6E13:
reference: Discovery of Hydroxylase Activity for PqqB Provides a Missing Link in the Pyrroloquinoline Quinone Biosynthetic Pathway., Koehn EM, Latham JA, Armand T, Evans RL 3rd, Tu X, Wilmot CM, Iavarone AT, Klinman JP, J Am Chem Soc. 2019 Mar 13;141(10):4398-4405. doi: 10.1021/jacs.8b13453. Epub, 2019 Feb 27. PMID: 30811189

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