Dependence of Vibrational Energy Transfer on Distance in a Four-helix Bundle Protein: Equidistant Increments with the Periodicity of α Helices
Dependence of Vibrational Energy Transfer on Distance in a Four-helix Bundle Protein: Equidistant Increments with the Periodicity of α Helices
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四螺旋束蛋白中振动能量转移对距离的依赖性：随 α 螺旋周期性的等距增量
DOI：
10.1021/acs.jpcb.2c00956
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
and Yasuhisa Mizutani
中科院分区：
文献类型：
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作者：
Satoshi Yamashita,Misao Mizuno;Kazuhiro Takemura;Akio Kitao;and Yasuhisa Mizutani
不同自由度之间的振动能量交换是蛋白质跨越障碍过程的关键。血红素蛋白非常适合研究蛋白质中的振动能量交换。利用时间分辨反斯托克斯紫外共振拉曼光谱可以观察到血红素在蛋白质部分释放的过剩能量的迁移。色氨酸残基的反斯托克斯共振拉曼强度是一个很好的超额能量探针，可以实现单个氨基酸残基的空间分辨。在这里，我们研究了细胞色素b562的振动能量转移对距离的依赖关系，细胞色素b562是一种含有血红素的四螺旋束蛋白。以α螺旋为周期，用准恒定长度研究了不同血红素-色氨酸距离下，通过定点突变引入的从血红素基团到单个色氨酸残基的振动能量转移。结合分子动力学模拟得到的结构数据，能量传递可以用经典的热扩散模型很好地描述，这表明连续介质提供了一个很好的近似蛋白质内部的原子堆积密度。
Vibrational energy exchanges between various degrees of freedom are critical to barrier-crossing processes in proteins. Heme proteins are highly suitable for studies of the vibrational energy exchanges in proteins. The migration of excess energy released by heme in a protein moiety can be observed using time-resolved anti-Stokes ultraviolet resonance Raman spectroscopy. The anti-Stokes resonance Raman intensity of a tryptophan residue is an excellent probe for the excess energy and the spatial resolution of a single amino acid residue can be achieved. Here, we studied dependence of vibrational energy transfer on the distance in cytochromeb562, which is a heme-containing, four-helix bundle protein. The vibrational energy transfer from the heme group to a single tryptophan residue introduced by site-directed mutagenesis was examined for different heme-tryptophan distances by a quasi-constant length with the periodicity of α helices. Taken together with structural data obtained by molecular dynamics simulations, the energy transfer could be well described by the model of classical thermal diffusion, which suggests that continuum media provide a good approximation of the protein interior, of which the atomic packing density is very high.