title: Deciphering Carbamoylpolyoxamic Acid Biosynthesis Reveals Unusual Acetylation Cycle Associated with Tandem Reduction and Sequential Hydroxylation.
abstract: Polyoxin, produced by Streptomcyes cacaoi var. asoensis and Streptomyces aureochromogenes, contains two non-proteinogenic amino acids, carbamoylpolyoxamic acid (CPOAA) and polyoximic acid. Although the CPOAA moiety is highly unusual, its biosynthetic logic has remained enigmatic for decades. Here, we address CPOAA biosynthesis by reconstitution of its pathway. We demonstrated that its biosynthesis is initiated by a versatile N-acetyltransferase, PolN, catalyzing L-glutamate (1) to N-acetyl glutamate (2). Remarkably, we verified that PolM, a previously annotated dehydrogenase, catalyzes an unprecedented tandem reduction of acyl-phosphate to aldehyde, and subsequently to alcohol. We also unveiled a distinctive acetylation cycle catalyzed by PolN to synthesize α-amino-δ-hydroxyvaleric acid (6). Finally, we report that PolL is capable of converting a rare sequential hydroxylation of α-amino-δ-carbamoylhydroxyvaleric acid (7) to CPOAA. PolL represents an intriguing family of Fe(II)-dependent α-ketoglutarate dioxygenase with a cupin fold. These data illustrate several novel enzymatic reactions, and also set a foundation for rational pathway engineering for polyoxin production.
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Jianzhao
authors.initials: J
authors.lastname: Qi
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Wan
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Ma
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Yuanzhen
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Gong
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Xudong
authors.initials: X
authors.lastname: Qu
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Yuhui
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China.
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.affiliation: Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China. Electronic address: wqchen@whu.edu.cn.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Chen
mesh_terms: D000107:Acetylation; D000123:Acetyltransferases / Q000378:metabolism; D055162:Biocatalysis; D049308:Dioxygenases / Q000378:metabolism; D006900:Hydroxylation; D008958:Models, Molecular; D015394:Molecular Structure; D010072:Oxamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism
chemical_list: C015053:carbamoylpolyoxamic acid; D010088:Oxidoreductases; D049308:Dioxygenases; D000123:Acetyltransferases; D010072:Oxamic Acid