Disentangling the recognition complexity of a protein hub using a nanopore.

Mayse, Lauren Ashley; Imran, Ali; Larimi, Motahareh Ghahari; Cosgrove, Michael S; Wolfe, Aaron James; Movileanu, Liviu · Nat Commun · 2022

basic_science · Level V

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Abstract

WD40 repeat proteins are frequently involved in processing cell signaling and scaffolding large multi-subunit machineries. Despite their significance in physiological and disease-like conditions, their reversible interactions with other proteins remain modestly examined. Here, we show the development and validation of a protein nanopore for the detection and quantification of WD40 repeat protein 5 (WDR5), a chromatin-associated hub involved in epigenetic regulation of histone methylation. Our nanopore sensor is equipped with a 14-residue Win motif of mixed lineage leukemia 4 methyltransferase (MLL4<sub>Win</sub>), a WDR5 ligand. Our approach reveals a broad dynamic range of MLL4<sub>Win</sub>-WDR5 interactions and three distant subpopulations of binding events, representing three modes of protein recognition. The three binding events are confirmed as specific interactions using a weakly binding WDR5 derivative and various environmental contexts. These outcomes demonstrate the substantial sensitivity of our nanopore sensor, which can be utilized in protein analytics.

Medical subject headings