1FX7

CRYSTAL STRUCTURE OF THE IRON-DEPENDENT REGULATOR (IDER) FROM MYCOBACTERIUM TUBERCULOSIS

Summary for 1FX7

• Entry DOI: 10.2210/pdb1fx7/pdb
• Related: 1b1b 1bi0 1bi1 1bi2 1bi3 1bym 1c0w 1ddn 1dpr 2dtr 2tdx
• Descriptor: IRON-DEPENDENT REPRESSOR IDER, SULFATE ION, COBALT (II) ION, ... (4 entities in total)
• Functional Keywords: ider, dtxr, iron-dependent regulator, mycobacterium tuberculosis, signaling protein
• Biological source: Mycobacterium tuberculosis
• Total number of polymer chains: 4
• Total formula weight: 103526.58

Authors

Feese, M.D.,Ingason, B.P.,Goranson-Siekierke, J.,Holmes, R.K.,Hol, W.J.G. (deposition date: 2000-09-25, release date: 2001-03-07, Last modification date: 2024-02-07)

Primary citation

Feese, M.D.,Ingason, B.P.,Goranson-Siekierke, J.,Holmes, R.K.,Hol, W.G.
Crystal structure of the iron-dependent regulator from Mycobacterium tuberculosis at 2.0-A resolution reveals the Src homology domain 3-like fold and metal binding function of the third domain.
J.Biol.Chem., 276:5959-5966, 2001

PubMed Abstract: Iron-dependent regulators are primary transcriptional regulators of virulence factors and iron scavenging systems that are important for infection by several bacterial pathogens. Here we present the 2.0-A crystal structure of the wild type iron-dependent regulator from Mycobacterium tuberculosis in its fully active holorepressor conformation. Clear, unbiased electron density for the Src homology domain 3-like third domain, which is often invisible in structures of iron-dependent regulators, was revealed by density modification and averaging. This domain is one of the rare examples of Src homology domain 3-like folds in bacterial proteins, and, in addition, displays a metal binding function by contributing two ligands, one Glu and one Gln, to the pentacoordinated cobalt atom at metal site 1. Both metal sites are fully occupied, and tightly bound water molecules at metal site 1 ("Water 1") and metal site 2 ("Water 2") are identified unambiguously. The main chain carbonyl of Leu4 makes an indirect interaction with the cobalt atom at metal site 2 via Water 2, and the adjacent residue, Val5, forms a rare gamma turn. Residues 1-3 are well ordered and make numerous interactions. These ordered solvent molecules and the conformation and interactions of the N-terminal pentapeptide thus might be important in metal-dependent activation.

PubMed: 11053439
DOI: 10.1074/jbc.M007531200

Experimental method

X-RAY DIFFRACTION (2 Å)