In Arabidopsis thaliana, the Sigma factor B regulator RsbQ-like family of alpha/beta hydrolases contains the strigolactone (SL) receptor DWARF14 (AtD14), the karrikin receptor KARRIKIN INSENSITIVE2 (AtKAI2), and DWARF14-LIKE2 (AtDLK2), a protein of unknown function. Despite very similar protein folds, AtD14 and AtKAI2 differ in size and architecture of their ligand binding pockets, influencing their substrate specificity. We present the 1.5 A crystal structure of AtDLK2, revealing the smallest ligand binding pocket in the protein family, bordered by two unique glycine residues. We identified a gatekeeper residue in the protein's lid domain and present a pyrrolo-quinoline-dione compound that inhibits AtDLK2's enzymatic activity.
Representative scheme of RsbQ-like structure and an image from PDBsum server
no Image
Databases
PDB-Sum
7TVW Previously Class, Architecture, Topology and Homologous superfamily - PDB-Sum server
FSSP
7TVWFold classification based on Structure-Structure alignment of Proteins - FSSP server
