biostudies-literatureUnknown95(18)Clackson TFKBP ligand homodimers can be used to activate signaling events inside cells and animals that have been engineered to express fusions between appropriate signaling domains and FKBP. However, use of these dimerizers in vivo is potentially limited by ligand binding to endogenous FKBP. We have designed ligands that bind specifically to a mutated FKBP over the wild-type protein by remodeling an FKBP-ligand interface to introduce a specificity binding pocket. A compound bearing an ethyl substituent in place of a carbonyl group exhibited sub-nanomolar affinity and 1,000-fold selectivity for a mutant FKBP with a compensating truncation of a phenylalanine residue. Structural and functional analysis of the new pocket showed that recognition is surprisingly relaxed, with the modified ligand only parProceedings of the National Academy of Sciences of the United States of America10437-42https://www.ebi.ac.uk/biostudies/studies/S-EPMC27912biostudies-literatureRedesigning an FKBP-ligand interface to generate chemical dimerizers with novel specificity.PMC27912Rollins CTLu XRozamus LWGilman MStevenson LFYang WWood SAAmara JFCerasoli FClackson THatada MMagari SRCourage NLHolt DAfalseRedesigning an FKBP-ligand interface to generate chemical dimerizers with novel specificity.FKBP ligand homodimers can be used to activate signaling events inside cells and animals that have been engineered to express fusions between appropriate signaling domains and FKBP. However, use of these dimerizers in vivo is potentially limited by ligand binding to endogenous FKBP. We have designed ligands that bind specifically to a mutated FKBP over the wild-type protein by remodeling an FKBP-ligand interface to introduce a specificity binding pocket. A compound bearing an ethyl substituent in place of a carbonyl group exhibited sub-nanomolar affinity and 1,000-fold selectivity for a mutant FKBP with a compensating truncation of a phenylalanine residue. Structural and functional analysis of the new pocket showed that recognition is surprisingly relaxed, with the modified ligand only par1998-01-01T00:00:00Z1998 Sep2025-04-04T19:06:42.202Z2019-03-27T00:17:56ZS-EPMC27912972472110.1073/pnas.95.18.10437