The complexation of Cm(III) with the recombinant human serum albumin (rHSA) (characterized by single deletion of residue Asp-1), is studied in dependence of pH and rHSA concentration using time-resolved laser fluorescence spectroscopy (TRLFS). A Cm(III) rHSA species is formed between pH 6.4 and 10.0 with the conditional stability constant being logK = 6.47 at pH = 7.4. Competition titration experiments with Cu(II) and Zn(II) confirm complexation at the N-terminal binding site (NTS) of rHSA and exclude the involvement of the Multi-Metal Binding Site (MBS). Comparison with a previous study on Cm(III) interaction with native albumin, HSA, points out, that residue Asp-1 is involved in Cm(III) binding to HSA but is not crucial for Cm(III) complexation at the NTS. The results are of major importance for a better understanding of fundamental actinide-protein interaction mechanisms which are highly required for the identification and characterization of relevant distribution pathways of incorporated radionuclides.

中文翻译：

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Cm(III) 与血清蛋白的复合：重组人血清白蛋白 (rHSA)

使用时间分辨激光荧光光谱 (TRLFS) 研究 Cm(III) 与重组人血清白蛋白 (rHSA)（以残基 Asp-1 的单个缺失为特征）的络合与 pH 和 rHSA 浓度的关系。Cm(III) rHSA 物质在 pH 6.4 和 10.0 之间形成，条件稳定性常数为 logK = 6.47，pH = 7.4。Cu(II) 和 Zn(II) 的竞争滴定实验证实了 rHSA 的 N 端结合位点 (NTS) 的络合，并排除了多金属结合位点 (MBS) 的参与。与先前关于 Cm(III) 与天然白蛋白 HSA 相互作用的研究的比较指出，残基 Asp-1 参与 Cm(III) 与 HSA 的结合，但对 NTS 处的 Cm(III) 络合并不重要。