The bifunctional iron-responsive element binding protein/cytosolic aconitase: the role of active-site residues in ligand binding and regulation.
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Philpott CC, Klausner RD, Rouault TA
The bifunctional iron-responsive element binding protein/cytosolic aconitase: the role of active-site residues in ligand binding and regulation.
Proc Natl Acad Sci U S A. 1994 Jul 19;91(15):7321-5.
- PubMed ID
- 8041788 [ View in PubMed]
- Abstract
The iron-responsive element binding protein/cytosolic aconitase functions as either an RNA binding protein that regulates the uptake, sequestration, and utilization of iron or an enzyme that interconverts citrate and isocitrate. These mutually exclusive functions are regulated by changes in cellular iron levels. By site-directed mutagenesis we show that (i) ligation of a [4Fe-4S] cluster is necessary to inactivate RNA binding and activate enzyme function in vivo, (ii) three of four arginine residues of the aconitase active site participate in RNA binding, and (iii) aconitase activity is not required for iron-mediated regulation of RNA binding.