PDBsum entry 2fx0

Transcription

PDB id: 2fx0

Contents

Protein chain

179 a.a. *

Waters ×114

* Residue conservation analysis

PDB id:

2fx0

Name:

Transcription

Title:

Crystal structure of hlyiir, a hemolysin ii transcriptional regulator

Structure:

Hemolysin ii regulatory protein. Chain: a. Engineered: yes

Source:

Bacillus cereus. Organism_taxid: 1396. Strain: b771. Gene: hlyiir. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PDB file)

Resolution:

2.40Å R-factor: 0.223 R-free: 0.276

Authors:

O.V.Kovalevskiy,A.A.Lebedev,A.S.Solonin,A.A.Antson

Key ref:

O.V.Kovalevskiy et al. (2007). Crystal structure of Bacillus cereus HlyIIR, a transcriptional regulator of the gene for pore-forming toxin hemolysin II. J Mol Biol, 365, 825-834. PubMed id: 17097673 DOI: 10.1016/j.jmb.2006.10.074

Date:

03-Feb-06 Release date: 21-Feb-06

Protein chain

Q7X506  (Q7X506_BACCE) -  Hemolysin II regulatory protein from Bacillus cereus

Seq: 201 a.a.

Struc: 179 a.a.

DOI no: 10.1016/j.jmb.2006.10.074

J Mol Biol 365:825-834 (2007)

PubMed id: 17097673

Crystal structure of Bacillus cereus HlyIIR, a transcriptional regulator of the gene for pore-forming toxin hemolysin II.

O.V.Kovalevskiy, A.A.Lebedev, A.K.Surin, A.S.Solonin, A.A.Antson.

ABSTRACT

Production of Bacillus cereus and Bacillus anthracis toxins is controlled by a number of transcriptional regulators. Here we report the crystal structure of B. cereus HlyIIR, a regulator of the gene encoding the pore-forming toxin hemolysin II. We show that HlyIIR forms a tight dimer with a fold and overall architecture similar to the TetR family of repressors. A remarkable feature of the structure is a large internal cavity with a volume of 550 A(3) suggesting that the activity of HlyIIR is modulated by binding of a ligand, which triggers the toxin production. Virtual ligand library screening shows that this pocket can accommodate compounds with molecular masses of up to 400-500 Da. Based on structural data and previous biochemical evidence, we propose a model for HlyIIR interaction with the DNA.

Selected figure(s)

Figure 1.
Figure 1. The HlyIIR structure. (a) Electron density corresponding to one of the protein helices (α1) calculated with maximum likelihood weighted coefficients 2|F[o]|–|F[c]| and contoured at 1.25σ. (b) and (c) Ribbon diagrams of HlyIIR. Monomer (b) is rainbow-coloured with its N-terminal in red and C-terminal in blue. Dotted line indicates the disordered segment, which was not modelled. The biological dimer (c) is generated by the crystallographic 2-fold axis. The large internal cavity (yellow) is drawn along the van der Waals radii of cavity-forming residues. The cavity surface was calculated by SURFNET.^33 This Figure and Figure 3 and Figure 4 were prepared using CCP4MG.^34

Figure 3.
Figure 3. Ligand-binding pocket. (a) Stereo view with the cavity contoured as in Figure 1(c) and cavity-lining residues shown by sticks. The compound that gave a highest score during the AutoDock screening (NCI 23904) is shown with its carbon atoms in brown, oxygen atoms in pink and nitrogen atoms in light blue. (b) Difference electron density maps (green) corresponding to the pocket area and contoured at 3σ.

The above figures are reprinted from an Open Access publication published by Elsevier: J Mol Biol (2007, 365, 825-834) copyright 2007.