Researchers created a protein that responds to… magnetic fields!

A team of researchers from Calico Life Sciences has developed a new protein that responds to, and hence can be controlled by, magnetic fields. This discovery, detailed in the pre-print paper titled “Magnetic control of the brightness of fluorescent proteins” (link at the end) reveals a novel way to manipulate the brightness of GFP-like fluorescent proteins using even modest magnetic fields of around 10 mT. Using this new, strongly magnetoresponsive protein is simple, non-toxic, and biocompatible, functioning effectively at both room temperature and body temperature. It has been tested in vitro, in E. coli, and in cultured mammalian cells.

Picture generated by the author from a CC-BY-3.0 picture of a magnet on Wikipedia (reusable even for commercial purposes) and a screenshot of the author’s own AlphaFold 3-based prediction of the structure of the protein discussed in the article.

The researchers found that fluorescent proteins, which are largely magnetically inert like most proteins, can become magnetoresponsive when paired with the right cofactor. For instance, EGFP and mScarlet, two common fluorescent proteins, showed magnetic responsiveness when combined with specific cofactors like FlavinTag for EGFP or a flavin mononucleotide (FMN) solution for mScarlet. This discovery paves the way for exciting technological advancements, such as lock-in detection, multiplexing, optically-detected MRI, and the development of magnetogenetics.

The work began when the researchers noted a weak magnetoresponse in a member of the LOV-domain family. By using techniques…