Université Côte d'Azur, CNRS, Institut de Chimie de Nice, 06108, Nice, France.
Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328, Dresden, Germany.
Chemistry. 2023 Oct 2;29(55):e202300636. doi: 10.1002/chem.202300636. Epub 2023 Sep 5.
Transferrin (Tf) is a glycoprotein that transports iron from the serum to the various organs. Several studies have highlighted that Tf can interact with metals other than Fe(III), including actinides that are chemical and radiological toxics. We propose here to report on the behavior of Th(IV) and Pu(IV) in comparison with Fe(III) upon Tf complexation. We considered UV-Vis and IR data of the M Tf complex (M=Fe, Th, Pu) and combined experimental EXAFS data with MD models. EXAFS data of the first M-O coordination sphere are consistent with the MD model considering 1 synergistic carbonate. Further EXAFS data analysis strongly suggests that contamination by Th/Pu colloids seems to occur upon Tf complexation, but it seems limited. SAXS data have also been recorded for all complexes and also after the addition of Deferoxamine-B (DFOB) in the medium. The Rg values are very close for apoTf, ThTf and PuTf, but slightly larger than for holoTf. Data suggest that the structure of the protein is more ellipsoidal than spherical, with a flattened oblate form. From this data, the following order of conformation size might be considered:holoTf<M Tf (M=Th, Pu)<apoTf<M Tf-DFOB (M=Fe, Th, Pu).
转铁蛋白（Tf）是一种糖蛋白，可将铁从血清转运至各个器官。多项研究强调，Tf 可以与除 Fe(III)之外的其他金属相互作用，包括化学和放射性毒物的类金属。在这里，我们提议报告 Tf 络合时 Th(IV)和 Pu(IV)与 Fe(III)的行为。我们考虑了 MTf 络合物（M=Fe、Th、Pu）的 UV-Vis 和 IR 数据，并将实验 EXAFS 数据与 MD 模型结合起来。第一 M-O 配位球的 EXAFS 数据与考虑到 1 个协同碳酸盐的 MD 模型一致。进一步的 EXAFS 数据分析强烈表明，在 Tf 络合时似乎会发生 Th/Pu 胶体的污染，但似乎是有限的。还记录了所有络合物的 SAXS 数据，以及在介质中添加去铁胺-B（DFOB）后的 SAXS 数据。apoTf、ThTf 和 PuTf 的 Rg 值非常接近，但略大于 holoTf。数据表明，该蛋白质的结构更呈椭圆形而不是球形，具有扁平的扁球体形状。根据这些数据，可以考虑以下构象大小顺序：holoTf<M Tf（M=Th、Pu）<apoTf<M Tf-DFOB（M=Fe、Th、Pu）。
