2XB5

Tet repressor (class D) in complex with 7-Iodotetracycline

• PDB DOI: https://doi.org/10.2210/pdb2XB5/pdb

• Classification: TRANSCRIPTION
• Organism(s): Escherichia coli
• Expression System: Escherichia coli K-12
• Mutation(s): No 


• Deposited: 2010-04-05 Released: 2010-10-06 
• Deposition Author(s): Kisker, C., Saenger, W., Hinrichs, W.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.50 Å
• R-Value Free: 0.230 
• R-Value Work: 0.162 
• R-Value Observed: 0.168 

Literature

Structure of the Tet repressor-tetracycline complex and regulation of antibiotic resistance.

Hinrichs, W., Kisker, C., Duvel, M., Muller, A., Tovar, K., Hillen, W., Saenger, W.

(1994) Science 264: 418-420

• PubMed: 8153629 
• DOI: https://doi.org/10.1126/science.8153629
• Primary Citation of Related Structures:  
  2TRT, 2XB5


• PubMed Abstract: 
  

  The most frequently occurring resistance of Gram-negative bacteria against tetracyclines is triggered by drug recognition of the Tet repressor. This causes dissociation of the repressor-operator DNA complex and enables expression of the resistance protein TetA, which is responsible for active efflux of tetracycline. The 2.5 angstrom resolution crystal structure of the homodimeric Tet repressor complexed with tetracycline-magnesium reveals detailed drug recognition. The orientation of the operator-binding helix-turn-helix motifs of the repressor is inverted in comparison with other DNA binding proteins. The repressor-drug complex is unable to interact with DNA because the separation of the DNA binding motifs is 5 angstroms wider than usually observed.

---

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 (software)

Macromolecule Content

• Total Structure Weight: 23.87 kDa 
• Atom Count: 1,713 
• Modelled Residue Count: 207 
• Deposited Residue Count: 207 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
TETRACYCLINE REPRESSOR PROTEIN CLASS D	A	207	Escherichia coli	Mutation(s): 0
UniProt
Find proteins for P0ACT4 (Escherichia coli) Explore P0ACT4  Go to UniProtKB:  P0ACT4

Small Molecules

Ligands 3 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
I7T	B [auth A]	7-IODOTETRACYCLINE C21 H21 I N2 O7 HTASTNARVGFMKI-UVPAEMEASA-N
CL	D [auth A]	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M
MG	C [auth A]	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.50 Å
• R-Value Free: 0.230 
• R-Value Work: 0.162 
• R-Value Observed: 0.168 
• Space Group: I 4₁ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 68.86	α = 90
b = 68.86	β = 90
c = 180.94	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
MOSFLM	data reduction

Structure Validation

Entry History 

Deposition Data

• Released Date: 2010-10-06 
Deposition Author(s): Kisker, C., Saenger, W., Hinrichs, W.

Revision History  

• Version 1.0: 2010-10-06
  Type: Initial release
  
• Version 1.1: 2011-05-08
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2018-03-07
  Changes: Source and taxonomy
• Version 1.4: 2019-05-08
  Changes: Data collection, Experimental preparation
• Version 1.5: 2019-07-24
  Changes: Data collection
• Version 1.6: 2019-10-09
  Changes: Data collection, Database references, Other