2FJ1

Crystal Structure Analysis of Tet Repressor (class D) in Complex with 7-Chlortetracycline-Nickel(II)

Summary for 2FJ1

• Entry DOI: 10.2210/pdb2fj1/pdb
• Related: 1QPI 2TCT 2TRT
• Descriptor: Tetracycline repressor protein class D, NICKEL (II) ION, CHLORIDE ION, ... (5 entities in total)
• Functional Keywords: transcription regulation, helix-turn-helix, metal coordination, transcription regulator
• Biological source: Escherichia coli
• Total number of polymer chains: 1
• Total formula weight: 23932.27

Authors

Orth, P.,Saenger, W.,Palm, G.J.,Hinrichs, W. (deposition date: 2005-12-30, release date: 2007-01-09, Last modification date: 2023-08-30)

Primary citation

Palm, G.J.,Lederer, T.,Orth, P.,Saenger, W.,Takahashi, M.,Hillen, W.,Hinrichs, W.
Specific binding of divalent metal ions to tetracycline and to the Tet repressor/tetracycline complex.
J.Biol.Inorg.Chem., 13:1097-1110, 2008

PubMed Abstract: Tetracyclines coordinate metal(II) ions under physiological conditions forming chelate complexes with their ketoenolate moiety at rings B and C. These metal(II) complexes are the biologically relevant molecules conferring the antibiotic character of the drug by inhibiting ribosomal protein biosynthesis in prokaryotes. The Tet repressor, TetR, is the molecular switch for tetracycline resistance determinants in gram-negative bacteria. TetR controls transcription of a gene encoding the integral membrane protein TetA, which mediates active efflux of a tetracycline-metal(II) cation, [MeTc](+), by equimolar antiport with a proton. We evaluated distinct characteristics of the metal binding by crystal structure determination of TetR/[MeTc](+) complexes and of association equilibrium constants of [MeTc](+) and TetR/[MeTc](+) complexes. Various divalent metal ions bind to the same octahedral coordination site, defined by a histidine side chain of TetR, the tetracycline, and three water molecules. Whereas association constants for [MeTc](+) vary within 3 orders of magnitude, association of the [MeTc](+) cation to TetR is very similar for all measured divalent metals. Taking intracellular cation concentrations into account, it is evident that no other metal ion can compete with Mg(2+) for TetR/[MeTc](+) complex formation.

PubMed: 18548290
DOI: 10.1007/s00775-008-0395-2

Experimental method

X-RAY DIFFRACTION (2.2 Å)