2B3X: Structure Of An Orthorhombic Crystal Form Of Human Cytosolic Aconitase (Irp1)

Iron regulatory proteins (IRPs) control the translation of proteins involved in iron uptake, storage and utilization by binding to specific noncoding sequences of the corresponding mRNAs known as iron-responsive elements (IREs). This strong interaction assures proper iron homeostasis in animal cells under iron shortage. Conversely, under iron-replete conditions, IRP1 binds a [4Fe-4S] cluster and functions as cytosolic aconitase. Regulation of the balance between the two IRP1 activities is complex, and it does not depend only on iron availability. Here, we report the crystal structure of human IRP1 in its aconitase form. Comparison with known structures of homologous enzymes reveals well-conserved folds and active site environments with significantly different surface shapes and charge distributions. The specific features of human IRP1 allow us to propose a tentative model of an IRP1-IRE complex that agrees with a range of previously obtained data.
PDB ID: 2B3XDownload
MMDB ID: 37117
PDB Deposition Date: 2005/9/22
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 2.54  Å
Source Organism:
Similar Structures:
Biological Unit for 2B3X: monomeric; determined by author and by software (PQS)
Molecular Components in 2B3X
Label Count Molecule
Protein (1 molecule)
Iron-responsive Element Binding Protein 1(Gene symbol: ACO1)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB