Choi Yoo Seong, Zhang Houjin, Brunzelle Joseph S, Nair Satish K, Zhao Huimin
Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, IL 61801, USA.
Proc Natl Acad Sci U S A. 2008 May 13;105(19):6858-63. doi: 10.1073/pnas.0712073105. Epub 2008 May 5.
p-Aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here, we report the in vitro reconstitution of the AurF enzyme activity, the crystal structure of AurF in the oxidized state, and the cocrystal structure of AurF with its product pNBA. Our combined biochemical and structural analysis unequivocally indicates that AurF is a non-heme di-iron monooxygenase that catalyzes sequential oxidation of aminoarenes to nitroarenes via hydroxylamine and nitroso intermediates.
来自淡紫硫链霉菌的对氨基苯甲酸N-加氧酶（AurF）在抗生素金硫素的生物合成中，催化由对氨基苯甲酸（pABA）形成不寻常的聚酮合酶起始单元对硝基苯甲酸（pNBA）。AurF是一种金属酶，但其天然酶活性尚未在体外得到证实，其催化机制也不清楚。此外，辅因子的性质仍存在争议。在此，我们报道了AurF酶活性的体外重构、氧化态AurF的晶体结构以及AurF与其产物pNBA的共晶体结构。我们结合生化和结构分析明确表明，AurF是一种非血红素双铁单加氧酶，它通过羟胺和亚硝基中间体催化氨基芳烃顺序氧化为硝基芳烃。
