On the structure of thorium and americium adenosine triphosphate complexes

Abstract

Purpose: The actinides are chemical poisons and radiological hazards. One challenge to better appraise their toxicity and develop countermeasures in case of exposure of living organisms is to better assess pathways of contamination. Because of the high chemical affinity of those actinide elements for phosphate groups and the ubiquity of such chemical functions in biochemistry, nucleotides and in particular adenosine triphosphate nucleotide (ATP) may be considered critical target building blocks for actinides.

Materials and methods: Combinations of spectroscopic techniques (Fourier transformed Infra Red [FTIR], Electrospray Ionization Mass Spectrometry [ESI-MS], and Extended X-ray Absorption Fine Structure [EXAFS]) with quantum chemical calculations have been implemented in order to assess the actinides coordination arrangement with ATP.

Results: We describe and compare herein the interaction of ATP with thorium and americium; thorium(IV) as a representative of actinide(IV) like plutonium(IV) and americium(III) as a representative of all heavier actinides. In the case of thorium, an insoluble complex is readily formed. In the case of americium, a behavior identical to that described previously for lutetium has been observed with insoluble and soluble complexes.

Conclusions: The comparative study of ATP complexation with Th(IV) and Am(III) shows their ability to form insoluble complexes for which a structural model has been proposed by analogy with previously described Lu(III) complexes.

Keywords::

• Radionuclides
• biochemistry
• environmental effects

Acknowledgements

This work was managed by the Commissariat à l’Energie Atomique (CEA), Nuclear Energy Division under the RBPCH (Basic Research for Physical Chemistry) Program. The authors would like also to acknowledge the French Toxicological program of CEA for funding support. XAS experiments were performed at the SOLEIL synchrotron, at the dedicated beam line for radioactive materials (MARS beam line).

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.