Liu Qi, Wang Jingkang, Huang Xin, Wu Hao, Zong Shuyi, Cheng Xiaowei, Hao Hongxun
National Engineering Research Center of Industrial Crystallization Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China.
State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, People's Republic of China.
IUCrJ. 2022 Apr 27;9(Pt 3):370-377. doi: 10.1107/S2052252522003001. eCollection 2022 May 1.
Water confined or constrained in a cellular environment can exhibit a diverse structural and dynamical role and hence will affect the self-assembly behavior of biomolecules. Herein, the role of water in the formation of l-phenyl-alanine crystals and amyloid fibrils was investigated. A microemulsion biomimetic system with controllable water pool size was employed to provide a microenvironment with different types of water, which was characterized by small-angle X-ray scattering, attenuated total reflectance-Fourier transform infrared spectroscopy and differential scanning calorimetry. In a bound water environment, only plate-like l-phenyl-alanine crystals and their aggregates were formed, all of which are anhydrous crystal form I. However, when free water dominated, amyloid fibrils were observed. Free water not only stabilizes new oligomers in the initial nucleation stage but also forms bridged hydrogen bonds to induce vertical stacking to form a fibrous structure. The conformational changes of l-phenyl-alanine in different environments were detected by NMR. Different types of water trigger different nucleation and growth pathways, providing a new perspective for understanding molecular self-assembly in nanoconfinement.
在细胞环境中受限或受约束的水可以表现出多样的结构和动力学作用，因此会影响生物分子的自组装行为。在此，研究了水在L-苯丙氨酸晶体和淀粉样纤维形成中的作用。采用具有可控水池大小的微乳液仿生系统来提供具有不同类型水的微环境，该微环境通过小角X射线散射、衰减全反射傅里叶变换红外光谱和差示扫描量热法进行表征。在结合水环境中，仅形成了片状L-苯丙氨酸晶体及其聚集体，所有这些都是无水晶型I。然而，当自由水占主导时，观察到了淀粉样纤维。自由水不仅在初始成核阶段稳定新的寡聚物，还形成桥连氢键以诱导垂直堆积形成纤维结构。通过核磁共振检测了不同环境中L-苯丙氨酸的构象变化。不同类型的水引发不同的成核和生长途径，为理解纳米限域中的分子自组装提供了新的视角。
