Faculty Opinions recommendation of Iterative chain elongation by a pikromycin monomodular polyketide synthase.

2003 ◽  
Author(s):  
Ben Shen
Keyword(s):  
Polyketide Synthase ◽  
Chain Elongation

Iterative Chain Elongation by a Pikromycin Monomodular Polyketide Synthase

2003 ◽  
Vol 125 (16) ◽  
pp. 4682-4683 ◽  
Author(s):  
Brian J. Beck ◽  
Courtney C. Aldrich ◽  
Robert A. Fecik ◽  
Kevin A. Reynolds ◽  
David H. Sherman
Keyword(s):  
Polyketide Synthase ◽  
Chain Elongation

scholarly journals Evidence for an iterative module in chain elongation on the azalomycin polyketide synthase

2016 ◽  
Vol 12 ◽  
pp. 2164-2172 ◽  
Author(s):  
Hui Hong ◽  
Yuhui Sun ◽  
Yongjun Zhou ◽  
Emily Stephens ◽  
Markiyan Samborskyy ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Polyketide Synthase ◽  
Strong Support ◽  
Artificial Chromosome ◽  
Chain Extension ◽  
Chain Elongation ◽  
Starter Unit ◽  
Polyketide Chain ◽  
Streptomyces Olivaceus ◽  
Streptomyces Malaysiensis

The assembly-line synthases that produce bacterial polyketide natural products follow a modular paradigm in which each round of chain extension is catalysed by a different set or module of enzymes. Examples of deviation from this paradigm, in which a module catalyses either multiple extensions or none are of interest from both a mechanistic and an evolutionary viewpoint. We present evidence that in the biosynthesis of the 36-membered macrocyclic aminopolyol lactones (marginolactones) azalomycin and kanchanamycin, isolated respectively from Streptomyces malaysiensis DSM4137 and Streptomyces olivaceus Tü4018, the first extension module catalyses both the first and second cycles of polyketide chain extension. To confirm the integrity of the azl gene cluster, it was cloned intact on a bacterial artificial chromosome and transplanted into the heterologous host strain Streptomyces lividans, which does not possess the genes for marginolactone production. When furnished with 4-guanidinobutyramide, a specific precursor of the azalomycin starter unit, the recombinant S. lividans produced azalomycin, showing that the polyketide synthase genes in the sequenced cluster are sufficient to accomplish formation of the full-length polyketide chain. This provides strong support for module iteration in the azalomycin and kanchanamycin biosynthetic pathways. In contrast, re-sequencing of the gene cluster for biosynthesis of the polyketide β-lactone ebelactone in Streptomyces aburaviensis has shown that, contrary to a recently-published proposal, the ebelactone polyketide synthase faithfully follows the colinear modular paradigm.

scholarly journals Elucidating the mechanism of fluorinated extender unit loading for improved production of fluorine-containing polyketides

2017 ◽  
Vol 114 (5) ◽  
pp. E660-E668 ◽  
Author(s):  
Omer Ad ◽  
Benjamin W. Thuronyi ◽  
Michelle C. Y. Chang
Keyword(s):  
Polyketide Synthase ◽  
Acyl Carrier Protein ◽  
Type System ◽  
Large Family ◽  
Product Yield ◽  
Building Blocks ◽  
Chain Extension ◽  
Chain Elongation ◽  
Single Chain ◽  
Extender Unit

Polyketides are a large family of bioactive natural products synthesized by polyketide synthase (PKS) enzyme complexes predominantly from acetate and propionate. Given the structural diversity of compounds produced using these two simple building blocks, there has been longstanding interest in engineering the incorporation of alternative extender units. We have been investigating the mechanism of fluorinated monomer insertion by three of the six different modules of the PKS involved in erythromycin biosynthesis (6-deoxyerythronolide B synthase, DEBS) to begin understanding the contribution of different steps, such as enzyme acylation, transacylation, C–C bond formation, and chain transfer, to the overall selectivity and efficiency of this process. In these studies, we observe that inactivation of acis-acyltransferase (AT) domain to circumvent its native extender unit preference leads concurrently to a change of mechanism in which chain extension with fluorine-substituted extender units switches largely to an acyl carrier protein (ACP)-independent mode. This result suggests that the covalent linkage between the growing polyketide chain and the enzyme is lost in these cases, which would limit efficient chain elongation after insertion of a fluorinated monomer. However, use of a standalonetrans-acting AT to complement modules with catalytically deficient AT domains leads to enzyme acylation with the fluoromalonyl-CoA extender unit. Formation of the canonical ACP-linked intermediate with fluoromalonyl-CoA allows insertion of fluorinated extender units at 43% of the yield of the wild-type system while also amplifying product yield in single chain-extension experiments and enabling multiple chain extensions to form multiply fluorinated products.

scholarly journals Reconstitution of the FK228 Biosynthetic Pathway Reveals Cross Talk between Modular Polyketide Synthases and Fatty Acid Synthase

2010 ◽  
Vol 77 (4) ◽  
pp. 1501-1507 ◽  
Author(s):  
Shane R. Wesener ◽  
Vishwakanth Y. Potharla ◽  
Yi-Qiang Cheng
Keyword(s):  
Fatty Acid ◽  
Cross Talk ◽  
Biosynthetic Pathway ◽  
Fatty Acid Synthase ◽  
Polyketide Synthase ◽  
Fatty Acid Biosynthesis ◽  
Chain Elongation ◽  
E Coli ◽  
Genetic Components ◽  
Polyketide Chain

