1PBB:
reference: Crystal structures of wild-type p-hydroxybenzoate hydroxylase complexed with 4-aminobenzoate,2,4-dihydroxybenzoate, and 2-hydroxy-4-aminobenzoate and of the Tyr222Ala mutant complexed with 2-hydroxy-4-aminobenzoate. Evidence for a proton channel and a new binding mode of the flavin ring., Schreuder HA, Mattevi A, Obmolova G, Kalk KH, Hol WG, van der Bolt FJ, van Berkel WJ, Biochemistry 1994 Aug 23;33(33):10161-70. PMID: 7520279

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