Genetically Encoded Lysine Analogues with Differential Light Sensitivity for Activation of Protein Function.

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.