LOW FREQUENCY MODES & THEIR ROLE IN EQUILIBRATION

振动跃迁对温度(频率)很敏感 移位和带宽变化)，因此建议开发瞬变 红外光谱方法研究蛋白质和其他结构中的热传输 水溶液。特别是，水的红外光谱是 通过加热破坏氢键而改变的，并建议 方法可以测量约0.02℃的变化。在最近的实验中， 由亚铁血红素的能量流动引起的温度变化 组为研究对象。中加热信号的上升时间 脱氧血红蛋白(Hb)和脱氧肌球蛋白(Mb)溶液在 详细研究血红素中的能量传输机制 蛋白质。这种传播率增加的动力学符合 一种由快和慢两部分组成的模型。禁食 分量最好用随时间变化的高斯上升函数来拟合 Mb溶液和Hb的常数分别为7.5 1 1.5和8.5 1 1.5 pS 解决方案分别为。慢速分量(约20ps)，40% 总振幅，归因于从血红素到 水通过蛋白质的经典扩散过程基于 测量的时间与经典计算的时间之间的一致性 扩散理论。快速组件，两种HB几乎相同 和Mb，不能用经典扩散理论描述，是 建议通过蛋白质的集体运动进行。 肌红蛋白(Mb)的实验也被用来研究 从血红素激发后的能量流向不同的电子 亚铁血红素的状态。独特的吸收和漂白特性可以 归因于松弛的Mb内振动“热”的血红素 时间常数为2~5ps。

Vibrational transitions are sensitive to temperature (frequency shifts and bandwidth changes) so it is proposed to develop transient IR methods to study heat transport in proteins and other structures in aqueous solutions. In particular, the IR spectrum of water is modified by heating which breaks hydrogen bonds and the proposed methods can measure changes of ca. 0.02 C. In recent experiments the changes in temperature arising from the flow of energy from a heme group was studied. The rise times of the heating signal in deoxyhemoglobin (Hb) and deoxymyoglobin (Mb) solutions were studied in detail to investigate the energy transport mechanisms in heme proteins. The kinetics of this increase of transmission is fitted to a model that consists of a fast and a slow component. The fast component is best fitted by a Gaussian rise function with time constants of 7.5 1 1.5 and 8.5 1 1.5 ps for Mb solution and Hb solutions, respectively. The slow component (ca. 20 ps), with 40% of the total amplitude, was attributed to energy transfer from heme to water through the protein via a classical diffusion process based on agreement between the measured time and that calculated with classical diffusion theory. The fast component, almost identical for both Hb and Mb, could not be described by classical diffusion theory and is suggested to proceed through collecti ve motions of the protein. Experiments on myoglobin (Mb) were also performed to investigate the flow of energy from heme after excitation into different electronic states of the heme. Distinct absorption and bleaching features could be ascribed to vibrationally "hot" heme within the Mb that relaxed with a time constant of 2 to 5 ps.