In situ EPR spectroscopy of a bacterial membrane transporter using an expanded genetic code

The membrane transporter BtuB is site-directedly spin labelled on the surface of living Escherichia coli via Diels-Alder click chemistry of the genetically encoded amino acid SCO-l-lysine. The previously introduced photoactivatable nitroxide PaNDA prevents off-target labelling, is used for distance measurements, and the temporally shifted activation of the nitroxide allows for advanced experimental setups. This study describes significant evolution of Diels-Alder-mediated spin labelling on cellular surfaces and opens up new vistas for the the study of membrane proteins.

Automated summary

This study successfully conducts spin labelling on cellular surfaces through Diels-Alder chemistry, providing new methods for the study of membrane proteins.