Milbemycins .ALPHA.11, .ALPHA.l2, .ALPHA.13, .ALPHA.14, and .ALPHA.15: A new family of milbemycins from Streptomyces hygroscopicus subsp. aureolacrimosus. Taxonomy, fermentation, isolation, structure elucidation and biological properties.

Takahashi, Shuji; Miyaoka, Hiroko; Tanaka, Keiji; Enokita, Ryuzo; Okazaki, Takao

doi:10.7164/antibiotics.46.1364

Cited by 16 publications

(7 citation statements)

References 9 publications

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“…Meilingmycin A/milbemycin ␣11 is the main product in S. nanchangensis NS3226, whereas milbemycin ␤1/meilingmycin D is the major component in milbemycin producer Streptomyces hygroscopicus subsp. aureolacrimosus SANK 60286 (34).…”

Section: Resultsmentioning

confidence: 99%

Cloning of Separate Meilingmycin Biosynthesis Gene Clusters by Use of Acyltransferase-Ketoreductase Didomain PCR Amplification

Sun

Liu

et al. 2010

Appl Environ Microbiol

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Five meilingmycins, A to E, with A as the major component, were isolated from Streptomyces nanchangensis NS3226. Through nuclear magnetic resonance (NMR) characterization, meilingmycins A to E proved to be identical to reported milbemycins ␣11, ␣13, ␣14, ␤1, and ␤9, respectively. Sequencing of a previously cloned 103-kb region identified three modular type I polyketide synthase genes putatively encoding the last 11 elongation steps, three modification proteins, and one transcriptional regulatory protein for meilingmycin biosynthesis. However, the expected loading module and the first two elongation modules were missing. In meilingmycin, the presence of a methyl group at C-24 and a hydroxyl group at C-25 suggests that the elongation module 1 contains a methylmalonyl-coenzyme A (CoA)-specific acyltransferase (ATp) domain and a ketoreductase (KR) domain. Based on the conserved motifs of the ATp and KR domains, a pair of primers was designed for PCR amplification, and a 1.40-kb expected fragment was amplified, whose sequence shows significant homology with the elongation module 1 of the aveA1-encoded enzyme AVES1. A polyketide synthase (PKS) gene encoding one loading and two elongation modules, with a downstream C-5-O-methyltransferase gene, meiD, was subsequently localized 55 kb apart from the previously sequenced region, and its deletion abolishes meilingmycin production. A series of deletions within the 55-kb intercluster region rules out its involvement in meilingmycin biosynthesis. Furthermore, gene deletion of meiD eliminates meilingmycins D and E, with methyls at C-5. Our work provides a more specific strategy for the cloning of modular type I PKS gene clusters. The cloning of the meilingmycin gene clusters paves the way for its pathway engineering.Backbones of macrolides (e.g., erythromycin), polyenes (e.g., candicidin), polyethers (e.g., nanchangmycin), ansamycins (e.g., ansamitocin), and the polyketide portion of peptidepolyketide hybrids (e.g., oxazolomycin) are usually biosynthesized from simple carboxylic acids by the modular polyketide synthases (PKSs; type I PKSs) (6,8,30,37,38). Type I PKSs are multifunctional polypeptides and divided into modules, and each module is responsible for the incorporation of one carboxylic acid into the polyketide backbone. A minimal module is usually an ordered array of ketosynthase (KS), acyltransferase (AT), and acyl carrier protein (ACP) domains, with the ␤-carbonyl group unreduced in its thioester products (16). KS catalyzes the carbon-carbon bond formation between the incoming extender unit and polyketide intermediate by the Claisen condensation, whereas ACP serves as the carrier for both the incoming extender units and the extended chains using a covalently bound phosphopantetheine arm. Selection and loading of extender acyl units is executed by acyltransferase (AT) domains, which contributes to the structural diversity of polyketides by recruiting different extender units such as acetate-derived malonyl coenzyme A (CoA), propionate-derived methylmalonyl-CoA, and g...

