Described herein is a method of selecting allosteric
biosensor proteins which bind a target ligand. The method includes providing a
library of replicating plasmids each including an expression construct and a reporter, wherein each expression construct includes a
gene encoding the allosteric
protein variant and the reporter, wherein the reporter includes a
barcode sequence for identification of the allosteric
protein variant or allosteric domain variant. The method further includes mapping the variants in the
library to the
barcode sequence or sequences associated with the variant and assigning variant-
barcode pairs, growing a
population of cells transfected with the
library of replicating plasmids in the presence of the target ligand and isolating target ligand
total RNA and target ligand library plasmids; performing next generation sequencing to determine a quantity of each barcode in the target ligand
total RNA, determining a fold enrichment for each allosteric
protein variant or allosteric domain variant in the target ligand
total RNA, and selecting a subpopulation of variants with the highest fold enrichment as the selected allosteric biosensors.