2XRL

Tet-repressor class D T103A with doxycycline

Summary for 2XRL

• Entry DOI: 10.2210/pdb2xrl/pdb
• Related: 1A6I 1BJ0 1BJY 1BJZ 1DU7 1ORK 1QPI 2TCT 2TRT 2VKE 2VKV 2X6O 2X9D 2XB5 2XGC 2XGD 2XGE 2XPS 2XPT 2XPU 2XPV 2XPW 3ZQF 3ZQG 3ZQH 3ZQI
• Descriptor: TETRACYCLINE REPRESSOR PROTEIN CLASS D, CHLORIDE ION, (4S,4AR,5S,5AR,6R,12AS)-4-(DIMETHYLAMINO)-3,5,10,12,12A-PENTAHYDROXY-6-METHYL-1,11-DIOXO-1,4,4A,5,5A,6,11,12A-OCTAHYDROTETRACENE-2-CARBOXAMIDE, ... (5 entities in total)
• Functional Keywords: transcription, antibiotic resistance, dna-binding, helix-turn-helix
• Biological source: ESCHERICHIA COLI
• Total number of polymer chains: 1
• Total formula weight: 23797.95

Authors

Palm, G.J.,Waack, P.,Hinrichs, W. (deposition date: 2010-09-16, release date: 2011-10-05, Last modification date: 2023-12-20)

Primary citation

Palm, G.J.,Buchholz, I.,Werten, S.,Girbardt, B.,Berndt, L.,Delcea, M.,Hinrichs, W.
Thermodynamics, cooperativity and stability of the tetracycline repressor (TetR) upon tetracycline binding.
Biochim Biophys Acta Proteins Proteom, 1868:140404-140404, 2020

PubMed Abstract: Allosteric regulation of the Tet repressor (TetR) homodimer relies on tetracycline binding that abolishes the affinity for the DNA operator. Previously, interpretation of circular dichroism data called for unfolding of the α-helical DNA-binding domains in absence of binding to DNA or tetracycline. Our small angle X-ray scattering of TetR(D) in solution contradicts this unfolding as a physiological process. Instead, in the core domain crystal structures analyses show increased immobilisation of helix α9 and two C-terminal turns of helix α8 upon tetracycline binding. Tetracycline complexes of TetR(D) and four single-site alanine variants were characterised by isothermal titration calorimetry, fluorescence titration, X-ray crystal structures, and melting curves. Five crystal structures confirm that Thr103 is a key residue for the allosteric events of induction, with the T103A variant lacking induction by any tetracycline. The T103A variant shows anti-cooperative inducer binding, and a melting curve of the tetracycline complex different to TetR(D) and other variants. For the N82A variant inducer binding is clearly anti-cooperative but triggers the induced conformation.

PubMed: 32114262
DOI: 10.1016/j.bbapap.2020.140404

Experimental method

X-RAY DIFFRACTION (1.85 Å)