Function
ACO1, or IRP1, is a bifunctional protein that functions as an iron-responsive element (IRE)-binding protein involved in the control of iron metabolism by binding mRNA to repress translation or degradation. It functions also as the cytoplasmic isoform of aconitase. Aconitases are iron-sulfur proteins that require a 4Fe-4S cluster for their enzymatic activity, in which they catalyze conversion of citrate to isocitrate. This structure was based on x-ray crystal diffraction. The resolution was 2.80 Å. This protein was harvested from the species Oryctolagus cuniculus, or more commonly known as a rabbit. This protein has a couple conformational changes associated with it to explain the alternative functions as either mRNA regulator or as an enzyme. This informations was obtained from the RCSB protein data bank website.
IRP2 is less abundant than IRP1 in most cells. The strongest expression is in intestine and brain. Relative to IRP1, IRP2 has a 73-amino acid insertion, and this insertion mediates the IRP2 degradation in iron-replete cells. IRP2 is regulated by the F-Box FBXL5 which activate the ubiquitination and then the degradation of IRP2. IRP2 has no aconitase activity.
Read more about this topic: Iron-responsive Element-binding Protein
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