9DT3

Crystal structure of the engineered sulfonylurea repressor EsR (L11-C6), bound to ethametsulfuron-methyl

Summary for 9DT3

• Entry DOI: 10.2210/pdb9dt3/pdb
• Descriptor: Sulfonylurea repressor EsR (L11-C6), methyl 2-[[4-ethoxy-6-(methylamino)-1,3,5-triazin-2-yl]carbamoylsulfamoyl]benzoate (3 entities in total)
• Functional Keywords: repressor, transcription, tetr, dna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 4
• Total formula weight: 94339.48

Authors

Schreiter, E.R.,Leija, C.,Kakani, N.K.,McBride, K.E.,Looger, L.L. (deposition date: 2024-09-30, release date: 2025-10-08, Last modification date: 2026-06-24)

Primary citation

McBride, K.E.,Kakani, N.K.,Bozhanova, N.G.,Fang, J.,Lowe, K.,Leija, C.,McGonigle, B.,Schreiter, E.R.,Hermanson, F.,Chan, M.,Arling, M.,Wang, N.,Cho, H.J.,Richey, C.,Hoerster, G.,Marvin, J.S.,Lenderts, B.,McReynolds, M.R.,Hastings, C.,Madrigal, A.,Falco, S.C.,Lassner, M.W.,Anand, A.,Gordon-Kamm, W.,Looger, L.L.
Design and evolution of the tetracycline repressor into sulfonylurea herbicide-responsive gene switches for field crops.
Nat Commun, 2026

PubMed Abstract: Chemically inducible expression systems enable transgene expression regulation in response to external small molecules. Tetracycline repressor (TetR)-based gene switches work in plants, but antibiotics are neither approved nor advisable for crop use. Here we report engineering of TetR mutants that respond to approved sulfonylurea (SU) herbicides instead of antibiotics. Designed variants show low-nanomolar EC values for ethametsulfuron-methyl (Es) or chlorsulfuron and tightly bind the Tet operator sequence, but only in the absence of corresponding SUs. Crystal structures of two repressors in complex with their respective SU ligands reveal extensive interactions explaining their strong binding. The Es repressor-based gene switch is introduced into tobacco, soybean, maize, rice, and Arabidopsis, and robust reporter gene activation is observed upon herbicide application. Addition of a repressor-regulated siRNA targeting the repressor transcript increases the magnitude and spatial distribution of the response following herbicide treatment and results in a partially bistable gene switch. The SU repressors also function well in mammalian cell culture and may enable regulation of additional genes in conjunction with TetR.

PubMed: 42259793
DOI: 10.1038/s41467-026-73848-w

Experimental method

X-RAY DIFFRACTION (2.8 Å)