ABSTRACTFunctional cross talk between fatty acid biosynthesis and secondary metabolism has been discovered in several cases in microorganisms; none of them, however, involves a modular biosynthetic enzyme. Previously, we reported a hybrid modular nonribosomal peptide synthetase (NRPS)-polyketide synthase (PKS) pathway for the biosynthesis of FK228 anticancer depsipeptide inChromobacterium violaceumstrain 968. This pathway contains two PKS modules on the DepBC enzymes that lack a functional acyltransferase (AT) domain, and no apparent AT-encoding gene exists within the gene cluster or its vicinity. We report here that, through reconstitution of the FK228 biosynthetic pathway inEscherichia colicells, two essential genes,fabD1andfabD2, both encoding a putative malonyl coenzyme A (CoA) acyltransferase component of the fatty acid synthase complex, are positively identified to be involved in FK228 biosynthesis. Either gene product appears sufficient to complement the AT-less PKS modules on DepBC for polyketide chain elongation. Concurrently, a gene (sfp) encoding a putative Sfp-type phosphopantetheinyltransferase was identified to be necessary for FK228 biosynthesis as well. Most interestingly, engineeredE. colistrains carrying variable genetic components produced significant levels of FK228 under both aerobic and anaerobic cultivation conditions. Discovery of thetranscomplementation of modular PKSs by housekeeping ATs reveals natural product biosynthesis diversity. Moreover, demonstration of anaerobic production of FK228 by an engineered facultative bacterial strain validates our effort toward the engineering of novel tumor-targeting bioagents.

scholarly journals Identification and Heterologous Expression of the Kendomycin B Biosynthetic Gene Cluster from Verrucosispora sp. SCSIO 07399

Marine Drugs ◽  
2021 ◽  
Vol 19 (12) ◽  
pp. 673
Author(s):  
Jiang Chen ◽  
Shanwen Zhang ◽  
Yingying Chen ◽  
Xinpeng Tian ◽  
Yucheng Gu ◽  
...  
Keyword(s):  
Heterologous Expression ◽  
Gene Cluster ◽  
Polyketide Synthase ◽  
Regulatory Gene ◽  
Biosynthetic Gene Cluster ◽  
Chain Elongation ◽  
Type I ◽  
Biosynthetic Gene ◽  
Type Iii Polyketide Synthase ◽  
Type Iii

Verrucosispora sp. SCSIO 07399, a rare marine-derived actinomycete, produces a set of ansamycin-like polyketides kendomycin B–D (1–3) which possess potent antibacterial activities and moderate tumor cytotoxicity. Structurally, kendomycin B–D contain a unique aliphatic macrocyclic ansa scaffold in which the highly substituted pyran ring is connected to the quinone moiety. In this work, a type I/type III polyketide synthase (PKS) hybrid biosynthetic gene cluster coding for assembly of kendomycin B (kmy), and covering 33 open reading frames, was identified from Verrucosispora sp. SCSIO 07399. The kmy cluster was found to be essential for kendomycin B biosynthesis as verified by gene disruption and heterologous expression. Correspondingly, a biosynthetic pathway was proposed based on bioinformatics, cluster alignments, and previous research. Additionally, the role of type III PKS for generating the precursor unit 3,5-dihydroxybenzoic acid (3,5-DHBA) was demonstrated by chemical complementation, and type I PKS executed the polyketide chain elongation. The kmy cluster was found to contain a positive regulatory gene kmy4 whose regulatory effect was identified using real-time quantitative PCR (RT-qPCR). These advances shed important new insights into kendomycin B biosynthesis and help to set the foundation for further research aimed at understanding and exploiting the carbacylic ansa scaffold.

The Structure and Rearrangements of a Complete Polyketide Synthase Module During its Catalytic Cycle

Planta Medica ◽  
2013 ◽  
Vol 79 (10) ◽  
Author(s):  
DH Sherman ◽  
G Skiniotis ◽  
JL Smith ◽  
K Håkansson ◽  
S Dutta ◽  
...  
Keyword(s):  
Polyketide Synthase ◽  
Catalytic Cycle

Unravelling a microbial synergy to boost caproate production via carboxylates chain elongation with ethanol

2019 ◽  
Vol 26 (2) ◽  
pp. 63-71
Author(s):  
Ling Leng ◽  
Ying Wang ◽  
Peixian Yang ◽  
Takashi Narihiro ◽  
Masaru Konishi Nobu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Microbial Consortia ◽  
Chain Elongation ◽  
Desulfovibrio Vulgaris ◽  
Rrna Gene ◽  
Selective Enrichment ◽  
Microbial Network ◽  
Cost Efficient ◽  
Rrna Gene Sequencing

Chain elongation of volatile fatty acids for medium chain fatty acids production (e.g. caproate) is an attractive approach to treat wastewater anaerobically and recover resource simultaneously. Undefined microbial consortia can be tailored to achieve chain elongation process with selective enrichment from anaerobic digestion sludge, which has advantages over pure culture approach for cost-efficient application. Whilst the metabolic pathway of the dominant caproate producer, Clostridium kluyveri, has been annotated, the role of other coexisting abundant microbiomes remained unclear. To this end, an ethanol-acetate fermentation inoculated with fresh digestion sludge at optimal conditions was conducted. Also, physiological study, thermodynamics and 16 S rRNA gene sequencing to elucidate the biological process by linking the system performance and dominant microbiomes were integrated. Results revealed a possible synergistic network in which C. kluyveri and three co-dominant species, Desulfovibrio vulgaris, Fusobacterium varium and Acetoanaerobium sticklandii coexisted. D. vulgaris and A. sticklandii (F. varium) were likely to boost the carboxylates chain elongation by stimulating ethanol oxidation and butyrate production through a syntrophic partnership with hydrogen (H2) serving as an electron messenger. This study unveils a synergistic microbial network to boost caproate production in mixed culture carboxylates chain elongation.

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