Coiled coils as ligands for inclusion in the inorganic chemist's toolbox – For advances in MRI contrast agent design

Ligands are essential tools in synthetic inorganic chemistry, enabling the fine-tuning of metal ion properties to optimize performance. Spanning from small molecules to macromolecular proteins, ligands vary widely in structure and function. De novo designed coiled coils serve as a unique bridge between these extremes, offering precise control over metal coordination. Here, we explore the application of coiled coil ligands in MRI contrast agent design, leveraging their versatility to systematically modulate the coordination chemistry and hydration state of gadolinium - the metal used in most clinical MRI contrast agents. This novel class of gadolinium-based agents demonstrates superior performance compared to existing clinical agents, highlighting the potential of coiled coil ligands. Furthermore, when coordinated to copper, these ligands form complexes that challenge the conventional notion that copper is unsuitable for MRI contrast agents. These findings establish coiled coil ligands as a powerful platform for advancing contrast agent design.