Protein Crystallization Provides Insight into Actinide Coordination

The diverse implications in understanding the biological chemistry of the actinides are profound, demonstrated in both the decontamination efforts of individuals after a nuclear accident and the remedial use of radionuclides for cancer treatments and diagnostics. Underpinning these efforts aimed to address critical societal challenges is a thorough understanding of <i>f</i>-element binding and coordination behavior in the presence of biologically-inspired systems. Despite advances in probing the fundamental properties of the actinides through methods such as X-ray Absorption Spectroscopy, opportunities to expand our current understanding at the interface between small molecule actinide complexes and natural systems can be further aided by the use of macromolecular hosts. By combining hard oxygen-donor chelators that bind actinides with high-specificity and utilizing a protein called siderocalin, which has been shown to selectively bind a diverse range of actinide complexes, these ‘actinide-chelator-macromolecule’ constructs can be crystallized to reveal the fundamental bonding of even the rarest of actinide elements. Protein crystallographic measurements collected at the Advanced Light Source (Beamline 5.0.2) enable actinide coordination to be revealed in the solid-state, and more broadly can help probe the interactions between biological scaffolds and actinide materials.