3DHZ:
reference: Structural and mutational studies of the carboxylate cluster in iron-free ribonucleotide reductase R2., Andersson ME, Hogbom M, Rinaldo-Matthis A, Blodig W, Liang Y, Persson BO, Sjoberg BM, Su XD, Nordlund P, Biochemistry. 2004 Jun 22;43(24):7966-72. PMID: 15196041

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