Living matter is a quasi-stationary out-of-equilibrium system; in this physical condition, structural fluctuations at nano- and meso-scales are needed to understand the physics behind its biological functionality. Myelin has a simple ultrastructure whose fluctuations show correlated disorder in its functional out-of-equilibrium state. However, there is no information on the relationship between this correlated disorder and the dynamics of the intrinsically disordered Myelin Basic Protein (MBP) which is expected to influence the membrane structure and overall functionality. In this work, we have investigated the role of this protein structural dynamics in the myelin ultrastructure fluctuations in various conditions, by using synchrotron Scanning micro X Ray Diffraction and Small Angle X ray Scattering. We have induced the crossover from out-of-equilibrium functional state to in-equilibrium degeneration changing the pH to values far from physiological condition.

The observed compression of the cytosolic layer thickness probes that the intrinsic large MBP fluctuations preserve the cytosol structure also in the degraded state. Thus, the transition of myelin ultrastructure from correlated to uncorrelated disordered state, is principally affected by the deformation of the membrane and extracellular domain.

生物是一种准平稳的失衡系统；在这种物理条件下，需要了解纳米和中尺度的结构波动，以了解其生物学功能背后的物理原理。髓磷脂具有简单的超微结构，其波动显示出其功能失衡状态的相关障碍。但是，没有有关此相关疾病与固有失调的髓鞘碱性蛋白（MBP）动力学之间关系的信息，后者预期会影响膜结构和整体功能。在这项工作中，我们通过使用同步加速器扫描微X射线衍射和小角度X射线散射研究了这种蛋白质结构动力学在各种条件下髓磷脂超结构波动中的作用。

观察到的对胞浆层厚度的压缩表明，固有的较大的MBP波动也使细胞溶胶结构保持在降解状态。因此，髓磷脂超微结构从相关无序状态到不相关无序状态的转变主要受膜和细胞外结构域变形的影响。