Divergolides A–D from a Mangrove Endophyte Reveal an Unparalleled Plasticity in ansa‐Macrolide Biosynthesis

We report a preliminary functional and complete structural characterization of a highly unusual geldanamycin analog, natalamycin A, that was isolated from Streptomyces strain M56 recovered from a South African nest of Macrotermes natalensis termites. Bioassay-guided fractionation based on antifungal activity led to the isolation of natalamycin A, and a combination of NMR spectroscopy and X-ray crystallographic analysis, including highly-accurate quantum-chemical NMR calculations on the largest and most conformationally-flexible system to date, revealed natalamycin A’s three-dimensional solid- and solution-state structure. This structure along with the structures of related compounds isolated from the same source suggest a geldanamycin-like biosynthetic pathway with unusual post-PKS modifications.

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“…7,9,22 Another approach to ansamycin structural diversification using chain extender units has recently been reported. 23 …”

Section: Resultsmentioning

confidence: 99%

Natalamycin A, an ansamycin from a termite-associated Streptomyces sp.

et al. 2014

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“…Ding et al [62] reported divergolides A-D ( 44 – 47 ) with complex and diverse structures isolated from an endophyte Streptomyces sp. HKI0576 of the mangrove tree Bruguiera gymnorrhiza in China.…”

Section: Natural Products Produced By Mangrove Actinomycetesmentioning

confidence: 99%

Natural Products from Mangrove Actinomycetes

et al. 2014

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Mangroves are woody plants located in tropical and subtropical intertidal coastal regions. The mangrove ecosystem is becoming a hot spot for natural product discovery and bioactivity survey. Diverse mangrove actinomycetes as promising and productive sources are worth being explored and uncovered. At the time of writing, we report 73 novel compounds and 49 known compounds isolated from mangrove actinomycetes including alkaloids, benzene derivatives, cyclopentenone derivatives, dilactones, macrolides, 2-pyranones and sesquiterpenes. Attractive structures such as salinosporamides, xiamycins and novel indolocarbazoles are highlighted. Many exciting compounds have been proven as potential new antibiotics, antitumor and antiviral agents, anti-fibrotic agents and antioxidants. Furthermore, some of their biosynthetic pathways have also been revealed. This review is an attempt to consolidate and summarize the past and the latest studies on mangrove actinomycetes natural product discovery and to draw attention to their immense potential as novel and bioactive compounds for marine drugs discovery.

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“…; Ding et al . ), was obtained from strain W112, an endophyte of Camptotheca acuminate . Another new ansamycin, 5, 21‐cyclic derivative of ansalactam A, was identified from XZQH‐4.…”

Section: Resultsmentioning

confidence: 99%

“…It shares many biosynthetic characteristics with divergolide D. For example, both are naphthalenic nonaketides and have the same unusual extender unit 2‐isobutyrylmalonyl‐CoA (Ding et al . ; Wilson et al . ).…”

Section: Resultsmentioning

confidence: 99%

PCR screening reveals considerable unexploited biosynthetic potential of ansamycins and a mysterious family of AHBA-containing natural products in actinomycetes

Wang

Chen

et al. 2013

J Appl Microbiol

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Aims: Ansamycins are a family of macrolactams that are synthesized by type I polyketide synthase (PKS) using 3-amino-5-hydroxybenzoic acid (AHBA) as the starter unit. Most members of the family have strong antimicrobial, antifungal, anticancer and/or antiviral activities. We aimed to discover new ansamycins and/or other AHBA-containing natural products from actinobacteria. Methods and Results: Through PCR screening of AHBA synthase gene, we identified 26 AHBA synthase gene-positive strains from 206 plant-associated actinomycetes (five positives) and 688 marine-derived actinomycetes (21 positives), representing a positive ratio of 2Á4-3Á1%. Twenty-five ansamycins, including eight new compounds, were isolated from six AHBA synthase genepositive strains through TLC-guided fractionations followed by repeated column chromatography. To gain information about those potential ansamycin gene clusters whose products were unknown, seven strains with phylogenetically divergent AHBA synthase genes were subjected to fosmid library construction. Of the seven gene clusters we obtained, three show characteristics for typical ansamycin gene clusters, and other four, from Micromonospora spp., appear to lack the amide synthase gene, which is unusual for ansamycin biosynthesis. The gene composition of these four gene clusters suggests that they are involved in the biosynthesis of a new family of hybrid PK-NRP compounds containing AHBA substructure. Conclusions: PCR screening of AHBA synthase is an efficient approach to discover novel ansamycins and other AHBA-containing natural products. Significance and Impact of the Study: This work demonstrates that the AHBAbased screening method is a useful approach for discovering novel ansamycins and other AHBA-containing natural products from new microbial resources.

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Divergolides A–D from a Mangrove Endophyte Reveal an Unparalleled Plasticity in ansa‐Macrolide Biosynthesis

Cited by 94 publications

References 37 publications

Natalamycin A, an ansamycin from a termite-associated Streptomyces sp.

Natalamycin A, an ansamycin from a termite-associated Streptomyces sp.

Natural Products from Mangrove Actinomycetes

PCR screening reveals considerable unexploited biosynthetic potential of ansamycins and a mysterious family of AHBA-containing natural products in actinomycetes

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