PDF(Pubmed)
Abstract：
The substitution of leucine to proline at position 39 (p.P39L) in human αB-crystallin (αB-Cry) has been associated with conflicting interpretations of pathogenicity in cataracts and cardiomyopathy. This study aimed to investigate the effects of the p.P39L mutation on the structural and functional features of human αB-Cry. The mutant protein was expressed in Escherichia coli (E. coli) and purified using anion exchange chromatography. We employed a wide range of spectroscopic analyses, gel electrophoresis, transmission electron microscopy (TEM), and atomic force microscopy (AFM) techniques to investigate the structure, function, stability, and fibrillation propensity of the mutant protein. The p.P39L mutation caused significant changes in the secondary, tertiary, and quaternary structures of human αB-Cry and increased the thermal stability of the protein. The mutant αB-Cry exhibited an increased chaperone activity and an altered oligomeric size distribution, along with an increased propensity to form amyloid aggregates. It is worth mentioning, increased chaperone activity has important positive and negative effects on damaged cells related to cataracts and cardiomyopathy, particularly by interfering in the process of apoptosis. Despite the apparent positive nature of the increased chaperone activity, it is also linked to adverse consequences. This study provides important insights into the effect of proline substitution by leucine at the N-terminal region on the dual nature of chaperone activity in human αB-Cry, which can act as a double-edged sword.
摘要：
39位亮氨酸被脯氨酸取代（p。人αB-晶状体蛋白（αB-Cry）中的P39L）与白内障和心肌病中致病性的相互矛盾的解释有关。本研究旨在研究p的影响。人αB-Cry的结构和功能特征上的P39L突变。突变蛋白在大肠杆菌中表达（E。大肠杆菌），并使用阴离子交换色谱法纯化。我们采用了广泛的光谱分析，凝胶电泳,透射电子显微镜（TEM），和原子力显微镜（AFM）技术来研究结构，函数,稳定性,和突变蛋白的纤颤倾向。p.P39L突变引起次级的显著变化,第三级,和人αB-Cry的四级结构，并增加了蛋白质的热稳定性。突变体αB-Cry表现出增加的伴侣活性和改变的寡聚物大小分布，随着形成淀粉样蛋白聚集体的倾向增加。值得一提的是,伴侣活性的增加对与白内障和心肌病相关的受损细胞具有重要的正面和负面影响，特别是通过干扰细胞凋亡的过程。尽管伴侣活动的增加具有明显的积极性质，这也与不利后果有关。这项研究为亮氨酸在N端区域的脯氨酸取代对人αB-Cry伴侣活性的双重性质的影响提供了重要的见解，这可以作为一把双刃剑。
