U.S. Department of Energy Office of Scientific and Technical Information
Characterization of Americium and Curium Complexes with the Protein Lanmodulin: A Potential Macromolecular Mechanism for Actinide Mobility in the Environment
Journal Article·· Journal of the American Chemical Society
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Glenn T. Seaborg Inst.
Pennsylvania State Univ., University Park, PA (United States)
Massachusetts General Hospital and Harvard Medical School, Charlestown, MA (United States). Athinoula A. Martinos Center for Biomedical Imaging
Anthropogenic radionuclides, including long-lived heavy actinides such as americium and curium, represent the primary long-term challenge for management of nuclear waste. The potential release of these wastes into the environment necessitates understanding their interactions with biogeochemical compounds present in nature. Here, we characterize the interactions between the heavy actinides, Am3+ and Cm3+, and the natural lanthanide-binding protein, lanmodulin (LanM). LanM is produced abundantly by methylotrophic bacteria, including Methylorubrum extorquens, that are widespread in the environment. We determine the first stability constant for an Am3+-protein complex (Am3LanM) and confirm the results with Cm3LanM, indicating a ~5-fold higher affinity than that for lanthanides with most similar ionic radius, Nd3+ and Sm3+, and making LanM the strongest known heavy actinide-binding protein. The protein’s high selectivity over 243Am’s daughter nuclide 239Np enables lab-scale actinide-actinide separations as well as provides insight into potential protein-driven mobilization for these actinides in the environment. The luminescence properties of the Cm3+-LanM complex, and NMR studies of Gd3+-LanM, reveal that lanmodulin-bound f-elements possess two coordinated solvent molecules across a range of metal ionic radii. Finally, we show under a wide range of environmentally relevant conditions that lanmodulin effectively outcompetes desferrioxamine B, a hydroxamate siderophore previously proposed to be important in trivalent actinide mobility. Overall, these results suggest that natural lanthanide-binding proteins such as lanmodulin may play important roles in speciation and mobility of actinides in the environment; it also suggests that protein-based biotechnologies may provide a new frontier in actinide remediation, detection, and separations.
Deblonde, Gauthier J.-P., et al. "Characterization of Americium and Curium Complexes with the Protein Lanmodulin: A Potential Macromolecular Mechanism for Actinide Mobility in the Environment." Journal of the American Chemical Society, vol. 143, no. 38, Sep. 2021. https://doi.org/10.1021/jacs.1c07103
Deblonde, Gauthier J.-P., Mattocks, Joseph A., Wang, Huan, Gale, Eric M., Kersting, Annie B., Zavarin, Mavrik, & Cotruvo, Jr., Joseph A. (2021). Characterization of Americium and Curium Complexes with the Protein Lanmodulin: A Potential Macromolecular Mechanism for Actinide Mobility in the Environment. Journal of the American Chemical Society, 143(38). https://doi.org/10.1021/jacs.1c07103
Deblonde, Gauthier J.-P., Mattocks, Joseph A., Wang, Huan, et al., "Characterization of Americium and Curium Complexes with the Protein Lanmodulin: A Potential Macromolecular Mechanism for Actinide Mobility in the Environment," Journal of the American Chemical Society 143, no. 38 (2021), https://doi.org/10.1021/jacs.1c07103
@article{osti_1823692,
author = {Deblonde, Gauthier J.-P. and Mattocks, Joseph A. and Wang, Huan and Gale, Eric M. and Kersting, Annie B. and Zavarin, Mavrik and Cotruvo, Jr., Joseph A.},
title = {Characterization of Americium and Curium Complexes with the Protein Lanmodulin: A Potential Macromolecular Mechanism for Actinide Mobility in the Environment},
annote = {Anthropogenic radionuclides, including long-lived heavy actinides such as americium and curium, represent the primary long-term challenge for management of nuclear waste. The potential release of these wastes into the environment necessitates understanding their interactions with biogeochemical compounds present in nature. Here, we characterize the interactions between the heavy actinides, Am3+ and Cm3+, and the natural lanthanide-binding protein, lanmodulin (LanM). LanM is produced abundantly by methylotrophic bacteria, including Methylorubrum extorquens, that are widespread in the environment. We determine the first stability constant for an Am3+-protein complex (Am3LanM) and confirm the results with Cm3LanM, indicating a ~5-fold higher affinity than that for lanthanides with most similar ionic radius, Nd3+ and Sm3+, and making LanM the strongest known heavy actinide-binding protein. The protein’s high selectivity over 243Am’s daughter nuclide 239Np enables lab-scale actinide-actinide separations as well as provides insight into potential protein-driven mobilization for these actinides in the environment. The luminescence properties of the Cm3+-LanM complex, and NMR studies of Gd3+-LanM, reveal that lanmodulin-bound f-elements possess two coordinated solvent molecules across a range of metal ionic radii. Finally, we show under a wide range of environmentally relevant conditions that lanmodulin effectively outcompetes desferrioxamine B, a hydroxamate siderophore previously proposed to be important in trivalent actinide mobility. Overall, these results suggest that natural lanthanide-binding proteins such as lanmodulin may play important roles in speciation and mobility of actinides in the environment; it also suggests that protein-based biotechnologies may provide a new frontier in actinide remediation, detection, and separations.},
doi = {10.1021/jacs.1c07103},
url = {https://www.osti.gov/biblio/1823692},
journal = {Journal of the American Chemical Society},
issn = {ISSN 0002-7863},
number = {38},
volume = {143},
place = {United States},
publisher = {American Chemical Society (ACS)},
year = {2021},
month = {09}}