Laurent Harrison, Youngs Tristan G A, Headen Thomas F, Soper Alan K, Dougan Lorna
School of Physics and Astronomy, University of Leeds, Leeds, UK.
ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot, UK.
Commun Chem. 2022 Sep 28;5(1):116. doi: 10.1038/s42004-022-00726-z.
Trimethylamine N-oxide (TMAO) protects organisms from the damaging effects of high pressure. At the molecular level both TMAO and pressure perturb water structure but it is not understood how they act in combination. Here, we use neutron scattering coupled with computational modelling to provide atomistic insight into the structure of water under pressure at 4 kbar in the presence and absence of TMAO. The data reveal that TMAO resists pressure-induced perturbation to water structure, particularly in retaining a clear second solvation shell, enhanced hydrogen bonding between water molecules and strong TMAO - water hydrogen bonds. We calculate an 'osmolyte protection' ratio at which pressure and TMAO-induced energy changes effectively cancel out. Remarkably this ratio translates across scales to the organism level, matching the observed concentration dependence of TMAO in the muscle tissue of organisms as a function of depth. Osmolyte protection may therefore offer a molecular mechanism for the macroscale survival of life in extreme environments.
氧化三甲胺（TMAO）可保护生物体免受高压的破坏作用。在分子层面，TMAO和压力都会扰乱水的结构，但目前尚不清楚它们如何共同作用。在此，我们结合中子散射和计算模型，以深入了解在4千巴压力下，有无TMAO时水的结构。数据表明，TMAO可抵抗压力对水结构的扰动，尤其是在保持清晰的第二溶剂化层、增强水分子间氢键以及形成强大的TMAO-水氢键方面。我们计算了一个“渗透质保护”比率，在该比率下，压力和TMAO诱导的能量变化可有效抵消。值得注意的是，这个比率在不同尺度上都能转化到生物体层面，与观察到的生物体肌肉组织中TMAO浓度随深度的依赖性相匹配。因此，渗透质保护可能为极端环境中生命的宏观生存提供一种分子机制。
