PDF(Pubmed)
Abstract：
Fast collective motions are widely present in biomolecules, but their functional relevance remains unclear. Herein, we reveal that fast collective motions of backbone are critical to the water transfer of aquaporin Z (AqpZ) by using solid-state nuclear magnetic resonance (ssNMR) spectroscopy and molecular dynamics (MD) simulations. A total of 212 residue site-specific dipolar order parameters and 158 15N spin relaxation rates of the backbone are measured by combining the 13C- and 1H-detected multidimensional ssNMR spectra. Analysis of these experimental data by theoretic models suggests that the small-amplitude (~10°) collective motions of the transmembrane α helices on the nanosecond-to-microsecond timescales are dominant for the dynamics of AqpZ. The MD simulations demonstrate that these collective motions are critical to the water transfer efficiency of AqpZ by facilitating the opening of the channel and accelerating the water-residue hydrogen bonds renewing in the selectivity filter region.
摘要：
快速的集体运动广泛存在于生物分子中，但它们的功能相关性仍不清楚。在这里，通过使用固态核磁共振（ssNMR）光谱和分子动力学（MD）模拟，我们发现骨架的快速集体运动对于水通道蛋白Z（AqpZ）的水转移至关重要。通过结合13C和1H检测的多维ssNMR光谱，测量了主链的总共212个残基位点特异性偶极有序参数和158个15N自旋弛豫速率。通过理论模型对这些实验数据的分析表明，跨膜α螺旋在纳秒至微秒时间尺度上的小振幅（〜10°）集体运动对于AqpZ的动力学是主要的。MD模拟表明，这些集体运动对AqpZ的水传递效率至关重要，因为它可以促进通道的打开并加速选择性过滤区域中的水-残留氢键的更新。
