Characterization of protein solutions is of great importance for biophysical research, pharmaceutical industry, and medicine. Particularly, the monitoring of the protein aggregation is crucial at all stages of biotechnological production and in the diagnosis of dangerous diseases. The present work is focused on a study of prospects and possibilities of NMR relaxation of solvent nuclei for monitoring the state of proteins in solutions. The spin–lattice and spin–spin relaxation rates (R₁ and R₂) of solvent nuclei were measured in the solutions of a small globular protein, RRM2 domain of TDP-43 protein. The solvent was either H₂O- or D₂O-based buffer with pH 6.5 and contained 20 mM sodium phosphate and 150 mM NaCl. The relaxation rates of the solvent ¹H, ²H, ²³Na, and ³⁵Cl nuclei in solutions of soluble and aggregated RRM2 domain of TDP-43 protein were studied. The aggregation was induced by mild oxidative stress, using treatment by hydrogen peroxide. It was found that aggregation of protein could be detected using NMR relaxation of ¹H nuclei. The observed CPMG dispersion for R₂ rates confirms the millisecond timescale for the hydrogen exchange between water and protein sites. The correlation times and binding constants for sodium and chlorine ions were estimated using concentration dependences for relaxation rates (²³Na, ³⁵Cl). The relaxation rates of solvent nuclei are sensitive to the presence of protein in solution even at low protein concentrations, and the relaxation rates of different nuclei reflect various aspects of the state of the protein.

蛋白质溶液的表征对于生物物理研究，制药工业和医学至关重要。特别是，蛋白质聚集的监测在生物技术生产的所有阶段以及危险疾病的诊断中都至关重要。目前的工作集中在研究溶剂核的NMR弛豫以监测溶液中蛋白质状态的前景和可能性。在小球状蛋白，TDP-43蛋白的RRM2结构域的溶液中测量了溶剂核的自旋-晶格和自旋-自旋弛豫速率（R ₁和R ₂）。溶剂为H ₂ O-或D ₂O型缓冲液，pH值为6.5，含有20 mM磷酸钠和150 mM NaCl。研究了溶剂¹ H，² H，²³ Na和³⁵ Cl核在TDP-43蛋白的可溶性和聚集RRM2结构域溶液中的弛豫率。使用过氧化氢处理，通过轻度的氧化应激诱导聚集。发现可以使用¹ H核的NMR弛豫来检测蛋白质的聚集。观察到的R _2的CPMG色散速率确定了水和蛋白质位点之间氢交换的毫秒级时间尺度。钠和氯离子的相关时间和结合常数是使用弛豫速率（²³ Na，³⁵ Cl）的浓度依赖性估算的。即使在低蛋白质浓度下，溶剂核的弛豫速率也对溶液中蛋白质的存在敏感，并且不同核的弛豫速率反映了蛋白质状态的各个方面。