1L1L:
reference: The crystal structure of class II ribonucleotide reductase reveals how an allosterically regulated monomer mimics a dimer., Sintchak MD, Arjara G, Kellogg BA, Stubbe J, Drennan CL, Nat Struct Biol 2002 Apr;9(4):293-300. PMID: 11875520

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