%0 Journal Article %A Hackler, Amber L. %A FitzGerald, Forrest G. %A Dang, Vuong Q. %A Satz, Alexander L. %A Paegel, Brian M. %D 2019 %T Off-DNA DNA-Encoded Library Affinity Screening %U https://acs.figshare.com/articles/journal_contribution/Off-DNA_DNA-Encoded_Library_Affinity_Screening/11481954 %R 10.1021/acscombsci.9b00153.s001 %2 https://acs.figshare.com/ndownloader/files/20502564 %K target classes %K Off-DNA DNA-Encoded Library Affinity Screening DNA-encoded library %K in-droplet laser-induced fluorescence polarization %K droplet-based microfluidic screening %K acid binding proteins %K DDR 1 %K target binding %K receptor tyrosine kinase %K molecule discovery toolbox %K activity assay %K combinatorial libraries %K DNA tags %K RTK inhibitor pharmacophores %K 67 100- %K discoidin domain receptor 1 %K droplet-scale competition-binding assay %K influence target binding %K FP detection %K DEL member %K DNA tag %K protein target %K proof-of-concept target %K obviating DNA tag interference %K Off-DNA DEL affinity screening %K quinazolinone-containing monomers %K 67 100- member solid-phase DEL %K solid-phase DEL %K Conventional DEL screens %K affinity selection %K DNA-tagged library members %K experiment outcome %X DNA-encoded library (DEL) technology is emerging as a key element of the small molecule discovery toolbox. Conventional DEL screens (i.e., on-DNA screening) interrogate large combinatorial libraries via affinity selection of DNA-tagged library members that are ligands of a purified and immobilized protein target. In these selections, the DNA tags can materially and undesirably influence target binding and, therefore, the experiment outcome. Here, we use a solid-phase DEL and droplet-based microfluidic screening to separate the DEL member from its DNA tag (i.e., off-DNA screening), for subsequent in-droplet laser-induced fluorescence polarization (FP) detection of target binding, obviating DNA tag interference. Using the receptor tyrosine kinase (RTK) discoidin domain receptor 1 (DDR1) as a proof-of-concept target in a droplet-scale competition-binding assay, we screened a 67 100-member solid-phase DEL of drug-like small molecules for competitive ligands of DDR1 and identified several known RTK inhibitor pharmacophores, including azaindole- and quinazolinone-containing monomers. Off-DNA DEL affinity screening with FP detection is potentially amenable to a wide array of target classes, including nucleic acid binding proteins, proteins that are difficult to overexpress and purify, or targets with no known activity assay. %I ACS Publications