1Q5Y:
reference: Crystal structure of the nickel-responsive transcription factor NikR., Schreiter ER, Sintchak MD, Guo Y, Chivers PT, Sauer RT, Drennan CL, Nat Struct Biol 2003 Oct;10(10):794-9. Epub 2003 Sep 14. PMID: 12970756

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