FIG. 5.
A comparison of the structure of the polypeptide IRP1 bound to [4Fe-4S] (c-aconitase) on the left and bound to the IRE-RNA, noncoding regulatory structure on the right. Note the large difference in structure, indicating the possibility that the redox- sensitive “switch” occurs at or before [4Fe-4S]2+ transfer from the CIA cytosolic Fe-S assembly machinery to the apo-IRP1 polypeptide. (Reproduced with permission from ref. 158). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article at www.liebertonline.com/ars).