High-Throughput Screening Methods to Identify Small Molecule Targets

A method comprising:

• a) expressing on the surface of haploid yeast cells in a first culture one or both of:
• i) one or more wild-type targeting proteins;
• and/or,
• ii) one or more modified targeting proteins with at least one amino acid difference from the wild-type targeting protein;
• b) expressing on the surface of haploid yeast cells in a second culture one or both of:
• i) one or more wild-type target proteins;
• and/or,
• ii) one or more modified target proteins with at least one amino acid difference from the wild-type target protein;
• wherein the interaction between the wild-type target protein and the wild-type targeting protein has a dissociation constant (Kd) greater than about 100 nM;
• combining the first culture of haploid yeast cells and second culture of haploid yeast cells in a single liquid culture such that the binding of a targeting protein with a target protein leads to the formation of diploid yeast cells;
• and,
• determining, based on the number of mating events between the haploid yeast cells of the first and second cultures, the amino acid sequence mutations of the targeting protein and/or target protein, or both the targeting protein and the target protein, that result in a dissociation constant between the targeting protein and the target protein of about ten-fold less than the interaction between the wild-type target protein and the wild-type targeting protein.