Biomineralized\nNuclear Receptor Protein-Selection Mass Spectrometry for the Discovery\nof Drugs and Toxics

Protein-selection mass spectrometry is cost-effective\nfor the discovery of drugs and toxics. Nuclear receptors (NRs) are\nmajor targets for pharmaceuticals and endocrine-disrupting chemicals\nand are, thus, widely used as “bait” proteins. However,\ntheir application is limited due to the tendency to lose protein activity\nduring cold storage. To address this problem, we introduced a novel\nbiomineralization-based approach to preserve activity in NRs, exemplified\nby human retinoic acid receptor alpha (hRARα), a target for\ncancer and leucocythemia therapy. Since information on the coordination\nchemistry of metal ion and NR protein complexes is almost unavailable,\nwe applied peptide mapping analysis for the first time for the rational\ndesign of his-hRARα–Co phosphate nanobiomaterial with\nhigh bioactivity. This nanobiomaterial successfully captured hRARα\nbioactive chemicals from a Chinese herb and environmental water and\ndiscovered an unsaturated fatty acid, (±)-(9<i>Z</i>,11<i>E</i>)-13-hydroxy-9,11-octadecadienoic acid ((±)13-HODE),\nwhich exhibited strong hRARα antagonistic activity.