Unusually Broad-spectrum small-molecule sensing using a single protein scaffold.

Area of Science:

• Plant biology
• Biochemistry
• Chemical sensing

Background:

• Small-molecule sensing in plants often relies on chemical-induced dimerization.
• Abscisic acid (ABA) receptors exhibit sensitivity amplification, converting low-affinity interactions into high-affinity responses.
• This amplification mechanism suggests ABA receptors could be repurposed as versatile sensor scaffolds.

Purpose of the Study:

• To investigate the potential of ABA receptors as generic scaffolds for designing small-molecule sensors.
• To screen mutant ABA receptors against a large library of ligands to identify novel sensor functionalities.
• To develop a pipeline for designing and isolating ABA-based sensors with broad chemical scope.

Main Methods:

• Screening of mutant ABA receptors against 2,726 drugs and other ligands.
• Analysis of mutational patterns to identify ligand-specific binding pockets.
• Development of a sensor design pipeline based on experimental data.

Main Results:

• Identification of 569 ABA-based sensors, detecting 6.7% of tested ligands.
• Discovery of sensors for plant natural products, 2,4,6-trinitrotoluene (TNT), and per- and polyfluoroalkyl substances (PFAS).
• Demonstration of strong selection for ligand-specific binding pockets through mutational analysis.

Conclusions:

• The ABA receptor system is a viable and effective scaffold for designing small-molecule sensors.
• This approach enables the isolation of sensors with broad chemical scope and antibody-like simplicity.
• The developed pipeline facilitates the creation of custom sensors for diverse target molecules.