1A6I

TET REPRESSOR, CLASS D VARIANT

• PDB DOI: https://doi.org/10.2210/pdb1A6I/pdb

• Classification: TRANSCRIPTION REGULATION
• Organism(s): Escherichia coli
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 1998-02-25 Released: 1999-03-02 
• Deposition Author(s): Orth, P., Cordes, F., Schnappinger, D., Hillen, W., Saenger, W., Hinrichs, W.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.40 Å
• R-Value Free: 0.275 
• R-Value Work: 0.214 
• R-Value Observed: 0.214 

Literature

Conformational changes of the Tet repressor induced by tetracycline trapping.

Orth, P., Cordes, F., Schnappinger, D., Hillen, W., Saenger, W., Hinrichs, W.

(1998) J Mol Biol 279: 439-447

• PubMed: 9642048 
• DOI: https://doi.org/10.1006/jmbi.1998.1775
• Primary Citation of Related Structures:  
  1A6I


• PubMed Abstract: 
  

  The X-ray crystal structure analysis of inducer-free Tet repressor, TetR, at 2.4 A resolution identifies one of two openings of the tunnel-like binding site as the entrance for the inducer tetracycline-Mg2+, [Mg Tc]+. Recognition and binding of the inducer unleashes conformational changes leading to the induced state of TetR. In the first step, the C-terminal turn of alpha-helix 6 unwinds, thereby altering the orientation of alpha-helix 4. This different orientation of alpha-helix 4 is stabilized by a series of hydrogen bonds mediated through a chain of eight water molecules. The alpha-helix 4 connects the DNA-binding domain (alpha-helices 1 to 3) to the rigid TetR core, and thus regulates gene expression through its respective orientations.

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Organizational Affiliation: 

Institut für Kristallographie, Freie Universität Berlin, Germany.

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA,PQS (software)

Macromolecule Content

• Total Structure Weight: 24.32 kDa 
• Atom Count: 1,567 
• Modelled Residue Count: 193 
• Deposited Residue Count: 217 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
TETRACYCLINE REPRESSOR PROTEIN CLASS D	A	217	Escherichia coli	Mutation(s): 9
UniProt
Find proteins for P0ACT4 (Escherichia coli) Explore P0ACT4  Go to UniProtKB:  P0ACT4

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.40 Å
• R-Value Free: 0.275 
• R-Value Work: 0.214 
• R-Value Observed: 0.214 
• Space Group: I 4₁ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 69.81	α = 90
b = 69.81	β = 90
c = 184.95	γ = 90

Software Package:

Software Name	Purpose
X-PLOR	model building
X-PLOR	refinement
MOSFLM	data reduction
CCP4	data scaling
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 1999-03-02 
Deposition Author(s): Orth, P., Cordes, F., Schnappinger, D., Hillen, W., Saenger, W., Hinrichs, W.

Revision History  

• Version 1.0: 1999-03-02
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Derived calculations, Version format compliance
• Version 1.3: 2021-11-03
  Changes: Database references, Other
• Version 1.4: 2023-08-02
  Changes: Refinement description