Research Article

Structure of Dual Function Iron Regulatory Protein 1 Complexed with Ferritin IRE-RNA

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Science  22 Dec 2006:
Vol. 314, Issue 5807, pp. 1903-1908
DOI: 10.1126/science.1133116

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Abstract

Iron regulatory protein 1 (IRP1) binds iron-responsive elements (IREs) in messenger RNAs (mRNAs), to repress translation or degradation, or binds an iron-sulfur cluster, to become a cytosolic aconitase enzyme. The 2.8 angstrom resolution crystal structure of the IRP1:ferritin H IRE complex shows an open protein conformation compared with that of cytosolic aconitase. The extended, L-shaped IRP1 molecule embraces the IRE stem-loop through interactions at two sites separated by ∼30 angstroms, each involving about a dozen protein:RNA bonds. Extensive conformational changes related to binding the IRE or an iron-sulfur cluster explain the alternate functions of IRP1 as an mRNA regulator or enzyme.

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