Green fluorescent protein is a staple tool for visualizing living cells.Credit: Sam Yeh/AFP via Getty
Researchers have engineered magnetically controlled fluorescent proteins that can be remotely dimmed and brightened in cells and living animals.
The hope is that these proteins’ magnetic sensitivity — a quantum effect — can be exploited to develop remote-controlled biosensors, or even therapies that can be turned on and off when needed.
“We want to make a toolbox of magnetically remote-controlled protein functions,” says Andrew York, a physicist at the Chan Zuckerberg Biohub in San Francisco, California. York is a co-author of a study, published today in Nature, that deployed the magnet-responsive proteins in bacteria1, as well as a co-author of a separate preprint study2 that demonstrated the use of similar proteins in nematode worms.
Magnetic dimming
Two years ago, while working at the biotechnology company Calico Life Sciences in South San Francisco, York and his former colleague biochemist Maria Ingaramo discovered that green fluorescent protein (GFP), a workhorse in biotechnology that is used to label other molecules, dims in the presence of a weak magnet3.
The effect was small — the brightness of GFP dimmed by about 1% near a magnet — so the researchers engineered a more responsive protein, called MagLOV, the fluorescence of which dims by half or more in the presence of a magnet.
To explore how best to harness MagLOV’s properties, a team led by biophysicist Gabriel Abrahams and bioengineer Harrison Steel, both at the University of Oxford, UK, tested the basis for its sensitivity to magnetic fields.
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In experiments described in the Nature paper, they found that MagLOV’s dimming was due to an effect in which the quantum properties of an electron pair in the protein could be altered by a magnetic field. In Escherichia coli cells that expressed MagLOV, this ‘magnetic resonance effect’ allowed the researchers to manipulate the brightness of the fluorescence with a combination of magnetic fields and radio waves.
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