Despite the successful clinical application of cisplatin, its mechanism of action and adverse effects remain poorly understood. To elucidate the complex pharmacology of this drug, research has focused on its interaction with proteins. Herein, we examined the interaction of cisplatin with calmodulin (CaM), a pivotal protein in signal transduction, and its effect upon binding to the MLCK kinase. Selective labeling of proteins, including ¹³CH₃-methionine- and ¹⁵N-labeled CaM, as well as ¹⁹F-tryptophan-labeled MLCK, enabled effective detection of protein folding and interactions using multiple NMR techniques. Results revealed that cisplatin readily reacts with CaM, leading to mobilization of bound Ca²⁺ ions and inhibition of CaM/MLCK complex formation. The preformed CaM/MLCK complex exhibited greater resilience to cisplatin, as compared to free CaM, due to more embedded methionine residues within the CaM/MLCK complex. Although the complex survived platination, it experienced some destabilization, as evidenced by the mobilization of some Ca²⁺ ions and the collapse of the complex under chromatographic conditions. Analogous reactions occur in a cellular setting. These results imply that the platination of CaM could underlie the mechanism of cisplatin-induced neurotoxicity.

中文翻译：

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探讨顺铂与钙调蛋白的相互作用及其对与肌球蛋白轻链激酶结合的影响


尽管顺铂的临床应用成功，但其作用机制和不良反应仍然知之甚少。为了阐明这种药物的复杂药理学，研究集中在它与蛋白质的相互作用上。在此，我们检查了顺铂与钙调蛋白 （CaM） 的相互作用，钙调蛋白 （CaM） 是信号转导中的关键蛋白，及其对与 MLCK 激酶结合的影响。蛋白质的选择性标记，包括 ¹³个_{CH 3}-蛋氨酸和 ¹⁵个 N 标记的 CaM，以及 ¹⁹个 F-色氨酸标记的 MLCK，能够使用多种 NMR 技术有效检测蛋白质折叠和相互作用。结果显示，顺铂易与 CaM 反应，导致结合的 Ca²⁺ 离子动员并抑制 CaM/MLCK 复合物的形成。与游离 CaM 相比，预制的 CaM/MLCK 复合物对顺铂表现出更大的弹性，因为 CaM/MLCK 复合物内嵌入了更多的蛋氨酸残基。尽管该复合物在镀铂化后幸存下来，但它经历了一些不稳定，一些 Ca²⁺ 离子的动员和复合物在色谱条件下的崩溃证明了这一点。类似的反应发生在细胞环境中。这些结果表明，CaM 的铂金化可能是顺铂诱导神经毒性机制的基础。