Somkuti J, Török Z, Pfalzgraf F, Smeller L
Hungarian Academy of Sciences-Semmelweis University, Molecular Biophysics Research Group, Budapest, Hungary.
Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.
Biophys Chem. 2017 Dec;231:125-134. doi: 10.1016/j.bpc.2017.04.013. Epub 2017 May 1.
The concentration of macromolecules inside a cell is very high, which can affect the behavior of the enzymes, and consequently influence vital biological processes. This is called macromolecular crowding. Since the most important effect of macromolecular crowding is the excluded volume, we performed pressure experiments, where the volume (as conjugate parameter to the pressure) is the crucial factor. We measured the temperature and pressure stability of bovine serum albumin and lysozyme with various concentrations of crowding agents, dextran, Ficoll™ and lysozyme itself. Our most interesting finding is that low concentration of all the studied crowding agents decreases the pressure stability of the proteins. We explain this by the reduced hydration volume change in the crowded environment. Furthermore, we discuss the volumetric parameters and emphasize the difference between the partial volume of the protein and the volume it influences, and their relation to the excluded volume which is responsible for the macromolecular crowding.
细胞内大分子的浓度非常高，这会影响酶的行为，进而影响重要的生物过程。这被称为大分子拥挤效应。由于大分子拥挤效应最重要的影响是排除体积，我们进行了压力实验，其中体积（作为压力的共轭参数）是关键因素。我们测量了牛血清白蛋白和溶菌酶在不同浓度的拥挤剂（葡聚糖、聚蔗糖™和溶菌酶本身）存在下的温度和压力稳定性。我们最有趣的发现是，所有研究的拥挤剂低浓度时都会降低蛋白质的压力稳定性。我们通过拥挤环境中水化体积变化的减少来解释这一现象。此外，我们讨论了体积参数，强调了蛋白质的偏摩尔体积与其所影响的体积之间的差异，以及它们与导致大分子拥挤效应的排除体积的关系。
