Department of Biotechnology, Central University of Rajasthan, NH-8 Bandersindri, Kishangarh, Ajmer 305817, Rajasthan, India.
Institute of Nano Science and Technology, Mohali 160062, Punjab, India.
Int J Biol Macromol. 2021 Oct 1;188:512-522. doi: 10.1016/j.ijbiomac.2021.07.158. Epub 2021 Jul 29.
The loss of crystallins solubility with aging and the formation of amyloid-like aggregates is considered the hallmark characteristic of cataract pathology. The present study was carried out to assess the effect of temperature on the soluble lens protein and the formation of protein aggregates with typical amyloid characteristics. The soluble fraction of lens proteins was subjected for heat treatment in the range of 40-60 °C, and the nature of protein aggregates was assessed by using Congo red (CR), thioflavin T (ThT), and 8-anilinonaphthalene-1-sulfonic acid (ANS) binding assays, circular dichroism (CD), Fourier-transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). The heat-treated protein samples displayed a substantial bathochromic shift (≈15 nm) in the CR's absorption maximum (λ) and increased ThT and ANS binding. The heat treatment of lens soluble proteins results in the formation of nontoxic, β-sheet rich, non-fibrillar, protein aggregates similar to the structures evident in the insoluble fraction of proteins isolated from the cataractous lens. The data obtained from the present study suggest that the exposure of soluble lens proteins to elevated temperature leads to the formation of non-fibrillar aggregates, establishing the role of amyloid in the heat-induced augmentation of cataracts pathology.
随着年龄的增长,晶体蛋白的可溶性丧失以及类似淀粉样的聚集体的形成被认为是白内障病理的标志性特征。本研究旨在评估温度对可溶性晶状体蛋白和具有典型淀粉样特征的蛋白质聚集体形成的影响。将晶状体蛋白的可溶性部分在 40-60°C 的范围内进行热处理,并使用刚果红(CR)、硫黄素 T(ThT)和 8-苯胺萘-1-磺酸(ANS)结合测定、圆二色性(CD)、傅里叶变换红外(FT-IR)光谱和透射电子显微镜(TEM)来评估蛋白质聚集体的性质。热处理后的蛋白质样品在 CR 吸收最大值(λ)处显示出明显的红移(≈15nm),并且 ThT 和 ANS 结合增加。晶状体可溶性蛋白的热处理导致形成非毒性、富含β-片层、无纤维的蛋白质聚集体,类似于从白内障晶状体中分离的不溶性蛋白部分中存在的结构。本研究获得的数据表明,可溶性晶状体蛋白暴露于高温会导致形成无纤维聚集体,从而确立了淀粉样蛋白在热诱导的白内障病理增强中的作用。