Iron-Binding Protein Transports Actinides Into Cells | Chemical & Engineering News
Volume 93 Issue 32 | p. 50 | Concentrates
Issue Date: August 17, 2015

Iron-Binding Protein Transports Actinides Into Cells

Radiochemistry: Siderocalin interacts with metal-binding ligands to relocate radioactive elements
Department: Science & Technology | Collection: Periodic table
News Channels: Biological SCENE, Environmental SCENE
Keywords: radiochemistry, radioactive, actinides
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The protein siderocalin, shown as a space-filling model, binds a complex of enterobactin and plutonium (center).
Credit: Roland Strong
The protein siderocalin bound to a complex of enterobactin and plutonium.
 
The protein siderocalin, shown as a space-filling model, binds a complex of enterobactin and plutonium (center).
Credit: Roland Strong

If released into the environment during an event such as a nuclear power plant leak, radioactive actinide metals would be a potential health risk. But little is known about how cells take up these elements. A research team led by Rebecca J. Abergel of Lawrence Berkeley National Laboratory and Roland K. Strong of the Fred Hutchinson Cancer Research Center, in Seattle, has shown that actinides might get inside cells by hitching a ride on a protein called siderocalin that’s usually involved in iron trafficking (Proc. Natl. Acad. Sci. USA 2015, DOI: 10.1073/pnas.1508902112). Siderocalin captures iron indirectly by forming a complex with ligands that bind iron. Because these ligands can bind multiple metals, that means siderocalin can as well. To demonstrate such binding, Abergel and coworkers obtained six crystal structures of siderocalin bound to various lanthanide and actinide complexes. The overall structures were remarkably similar, with only four of siderocalin’s amino acids adjusting to accommodate the various complexes. The researchers showed that cultured kidney cells took up siderocalin complexed with the ligand enterobactin bound to plutonium.

 
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