Crystal structure of TetR triple mutant (H64K, S135L, S138I) in complex with 4-ddma-atc

Experimental Data Snapshot

  • Resolution: 2.06 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.208 

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Structural origins for selectivity and specificity in an engineered bacterial repressor-inducer pair.

Klieber, M.A.Scholz, O.Lochner, S.Gmeiner, P.Hillen, W.Muller, Y.A.

(2009) FEBS J 276: 5610-5621

  • DOI: https://doi.org/10.1111/j.1742-4658.2009.07254.x
  • Primary Citation of Related Structures:  
    3FK6, 3FK7

  • PubMed Abstract: 

    The bacterial tetracycline transcription regulation system mediated by the tetracycline repressor (TetR) is widely used to study gene expression in prokaryotes and eukaryotes. To study multiple genes in parallel, a triple mutant TetR(K(64)L(135)I(138)) has been engineered that is selectively induced by the synthetic tetracycline derivative 4-de-dimethylamino-anhydrotetracycline (4-ddma-atc) and no longer by tetracycline, the inducer of wild-type TetR. In the present study, we report the crystal structure of TetR(K(64)L(135)I(138)) in the absence and in complex with 4-ddma-atc at resolutions of 2.1 A. Analysis of the structures in light of the available binding data and previously reported TetR complexes allows for a dissection of the origins of selectivity and specificity. In all crystal structures solved to date, the ligand-binding position, as well as the positioning of the residues lining the binding site, is extremely well conserved, irrespective of the chemical nature of the ligand. Selective recognition of 4-ddma-atc is achieved through fine-tuned hydrogen-bonding constraints introduced by the His64-->Lys substitution, as well as a combination of hydrophobic effect and the removal of unfavorable electrostatic interactions through the introduction of Leu135 and Ile138.

  • Organizational Affiliation

    Department of Biology, Lehrstuhl für Biotechnik, Friedrich-Alexander University, Erlangen-Nuremberg, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Tetracycline repressor protein class B from transposon Tn10, Tetracycline repressor protein class D
A, B
208Escherichia coliMutation(s): 3 
Gene Names: tetR
Find proteins for P0ACT4 (Escherichia coli)
Explore P0ACT4 
Go to UniProtKB:  P0ACT4
Find proteins for P04483 (Escherichia coli)
Explore P04483 
Go to UniProtKB:  P04483
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupsP0ACT4P04483
Sequence Annotations
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
4DM Binding MOAD:  3FK7 Kd: 0.75 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.06 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.208 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 130.22α = 90
b = 59.38β = 97.85
c = 63.78γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
MAR345dtbdata collection
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-11-03
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2017-08-23
    Changes: Refinement description, Source and taxonomy
  • Version 1.3: 2017-11-01
    Changes: Refinement description
  • Version 1.4: 2021-11-10
    Changes: Database references, Derived calculations
  • Version 1.5: 2023-11-01
    Changes: Data collection, Refinement description