Genetically encoded unnatural amino acids are useful tools for controlling protein function, but options for sequential activation of proteins using light as a trigger are limited. Here, we report the genetic encoding of two new photocaged lysine derivatives for activation of protein function, such as protein translocation and bioluminescence, with two different wavelengths of light and/or different durations of light exposure.

Abstract

Genetically encoded unnatural amino acids are versatile tools for controlling protein function, but options for regulating multiple proteins in a single experiment are limited. Here, we report the genetic encoding of two new photocaged lysine derivatives, 1-(2-nitrophenyl)-ethyl lysine and nitrodibenzylfuranyl lysine, for sequential light-activation of protein function in live cells. Nitrodibenzylfuranyl (NDBF) caging groups have a redshifted absorbance maximum and high sensitivity to light compared to the 1-(2-nitrophenyl)-ethyl group (NPE), enabling selective decaging and protein activation. We characterized the responses of these new caged amino acids by optically triggering nuclear localization and firefly luciferase activity. The ability to selectively activate distinct proteins through simple light titration makes this a useful approach with broad applications.