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How Does Iron Storage Protein Ferritin Interact with Plutonium (and Thorium)?
Author(s) -
Zurita Cyril,
Tsushima Satoru,
Bresson Carole,
Garcia Cortes Marta,
Solari Pier Lorenzo,
Jeanson Aurélie,
Creff Gaëlle,
Den Auwer Christophe
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202003653
Subject(s) - ferritin , thorium , chemistry , actinide , plutonium , ring (chemistry) , oxidation state , x ray absorption spectroscopy , crystallography , radiochemistry , absorption spectroscopy , inorganic chemistry , uranium , biochemistry , materials science , organic chemistry , physics , metallurgy , catalysis , quantum mechanics
The impact of the contamination of living organisms by actinide elements has been a constant subject of attention since the 1950s. But to date still little is understood. Ferritin is the major storage and regulation protein of iron in many organisms, it consists of a protein ring and a ferrihydric core at the center. This work sheds light on the interactions of early actinides (Th, Pu) at oxidation state +IV with ferritin and its ability to store those elements at physiological pH compared to Fe. The ferritin–thorium load curve suggests that Th IV saturates the protein (2840 Th atoms per ferritin) in a similar way that Fe does on the protein ring. Complementary spectroscopic techniques (spectrophotometry, infrared spectroscopy, and X‐ray absorption spectroscopy) were combined with molecular dynamics to provide a structural model of the interaction of Th IV and Pu IV with ferritin. Comparison of spectroscopic data together with MD calculations suggests that Th IV and Pu IV are complexed mainly on the protein ring and not on the ferrihydric core. Indeed from XAS data, there is no evidence of Fe neighbors in the Th and Pu environments. On the other hand, carboxylates from amino acids of the protein ring and a possible additional carbonate anion are shaping the cation coordination spheres. This thorough description from a molecular view point of Th IV and Pu IV interaction with ferritin, an essential iron storage protein, is a cornerstone in comprehensive nuclear toxicology.