1b1b image
Deposition Date 1998-11-19
Release Date 1999-12-03
Last Version Date 2023-12-27
Entry Detail
PDB ID:
1B1B
Title:
IRON DEPENDENT REGULATOR
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.60 Å
R-Value Free:
0.36
R-Value Work:
0.28
R-Value Observed:
0.28
Space Group:
P 62
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:PROTEIN (IRON DEPENDENT REGULATOR)
Chain IDs:A
Chain Length:140
Number of Molecules:1
Biological Source:Mycobacterium tuberculosis
Primary Citation
Crystal structure of the iron-dependent regulator (IdeR) from Mycobacterium tuberculosis shows both metal binding sites fully occupied.
J.Mol.Biol. 285 1145 1156 (1999)
PMID: 9887269 DOI: 10.1006/jmbi.1998.2339

Abstact

Iron-dependent regulators are a family of metal-activated DNA binding proteins found in several Gram-positive bacteria. These proteins are negative regulators of virulence factors and of proteins of bacterial iron-uptake systems. In this study we present the crystal structure of the iron-dependent regulator (IdeR) from Mycobacterium tuberculosis, the causative agent of tuberculosis. The protein crystallizes in the hexagonal space group P62 with unit cell dimensions a=b=92.6 A, c=63.2 A. The current model comprises the N-terminal DNA-binding domain (residues 1-73) and the dimerization domain (residues 74-140), while the third domain (residues 141-230) is too disordered to be included. The molecule lies on a crystallographic 2-fold axis that generates the functional dimer. The overall structure of the monomer shares many features with the homologous regulator, diphtheria toxin repressor (DtxR) from Corynebacterium diphtheriae. The IdeR structure in complex with Zinc reported here is, however, the first wild-type repressor structure with both metal binding sites fully occupied. This crystal structure reveals that both Met10 and most probably the Sgamma of Cys102 are ligands of the second metal binding site. In addition, there are important changes in the tertiary structure between apo-DtxR and holo-IdeR bringing the putative DNA binding helices closer together in the holo repressor. The mechanism by which metal binding may cause these structural changes between apo and holo wild-type repressor is discussed.

Legend

Protein

Chemical

Disease

Primary Citation of related structures