Dömötör Orsolya, Rathgeb Anna, Kuhn Paul-Steffen, Popović-Bijelić Ana, Bačić Goran, Enyedy Eva Anna, Arion Vladimir B
Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary; MTA-SZTE Bioinorganic Chemistry Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary.
University of Vienna, Institute of Inorganic Chemistry, Währinger Strasse 42, A-1090, Vienna, Austria.
J Inorg Biochem. 2016 Jun;159:37-44. doi: 10.1016/j.jinorgbio.2016.02.003. Epub 2016 Feb 11.
Overall binding affinity of sodium or indazolium cis/trans-[MCl4(1H-indazole)(NO)] (M = Ru, Os) complexes towards human serum albumin (HSA) and high molecular mass components of the blood serum was monitored by ultrafiltration. HSA was found to be mainly responsible for the binding of the studied ruthenium and osmium complexes. In other words, this protein can provide a depot for the compounds and can affect their biodistribution and transport processes. In order to elucidate the HSA binding sites tryptophan fluorescence quenching studies and displacement reactions with the established site markers warfarin and dansylglycine were performed. Conditional stability constants for the binding to sites I and II on HSA were computed showing that the studied ruthenium and osmium complexes are able to bind into both sites with moderately strong affinity (logK' = 4.4-5.1). Site I is slightly more favored over site II for all complexes. No significant differences in the HSA binding properties were found for these metal complexes demonstrating negligible influence of the type of counterion (sodium vs indazolium), the metal ion center identity (Ru vs. Os) or the position of the nitrosyl group on the binding event. Electron paramagnetic resonance spin labeling of HSA revealed that indazolium trans-[RuCl4(1H-indazole)(NO)] and long-chain fatty acids show competitive binding to HSA. Moreover, this complex has a higher affinity for site I, but when present in excess, it is able to bind to site II as well, and displace fatty acids.
通过超滤监测了钠或吲唑顺式/反式-[MCl₄(1H-吲唑)(NO)]（M = Ru，Os）配合物与人血清白蛋白（HSA）以及血清高分子质量成分的总体结合亲和力。发现HSA是所研究的钌和锇配合物结合的主要原因。换句话说，这种蛋白质可以为这些化合物提供一个储存库，并能影响它们的生物分布和运输过程。为了阐明HSA结合位点，进行了色氨酸荧光猝灭研究以及与已确定的位点标记物华法林和丹磺酰甘氨酸的置换反应。计算了与HSA上I位点和II位点结合的条件稳定常数，结果表明所研究的钌和锇配合物能够以中等强度的亲和力结合到这两个位点（logK' = 4.4 - 5.1）。对于所有配合物，I位点比II位点略受青睐。这些金属配合物在HSA结合特性方面未发现显著差异，表明抗衡离子类型（钠与吲唑）、金属离子中心身份（Ru与Os）或亚硝酰基位置对结合事件的影响可忽略不计。HSA的电子顺磁共振自旋标记显示，反式吲唑-[RuCl₄(1H-吲唑)(NO)]和长链脂肪酸对HSA表现出竞争性结合。此外，该配合物对I位点具有更高的亲和力，但当过量存在时，它也能够结合到II位点并置换脂肪酸。
