Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland.
Institute of Chemical Sciences and Engineering, EPFL CH C2 425, Bâtiment CH, Station 6, Lausanne CH-1015, Switzerland.
J Phys Chem Lett. 2022 Jan 13;13(1):112-117. doi: 10.1021/acs.jpclett.1c03596. Epub 2021 Dec 28.
The equilibrium constant () of biochemical complex formation in aqueous buffers with high concentration (>20 wt %) of nonionic compounds can vary by orders of magnitude in comparison with the in a pure buffer. The precise molecular mechanisms of these profound changes are not known. Herein, we show up to a 1000-fold decrease of the value of DNA hybridization (at nM concentration) in standard molecular crowder systems such as PEG, dextrans, Ficoll, and glycerol. The effect responsible for the decrease of is the complexation of positively charged ions from a buffer by nonionic polymers/small molecules. We determined the average equilibrium constant for the complexation of ions per monomer (∼0.49 M). We retrieve 's original value for a pure buffer if we properly increase the ionic strength of the buffer crowded by the polymers, compensating for the loss of complexed ions.
在高浓度（>20wt%）非离子化合物的水缓冲液中，生化复合物形成的平衡常数（）与纯缓冲液中的相比，可能会发生数量级的变化。这些深刻变化的确切分子机制尚不清楚。在此，我们展示了在标准分子拥挤系统（如 PEG、葡聚糖、Ficoll 和甘油）中，DNA 杂交（在 nM 浓度下）的降低高达 1000 倍。导致降低的原因是带正电荷的离子与非离子聚合物/小分子的复合。我们确定了每个单体离子复合的平均平衡常数（约为 0.49M）。如果我们适当增加被聚合物拥挤的缓冲液的离子强度，补偿复合离子的损失，我们就可以恢复“”在纯缓冲液中的原始值。
