。目前的结果表明，干燥蛋白质在太赫兹频率范围内维持相干密度涨落。纵向模量的趋势表明，在该频率范围内，干燥生物分子比水合蛋白质更硬。
