Chemigenetic indicators based on synthetic chelators and green fluorescent protein

Nat Chem Biol. 2023 Jan;19(1):38-44. doi: 10.1038/s41589-022-01134-z. Epub 2022 Sep 22.


Molecular fluorescent indicators are versatile tools for dynamic imaging of biological systems. We now report a class of indicators that are based on the chemigenetic combination of a synthetic ion-recognition motif and a protein-based fluorophore. Specifically, we have developed a calcium ion (Ca2+) indicator that is based on genetic insertion of circularly permuted green fluorescent protein into HaloTag protein self-labeled with a ligand containing the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid. We have demonstrated the versatility of this design by also developing a sodium ion (Na+) indicator using a crown-ether-containing ligand. This approach affords bright and sensitive ion indicators that can be applicable to cell imaging. This design can enable the development of chemigenetic indicators with ion or molecular specificities that have not been realized with fully protein-based indicators.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium* / metabolism
  • Chelating Agents*
  • Fluorescent Dyes
  • Green Fluorescent Proteins / genetics
  • Ligands
  • Sodium


  • Chelating Agents
  • Green Fluorescent Proteins
  • Ligands
  • Calcium
  • Fluorescent Dyes
  • Sodium