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Exploring the electron transfer pathway in the oxidation of avermectin by CYP107Z13 in Streptomyces ahygroscopicus ZB01.

Li M, Zhang Y, Zhang L, Yang X, Jiang X - PLoS ONE (2014)

Bottom Line: Streptomyces ahygroscopicus ZB01 can effectively oxidize 4″-OH of avermectin to form 4″-oxo-avermectin.A putative [3Fe-4S] ferredoxin gene fd68 and two possible NADH-dependent ferredoxin reductase genes fdr18 and fdr28 were cloned from the genomic DNA of ZB01. fd68 gene disruption mutants showed no catalytic activity in oxidation of avermectin to form 4″-oxo-avermectin.Both of the two biocatalytic systems were found to be able to mediate the oxidation of avermectin to form 4″-oxo-avermectin.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.

ABSTRACT
Streptomyces ahygroscopicus ZB01 can effectively oxidize 4″-OH of avermectin to form 4″-oxo-avermectin. CYP107Z13 is responsible for this site-specific oxidation in ZB01. In the present study, we explored the electron transfer pathway in oxidation of avermectin by CYP107Z13 in ZB01. A putative [3Fe-4S] ferredoxin gene fd68 and two possible NADH-dependent ferredoxin reductase genes fdr18 and fdr28 were cloned from the genomic DNA of ZB01. fd68 gene disruption mutants showed no catalytic activity in oxidation of avermectin to form 4″-oxo-avermectin. To clarify whether FdR18 and FdR28 participate in the electron transfer during avermectin oxidation by CYP107Z13, two whole-cell biocatalytic systems were designed in E. coli BL21 (DE3), with one co-expressing CYP107Z13, Fd68 and FdR18 and the other co-expressing CYP107Z13, Fd68 and FdR28. Both of the two biocatalytic systems were found to be able to mediate the oxidation of avermectin to form 4″-oxo-avermectin. Thus, we propose an electron transfer pathway NADH→FdR18/FdR28→Fd68→CYP107Z13 for oxidation of avermectin to form 4″-oxo-avermectin in ZB01.

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Structures of the avermectin and product 4″-O-avermectin.
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pone-0098916-g001: Structures of the avermectin and product 4″-O-avermectin.

Mentions: Streptomyces spp. produces many important natural products, including many known antibiotics. Cytochrome P450 enzymes (CYP450s) are involved in these biosynthetic and biotransformation reactions [1], [2]. P450s are heme-dependent monooxygenases that catalyze the insertion of oxygen atoms from atmospheric oxygen molecules into carbon–hydrogen bonds within a diverse range of organic compounds [3]. Emamectin benzoate is a derivate of avermectin, a potent semisynthetic insecticide used to control many agriculturally important pests. Oxidation of 4″-OH into 4″-oxo of avermectin is one key reaction step in the synthesis of emamectin benzoate from avermectin [4]. Direct regiospecific chemical oxidation of the 4″-OH group in avermectin to form 4″-oxo-avermectin is precluded by the high reactivity of the 5-OH group in the molecule, necessitating a protection–deprotection strategy (Fig. 1). Avoiding these additional steps would greatly reduce the complexity of the production process along with the final cost of emamectin benzoate. CYP107Zs from Streptomyces were reported to have the capability to oxidize 4″-OH into 4″-oxo of avermectin regioselectively [5].


Exploring the electron transfer pathway in the oxidation of avermectin by CYP107Z13 in Streptomyces ahygroscopicus ZB01.

Li M, Zhang Y, Zhang L, Yang X, Jiang X - PLoS ONE (2014)

Structures of the avermectin and product 4″-O-avermectin.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048220&req=5

pone-0098916-g001: Structures of the avermectin and product 4″-O-avermectin.
Mentions: Streptomyces spp. produces many important natural products, including many known antibiotics. Cytochrome P450 enzymes (CYP450s) are involved in these biosynthetic and biotransformation reactions [1], [2]. P450s are heme-dependent monooxygenases that catalyze the insertion of oxygen atoms from atmospheric oxygen molecules into carbon–hydrogen bonds within a diverse range of organic compounds [3]. Emamectin benzoate is a derivate of avermectin, a potent semisynthetic insecticide used to control many agriculturally important pests. Oxidation of 4″-OH into 4″-oxo of avermectin is one key reaction step in the synthesis of emamectin benzoate from avermectin [4]. Direct regiospecific chemical oxidation of the 4″-OH group in avermectin to form 4″-oxo-avermectin is precluded by the high reactivity of the 5-OH group in the molecule, necessitating a protection–deprotection strategy (Fig. 1). Avoiding these additional steps would greatly reduce the complexity of the production process along with the final cost of emamectin benzoate. CYP107Zs from Streptomyces were reported to have the capability to oxidize 4″-OH into 4″-oxo of avermectin regioselectively [5].

Bottom Line: Streptomyces ahygroscopicus ZB01 can effectively oxidize 4″-OH of avermectin to form 4″-oxo-avermectin.A putative [3Fe-4S] ferredoxin gene fd68 and two possible NADH-dependent ferredoxin reductase genes fdr18 and fdr28 were cloned from the genomic DNA of ZB01. fd68 gene disruption mutants showed no catalytic activity in oxidation of avermectin to form 4″-oxo-avermectin.Both of the two biocatalytic systems were found to be able to mediate the oxidation of avermectin to form 4″-oxo-avermectin.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.

ABSTRACT
Streptomyces ahygroscopicus ZB01 can effectively oxidize 4″-OH of avermectin to form 4″-oxo-avermectin. CYP107Z13 is responsible for this site-specific oxidation in ZB01. In the present study, we explored the electron transfer pathway in oxidation of avermectin by CYP107Z13 in ZB01. A putative [3Fe-4S] ferredoxin gene fd68 and two possible NADH-dependent ferredoxin reductase genes fdr18 and fdr28 were cloned from the genomic DNA of ZB01. fd68 gene disruption mutants showed no catalytic activity in oxidation of avermectin to form 4″-oxo-avermectin. To clarify whether FdR18 and FdR28 participate in the electron transfer during avermectin oxidation by CYP107Z13, two whole-cell biocatalytic systems were designed in E. coli BL21 (DE3), with one co-expressing CYP107Z13, Fd68 and FdR18 and the other co-expressing CYP107Z13, Fd68 and FdR28. Both of the two biocatalytic systems were found to be able to mediate the oxidation of avermectin to form 4″-oxo-avermectin. Thus, we propose an electron transfer pathway NADH→FdR18/FdR28→Fd68→CYP107Z13 for oxidation of avermectin to form 4″-oxo-avermectin in ZB01.

Show MeSH