Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, PL-30239 Krakow, Poland.
Department of Physical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, PL-30387 Krakow, Poland.
Int J Environ Res Public Health. 2022 Mar 17;19(6):3588. doi: 10.3390/ijerph19063588.
Physicochemical properties of poly-L-arginine (P-Arg) molecules in NaCl solutions were determined by molecular dynamics (MD) modeling and various experimental techniques. Primarily, the molecule conformations, the monomer length and the chain diameter were theoretically calculated. These results were used to interpret experimental data, which comprised the molecule secondary structure, the diffusion coefficient, the hydrodynamic diameter and the electrophoretic mobility determined at various ionic strengths and pHs. Using these data, the electrokinetic charge and the effective ionization degree of P-Arg molecules were determined. In addition, the dynamic viscosity measurements for dilute P-Arg solutions enabledto determine the molecule intrinsic viscosity, which was equal to 500 and 90 for ionic strength of 10 and 0.15 M, respectively. This confirmed that P-Arg molecules assumed extended conformations and approached the slender body limit at the low range of ionic strength. The experimental data were also used to determine the molecule length and the chain diameter, which agreed with theoretical predictions. Exploiting these results, a robust method for determining the molar mass of P-Arg samples, the hydrodynamic diameter, the radius of gyration and the sedimentation coefficient was proposed.
聚精氨酸（P-Arg）在氯化钠溶液中的物理化学性质通过分子动力学（MD）建模和各种实验技术来确定。首先，从理论上计算了分子构象、单体长度和链径。这些结果用于解释实验数据，包括在不同离子强度和 pH 值下测定的分子二级结构、扩散系数、水动力直径和电泳迁移率。利用这些数据，确定了 P-Arg 分子的动电电荷和有效电离度。此外，通过对稀 P-Arg 溶液的动态粘度测量，确定了分子的特性粘度，在离子强度为 10 和 0.15 M 时，分别为 500 和 90。这证实了 P-Arg 分子在低离子强度范围内呈现伸展构象，并接近细长体极限。实验数据还用于确定分子长度和链径，与理论预测相符。利用这些结果，提出了一种确定 P-Arg 样品摩尔质量、水动力直径、回转半径和沉降系数的可靠方法。
