3N1Z:
reference: Active site threonine facilitates proton transfer during dioxygen activation at the diiron center of toluene/o-xylene monooxygenase hydroxylase., Song WJ, McCormick MS, Behan RK, Sazinsky MH, Jiang W, Lin J, Krebs C, Lippard SJ, J Am Chem Soc. 2010 Oct 6;132(39):13582-5. PMID: 20839885

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