Ruthenium(III) complexes are promising candidates for anticancer drugs, especially the clinically studied indazolium trans-[tetrachlorobis(1H-indazole)ruthenate(III)] (KP1019) and its analogue sodium trans-[tetrachlorobis(1H-indazole)ruthenate(III)] (NKP-1339). Several studies have emphasized the likely role of human serum proteins in the transportation and accumulation of ruthenium(III) complexes in tumors. Therefore, the interaction between KP1019 and human serum albumin was investigated by means of X-ray crystallography and inductively coupled plasma mass spectrometry (ICP-MS). The structural data unambiguously reveal the binding of two ruthenium atoms to histidine residues 146 and 242, which are both located within well-known hydrophobic binding pockets of albumin. The ruthenium centers are octahedrally coordinated by solvent molecules revealing the dissociation of both indazole ligands from the ruthenium-based drug. However, a binding mechanism is proposed indicating the importance of the indazole ligands for binding site recognition and thus their indispensable role for the binding of KP1019.

中文翻译：

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结合到人血清白蛋白上的吲哚鎓反式[四氯双（1 H-吲唑）钌（III）]（KP1019）的X射线结构分析揭示了两个钌结合位点并提供了对药物结合机理的见解

钌（III）配合物是抗癌药物的有希望的候选物，特别是经过临床研究的吲唑鎓反式-[[四氯双（1 H-吲唑）钌（III）]]（KP1019）及其类似物反式-[四氯双（1 H）钠-吲唑钌（III）]（NKP-1339）。多项研究强调了人类血清蛋白在钌（III）配合物在肿瘤中的运输和积累中的可能作用。因此，通过X射线晶体学和电感耦合等离子体质谱法（ICP-MS）研究了KP1019与人血清白蛋白之间的相互作用。结构数据清楚地揭示了两个钌原子与组氨酸残基146和242的结合，它们都位于白蛋白的众所周知的疏水结合口袋中。钌中心由溶剂分子八面体协调，揭示了两种吲唑配体都从基于钌的药物中解离。然而，