Dynamics of proteins encapsulated in silica sol-gel glasses studied with IR vibrational echo spectroscopy.
Dynamics of proteins encapsulated in silica sol-gel glasses studied with IR vibrational echo spectroscopy.
复制标题
用红外振动回波光谱研究封装在硅溶胶-凝胶玻璃中的蛋白质的动力学。
DOI：
10.1021/ja058745y
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发表时间：
2006
影响因子：
15
通讯作者：
Fayer,MichaelD
中科院分区：
文献类型：
--
作者：
Massari,AaronM;Finkelstein,IlyaJ;Fayer,MichaelD
光谱分辨红外刺激振动回波光谱用于测量嵌入硅溶胶凝胶玻璃中的碳单氧肌红蛋白 (MbCO) 和β-血红蛋白 (HbCO) 中与血红素结合的 CO 的快速动力学。在 ~100 fs 到几皮秒的时间尺度上，与蛋白质水溶液相比，MbCO 和 HbCO 与血红素结合的 CO 的振动相移明显较慢。由血红素结合的 CO 感知到的 MbCO 的快速结构动力学比 HbCO 更受溶胶凝胶环境的影响。与水溶液中封装在溶胶凝胶玻璃中的两种蛋白质相比，通过光谱扩散程度测量的较长时间尺度的结构动力学（数十皮秒）是相同的。将溶胶凝胶实验结果与对水和果糖的各种混合物采集的粘度依赖性振动回波数据进行比较表明，溶胶凝胶封装的 MbCO 表现出的动力学相当于溶液中的蛋白质，该溶液的粘度比散装水高近 20 倍。相比之下，溶胶凝胶中的 HbCO 相移仅反映粘度增加了 2 倍。通过改变用于制备溶胶-凝胶玻璃的硅烷前体与水的摩尔比（R值）来改变封装孔径的尝试被发现对快速或稳态光谱结果没有影响。在溶剂限制和蛋白质-孔壁相互作用的背景下讨论振动回波数据，以深入了解限制环境对生物分子经历的快速结构动力学的影响。
Spectrally resolved infrared stimulated vibrational echo spectroscopy is used to measure the fast dynamics of heme-bound CO in carbonmonoxy-myoglobin (MbCO) and -hemoglobin (HbCO) embedded in silica sol−gel glasses. On the time scale of ∼100 fs to several picoseconds, the vibrational dephasing of the heme-bound CO is measurably slower for both MbCO and HbCO relative to that of aqueous protein solutions. The fast structural dynamics of MbCO, as sensed by the heme-bound CO, are influenced more by the sol−gel environment than those of HbCO. Longer time scale structural dynamics (tens of picoseconds), as measured by the extent of spectral diffusion, are the same for both proteins encapsulated in sol−gel glasses compared to that in aqueous solutions. A comparison of the sol−gel experimental results to viscosity-dependent vibrational echo data taken on various mixtures of water and fructose shows that the sol−gel-encapsulated MbCO exhibits dynamics that are the equivalent of the protein in a solution that is nearly 20 times more viscous than bulk water. In contrast, the HbCO dephasing in the sol−gel reflects only a 2-fold increase in viscosity. Attempts to alter the encapsulating pore size by varying the molar ratio of silane precursor to water (Rvalue) used to prepare the sol−gel glasses were found to have no effect on the fast or steady-state spectroscopic results. The vibrational echo data are discussed in the context of solvent confinement and protein−pore wall interactions to provide insights into the influence of a confined environment on the fast structural dynamics experienced by a biomolecule.