Lordifard Parinaz, Shariatpanahi Seyed Peyman, Khajeh Khosro, Saboury Ali Akbar, Goliaei Bahram
Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
Department of Biochemistry, Faculty of Biological Science, Tarbiat Modares University, Tehran, Iran.
Int J Biol Macromol. 2024 Jan;254(Pt 3):127871. doi: 10.1016/j.ijbiomac.2023.127871. Epub 2023 Nov 10.
Our study aimed to investigate the effects of ultrasound on the fibrillation kinetics of HEWL (hen egg white lysozyme) and its physicochemical properties. Ultrasound, a mechanical wave, can induce conformational changes in proteins. To achieve this, we developed an ultrasound exposure system and used various biophysical techniques, including ThT fluorescence spectroscopy, ATR-FTIR, Far-UV CD spectrophotometry, Fluorescence microscopy, UV-spectroscopy, and seeding experiments. Our results revealed that higher frequencies significantly accelerated the fibrillation of lysozyme by unfolding the native protein and promoting the fibrillation process, thereby reducing the lag time. We observed a change in the secondary structure of the sonicated protein change to the β-structure, but there was no difference in the T of native and sonicated proteins. Furthermore, we found that higher ultrasound frequencies had a greater seeding effect. We propose that the effect of frequency can be explained by the impact of the Reynolds number, and for the Megahertz frequency range, we are almost at the transition regime of turbulence. Our results suggest that laminar flows may not induce any significant change in the fibrillation kinetics, while turbulent flows may affect the process.
我们的研究旨在探究超声对蛋清溶菌酶（HEWL）的纤维化动力学及其物理化学性质的影响。超声作为一种机械波，可诱导蛋白质的构象变化。为实现这一目标，我们开发了一种超声暴露系统，并使用了多种生物物理技术，包括硫黄素T荧光光谱法、衰减全反射傅里叶变换红外光谱法、远紫外圆二色分光光度法、荧光显微镜、紫外光谱法和接种实验。我们的结果表明，较高频率通过使天然蛋白质解折叠并促进纤维化过程，显著加速了溶菌酶的纤维化，从而缩短了延迟时间。我们观察到超声处理后的蛋白质二级结构转变为β结构，但天然蛋白质和超声处理后的蛋白质的熔点并无差异。此外，我们发现较高的超声频率具有更大的接种效应。我们认为，频率的影响可以用雷诺数的作用来解释，在兆赫兹频率范围内，我们几乎处于湍流的过渡区域。我们的结果表明，层流可能不会在纤维化动力学上引起任何显著变化，而湍流可能会影响这一过程。
