Dynamics of hemoglobin in human erythrocytes and in solution: influence of viscosity studied by ultrafast vibrational echo experiments.
Dynamics of hemoglobin in human erythrocytes and in solution: influence of viscosity studied by ultrafast vibrational echo experiments.
复制标题
人类红细胞和溶液中血红蛋白的动力学：通过超快振动回波实验研究粘度的影响。
DOI：
10.1021/ja0454790
复制
发表时间：
2004
影响因子：
15
通讯作者：
Fayer,MD
中科院分区：
文献类型：
--
作者：
McClain,BrianL;Finkelstein,IlyaJ;Fayer,MD
超快光谱分辨受激振动回波实验用于测量活体人类红细胞（红细胞）、液体溶液和玻璃基质中血红蛋白−CO（HbCO）的CO伸缩模式的振动失相。提出了一种克服细胞强光散射对振动回波信号影响的方法。将来自细胞质HbCO的结果与在不同缓冲液、含有低浓度和高浓度甘油的溶液以及固体海藻糖基质中制备的水性HbCO样品的实验进行比较。测量也提供了一个准确的测定粘度在非常高的Hb浓度，发现细胞内。它表明，由CO配体感测的蛋白质的动力学，是相同的红细胞内和水溶液中，是独立的粘度。在主要是甘油的溶液中，动力学略有改变，但仍然与粘度无关。在海藻糖中的实验给出了无限粘度下的动力学，并用于分离粘度依赖的动力学和粘度无关的动力学。虽然HbCO动力学是相同的红细胞和在等效的水溶液中，吸收光谱的差异表明，蛋白质的平衡substates的分布是敏感的小pH值的差异。
Ultrafast spectrally resolved stimulated vibrational echo experiments are used to measure the vibrational dephasing of the CO stretching mode of hemoglobin−CO (HbCO) inside living human erythrocytes (red blood cells), in liquid solutions, and in a glassy matrix. A method is presented to overcome the adverse impact on the vibrational echo signal from the strong light scattering caused by the cells. The results from the cytoplasmic HbCO are compared to experiments on aqueous HbCO samples prepared in different buffers, solutions containing low and high concentrations of glycerol, and in a solid trehalose matrix. Measurements are also presented that provide an accurate determination of the viscosity at the very high Hb concentration that is found inside the cells. It is demonstrated that the dynamics of the protein, as sensed by the CO ligand, are the same inside the erythrocytes and in aqueous solution and are independent of the viscosity. In solutions that are predominantly glycerol, the dynamics are modified somewhat but are still independent of viscosity. The experiments in trehalose give the dynamics at infinite viscosity and are used to separate the viscosity-dependent dynamics from the viscosity-independent dynamics. Although the HbCO dynamics are the same in the red blood cell and in the equivalent aqueous solutions, differences in the absorption spectra show that the distribution of a protein's equilibrium substates is sensitive to small pH differences.