title: Substitution of a Single Amino Acid Reverses the Regiospecificity of the Baeyer-Villiger Monooxygenase PntE in the Biosynthesis of the Antibiotic Pentalenolactone.
abstract: In the biosynthesis of pentalenolactone (1), PenE and PntE, orthologous proteins from Streptomyces exfoliatus and S. arenae, respectively, catalyze the flavin-dependent Baeyer-Villiger oxidation of 1-deoxy-11-oxopentalenic acid (4) to the lactone pentalenolactone D (5), in which the less-substituted methylene carbon has migrated. By contrast, the paralogous PtlE enzyme from S. avermitilis catalyzes the oxidation of 4 to neopentalenolactone D (6), in which the more substituted methane substitution has undergone migration. We report the design and analysis of 13 single and multiple mutants of PntE mutants to identify the key amino acids that contribute to the regiospecificity of these two classes of Baeyer-Villiger monooxygenases. The L185S mutation in PntE reversed the observed regiospecificity of PntE such that all recombinant PntE mutants harboring this L185S mutation acquired the characteristic regiospecificity of PtlE, catalyzing the conversion of 4 to 6 as the major product. The recombinant PntE mutant harboring R484L exhibited reduced regiospecificity, generating a mixture of lactones containing more than 17% of 6. These in vitro results were corroborated by analysis of the complementation of the S. avermitilis ΔptlED double deletion mutant with pntE mutants, such that pntE mutants harboring L185S produced 6 as the major product, whereas complemention of the ΔptlED deletion mutant with pntE mutants carrying the R484L mutation gave 6 as more than 33% of the total lactone product mixture.
authors.affiliation: The Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), Wuhan University , Wuhan, Hubei Province 430071, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Chen
authors.affiliation: The Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), Wuhan University , Wuhan, Hubei Province 430071, China.
authors.forename: Shiwen
authors.initials: S
authors.lastname: Wu
authors.affiliation: The Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), Wuhan University , Wuhan, Hubei Province 430071, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zhu
authors.affiliation: The Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), Wuhan University , Wuhan, Hubei Province 430071, China.
authors.forename: Chengde
authors.initials: C
authors.lastname: Zhang
authors.affiliation: School of Life Science, Northeast Agricultural University , Harbin, Heilongjiang Province 150030, China.
authors.forename: Wensheng
authors.initials: W
authors.lastname: Xiang
authors.affiliation: The Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), Wuhan University , Wuhan, Hubei Province 430071, China.
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.affiliation: Laboratory of Microbial Engineering, Kitasato Institute for Life Sciences, Kitasato University , 1-15-1 Kitasato, Sagamihara, Minami-ku, Kanagawa 252-0373, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Ikeda
authors.affiliation: Department of Chemistry, Box H, Brown University , Providence, Rhode Island 02912-9108, United States.
authors.forename: David E
authors.initials: DE
authors.lastname: Cane
authors.affiliation: The Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Ministry of Education), Wuhan University , Wuhan, Hubei Province 430071, China.
authors.forename: Dongqing
authors.initials: D
authors.lastname: Zhu
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000737:chemistry; D001120:Arginine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000235:genetics; D005816:Genetic Complementation Test; D008239:Lysine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008956:Models, Chemical; D015394:Molecular Structure; D020125:Mutation, Missense; D017386:Sequence Homology, Amino Acid; D012717:Sesquiterpenes / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism; D013302:Streptomyces / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D012717:Sesquiterpenes; C017996:arenaemycin E; D001120:Arginine; D006899:Mixed Function Oxygenases; D008239:Lysine