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Section: Resultsmentioning

confidence: 99%

Cloning of Separate Meilingmycin Biosynthesis Gene Clusters by Use of Acyltransferase-Ketoreductase Didomain PCR Amplification

Sun

Liu

et al. 2010

Appl Environ Microbiol

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“…Meilingmycin differs from avermectin in having no α-L-oleandrose attached at position 13 of the macrolide ring (implication of an extra or functional dehydratase and enoyl reductase domains for step 13) but has an isopantenoic acid moiety at position 4, which is probably derived from valine. The difference in the side group at position 25 probably reflects the flexibility of the starter unit in avermectin biosynthesis. ) resembles milbemycin α11 (Takahashi et al , 1993 ) and has a similar aglycone and antiparasitic activity as avermectin (Fig. 2b; Burg et al , 1979 ).…”

Section: Introductionmentioning

confidence: 94%

‘Streptomyces nanchangensis’, a producer of the insecticidal polyether antibiotic nanchangmycin and the antiparasitic macrolide meilingmycin, contains multiple polyketide gene clusters

et al. 2002

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Several independent gene clusters containing varying lengths of type I polyketide synthase genes were isolated from ' Streptomyces nanchangensis ' NS3226, a producer of nanchangmycin and meilingmycin. The former is a polyether compound similar to dianemycin and the latter is a macrolide compound similar to milbemycin, which shares the same macrolide ring as avermectin but has different side groups. Clusters A-H spanned about 133, 132, 104, 174, 122, 54, 37 and 59 kb, respectively. Two systems were developed for functional analysis of the gene clusters by gene disruption or replacement. (1) Streptomyces phage φC31 and its derived vectors can infect and lysogenize this strain. (2) pSET152, an Escherichia coli plasmid with φC31 attP site, and pHZ1358, a Streptomyces-Escherichia coli shuttle cosmid vector, both carrying oriT from RP4, can be mobilized from E. coli into NS3226 by conjugation. pHZ1358 was shown to be generally useful for generating mutant strains by gene disruption and replacement in NS3226 as well as in several other Streptomyces strains. A region in cluster A (" 133 kb) seemed to be involved in nanchangmycin production because replacement of several DNA fragments in this region by an apramycin resistance gene [aac3(IV)] gave rise to nanchangmycin non-producing mutants.

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“…The synthesis of the macrolides by polyketide synthetases is similar to the synthesis of long chain fatty acids [1]. During their synthesis macrolides and fatty acid compete for the same acyl-CoA …”

Section: May 2010mentioning

confidence: 99%

“…It possesses a 16-membered macrolide, which owns the same structure as that in avermectin and milbenycin, with the exception of a different side chain. Meiligmycin is comprised of several components, in which MB1 is the major component, the structure of which is the identical with milbemycin α 11 reported elsewhere [1]. Generally, it accounts for 40% of the whole ingredients.…”

Section: Introductionmentioning

confidence: 98%

Regulation of meilingmycin in Streptomyces nanchangensis: Effect of ammonium ion

Wang

Zhuang

Wang

et al. 2010

Korean J. Chem. Eng.

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Effects of different ammonium sulfate concentrations on meilingmycin biosynthesis were studied in this research. The results show that a lower concentration of ammonium ions stimulates the biosynthesis of meilingmycin, while a concentration higher than 5 mmol/L inhibits the mycelial growth and the biosynthesis of the products. However, increased sugar consumption rate with the elevated concentration of ammonium sulfate was observed during the fermentation process. On this basis, six enzymes, which are responsible for the meilingmycin biosynthesis and the glucose metabolism, were measured and analyzed during the bioprocess. The results suggest that glucose-6-phosphate dehydrogenase, citrate synthase, succinate dehydrogenase and fatty acid synthase are stimulated by higher concentration of ammonium ions, while valine dehydrogenase and methylmalonyl-CoA carboxyltransferase are inhibited. From the results it follows that the precursor supply was restricted with the higher concentration of ammonium ions, which results in the lower production of meilingmycin. Thus, the strategy of maintaining a low level of FAS activity is a critical factor for high yield of meilingmycin.

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Milbemycins .ALPHA.11, .ALPHA.l2, .ALPHA.13, .ALPHA.14, and .ALPHA.15: A new family of milbemycins from Streptomyces hygroscopicus subsp. aureolacrimosus. Taxonomy, fermentation, isolation, structure elucidation and biological properties.

Cited by 16 publications

References 9 publications

Cloning of Separate Meilingmycin Biosynthesis Gene Clusters by Use of Acyltransferase-Ketoreductase Didomain PCR Amplification

Cloning of Separate Meilingmycin Biosynthesis Gene Clusters by Use of Acyltransferase-Ketoreductase Didomain PCR Amplification

‘Streptomyces nanchangensis’, a producer of the insecticidal polyether antibiotic nanchangmycin and the antiparasitic macrolide meilingmycin, contains multiple polyketide gene clusters

Regulation of meilingmycin in Streptomyces nanchangensis: Effect of ammonium ion

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