Illustration of peptoid combinations. Each of the metal-binding monomers is represented as a red or blue “claw.” Credit: Rebecca Abergel/Berkeley Lab
A team of researchers at Berkeley Lab, led by alumna Rebecca Abergel, have developed a library of artificial proteins or “peptoids” that effectively “chelate” or bind to lanthanides and actinides, heavy metals that make up the so-called f-block elements at the bottom of the periodic table.
The new library offers researchers an automated, high-throughput method for precisely designing new peptoids – protein-like polymers with a precise sequence of monomer units – that chelate lanthanides such as gadolinium, a common ingredient in MRI contrast agents, and actinides such as plutonium.
As reported in the journal Chemical Science, the researchers incorporated custom-made monomers with f-block-binding properties onto peptoid scaffolds at Berkeley Lab’s Molecular Foundry. In this initial study, the researchers assembled two bio-inspired hydroxypyridinone and catecholamide monomers onto molecular complexes called “tetramers,” yielding a library of 16 chelating peptoids (also known as “ligands”). The researchers then used a luminescence-based technique to measure how well each chelating peptoid coordinated to the lanthanide cations (positively charged ions) europium and terbium.