Nonbonded Atomic Contacts Drive Ultrafast Helix Motions in Myoglobin
Nonbonded Atomic Contacts Drive Ultrafast Helix Motions in Myoglobin
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非键合原子接触驱动肌红蛋白中的超快螺旋运动
DOI：
10.1021/acs.jpcb.0c04772
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发表时间：
2020
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：
Shinya Tahara;Misao Mizuno;and Yasuhisa Mizutani
小配体的缔合和解离通过蛋白质的结构变化来调节蛋白质的功能。这种结构变化传播很长的距离，这种变构在分子功能中起着关键作用。然而，结构变化的传递机制却知之甚少。在这里，我们表明，非键合的原子接触中起着至关重要的作用，在驱动位移的螺旋在皮秒时间尺度的主要结构变化后，一氧化碳的血红素组肌红蛋白的解离。目前的时间分辨紫外共振拉曼的研究表明，这种螺旋位移的幅度降低后取代Val68，它接触的血红素在野生型肌红蛋白，与体积较小的侧链（Ala）。我们的研究结果提供了第一个直接的证据表明，结构的变化不仅通过共价键，盐桥和氢键，但也通过非键合原子接触在配体解离后的主要蛋白质反应。此外，本研究结果表明，在蛋白质结构中的致密原子包装的重要性，以响应小分子的缔合和解离。蛋白质结构的高度紧密性使得结构变化的传播成为可能，为分子机器的设计提供了有用的线索。
The association and dissociation of small ligands regulate the functions of proteins through structural changes in the protein. Such structural changes propagate long distances, and this allostery plays a key role in molecular functions. However, the mechanism by which structural changes are transmitted is poorly understood. Here we show that nonbonded atomic contacts play an essential role in driving the displacement of a helix in picosecond time scale primary structural changes following the dissociation of carbon monoxide from the heme group in myoglobin. The present time-resolved ultraviolet resonance Raman study revealed that the amplitude of this helix displacement was reduced upon substitution of Val68, which contacts the heme in wild-type myoglobin, with a less bulky side chain (Ala). Our findings provided the first direct evidence that structural changes are transmitted not only by covalent bonds, salt bridges and hydrogen bonds but also by nonbonded atomic contacts in the primary protein response upon ligand dissociation. Furthermore, the present results indicate the importance of dense atomic packing in a protein structure for responding to the association and dissociation of small molecules. The high compactness of protein structures makes possible the propagation of structural changes, providing useful clues to the design of molecular machines.