1FX7:
reference: Crystal structure of the iron-dependent regulator from Mycobacterium tuberculosis at 2.0-A resolution reveals the Src homology domain 3-like fold and metal binding function of the third domain., Feese MD, Ingason BP, Goranson-Siekierke J, Holmes RK, Hol WG, J Biol Chem 2001 Feb 23;276(8):5959-66. PMID: 11053439

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