Structure of a Dinuclear Iron Cluster-Containing 尾-Hydroxylase Active in Antibiotic Biosynthesis

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• 作者：Thomas M. Makris ; Cory J. Knoot ; Carrie M. Wilmot ; John D. Lipscomb
• 刊名：Biochemistry
• 出版年：2013
• 出版时间：September 24, 2013
• 年：2013
• 卷：52
• 期：38
• 页码：6662-6671
• 全文大小：541K
• 年卷期：v.52,no.38(September 24, 2013)
• ISSN：1520-4995

文摘

A family of dinuclear iron cluster-containing oxygenases that catalyze 尾-hydroxylation tailoring reactions in natural product biosynthesis by nonribosomal peptide synthetase (NRPS) systems was recently described [Makris, T. M., Chakrabarti, M., M眉nck, E., and Lipscomb, J. D. (2010) Proc. Natl. Acad. Sci. U.S.A. 107, 15391鈥?5396]. Here, the 2.17 脜 X-ray crystal structure of the archetypal enzyme from the family, CmlA, is reported. CmlA catalyzes 尾-hydroxylation of l-p-aminophenylalanine during chloramphenicol biosynthesis. The fold of the N-terminal domain of CmlA is unlike any previously reported, but the C-terminal domain has the 伪尾尾伪 fold of the metallo-尾-lactamase (MBL) superfamily. The diiron cluster bound in the C-terminal domain is coordinated by an acetate, three His residues, two Asp residues, one Glu residue, and a bridging oxo moiety. One of the Asp ligands forms an unusual monodentate bridge. No other oxygen-activating diiron enzyme utilizes this ligation or the MBL protein fold. The N-terminal domain facilitates dimerization, but using computational docking and a sequence-based structural comparison to homologues, we hypothesize that it likely serves additional roles in NRPS recognition and the regulation of O₂ activation.