Analysis of genes involved in biosynthesis of coronafacic. We now show that the action of the entire assembly line is synchronized by a previously unrecognized turnstile mechanism that prevents the ketosynthase. Polyketide biosynthesis beyond the current paradigms shen 287. Engineered biosynthesis of a novel amidated polyketide, using. They are characterized by a phthalide and phthalimidine skeleton, respectively. Following each condensation reaction, the new betaketo group may be reduced, dehydrated, and reduced again. Polyketide biosynthesis is catalyzed by polyketide synthases pkss. Gregatin a 1 is a fungal polyketide featuring an alkylated furanone core, but the biosynthetic mechanism to furnish the intriguing molecular skeleton has yet to be elucidated. These biomolecules are synthesized from simple building blocks such as acetyl coenzyme a acetylcoa, propionylcoa, malonylcoa, and methylmalonylcoa through the action of large modular megasynthases called pkss. Vinylogous dehydration by a polyketide dehydratase domain. Structure and function of polyketide biosynthetic enzymes. Understanding the biochemistry of tetracycline pkss is an important step toward the rational and combinatorial manipulation of tetracycline biosynthesis. The starter unit used in the biosynthesis of daunorubicin is propionyl coenzyme a coa rather than acetylcoa, which is used in the production of most of the bacterial aromatic polyketides studied to date.
Type ii pkss are multienzyme complexes that carry a single set of iteratively used activities and consist of several monofunctional proteins for the synthesis of aromatic polyketides, such as daunorubicin and. Biosynthesis of the pseudomonas polyketide coronafacic acid. Polyketides, the ubiquitous products of secondary metabolism in microorganisms, are made by a process resembling fatty acid biosynthesis that allows the suppression of reduction or dehydration reactions at specific biosynthetic steps, giving rise to a wide range of often medically useful products. Request pdf chapter 1 introduction to polyketide biosynthesis even among natural productderived medicines, the polyketides stand out. Functional and structural analysis of programmed c. A hostvector system for analysis and manipulation of rifamycin polyketide biosynthesis in amycolatopsis mediterranei zhihao hu 1, daniel hunziker 1, c. This chapter discusses the logic of biosynthetic polyketide assembly. From a series of feeding experiments using clabeled precursors we could outline t chemical biology in obc biosynthesis.
Townsend1,3, 1department of chemistry, johns hopkins university, baltimore, md 21218, usa. Oxytetracycline biosynthesis journal of biological chemistry. The shikimic acid pathway and polyketide biosynthesis. The combinatorial biosynthesis of unnatural products with polyketides chuanbo zhang 0 1 2 di ke 0 1 2 yuejiao duan 0 1 2 wenyu lu 0 1 2 0 collaborative innovation center of chemical science and engineering tianjin, tianjin 300350, china 1 key laboratory of system bioengineering, ministry of education, tianjin 300350, china 2 school of chemical engineering and technology, tianjin. Overview of polyketides and polyketide biosynthesis youtube. Richard hutchinson 1, chaitan khosla 1 view affiliations hide affiliations. Vederas published by springer berlin heidelberg isbn. Reconstitution of polyketide biosynthesis in heterologous hosts demands that large multienzyme assemblies be functionally expressed, their posttranslational modification needs be adequately met, their substrates be available in vivo in reasonable quantities, and the producer cell be protected against the toxicity of the biosynthetic products.
Polyketide synthases pkss are a family of multidomain enzymes or enzyme complexes that produce polyketides, a large class of secondary metabolites, in bacteria, fungi, plants, and a few animal lineages. Heterocycles are abundant structural elements of natural products from all classes and they often contribute significantly to their biological activity. Polyketides represent an array of often structurally complex natural products produced by diverse organisms, many of which are pharmacologically valuable. These examples serve as an inspiration for searching novel polyketide synthases to give new insights into polyketide biosynthesis and to provide new opportunities for combinatorial biosynthesis. Examples include the naphthoate of neocarzinostatin and the hexasubstituted orsellinate of calicheamicin, and their respective bgcs have additional pkss and accessory proteins to biosynthesize these moieties 4,11. Functional and structural analysis of programmed cmethylation in the biosynthesis of the fungal polyketide citrinin philip a. Biosynthesis of complex polyketides in a metabolically. The genes involved in cfa biosynthesis are encoded by a single transcript which encompasses 19 kb of the cor gene cluster. In case of polyketide biosynthesis, the at domain is crucial for controlling the recognition of the extender unit. Molecular basis for the biosynthesis of an unusual chain. The streptomyces glaucescens tcmkl polyketide synthase and tcmn polyketide cyclase genes govern the size and shape of aromatic polyketides b. Polyketide synthesis is related to fatty acid biosynthesis. Among these compounds, the polyketides form a large and structurally diverse group.
The shikimic acid pathway, ubiquitous in microorganisms and plants, provides precursors for the biosynthesis of primary metabolites such as the aromatic amino acids and folic acid. In the present study, the nucleotide sequence was determined for a 4kb region located at the 3. This book is the second of two volumes that deal with discovery of chemical pathways of biosynthesis of natural products secondary metabolites. Tetracyclines are aromatic polyketides biosynthesized by bacterial type ii polyketide synthases pkss. Beyond the enediyne core, several structural features of the enediyne antitumor antibiotics are polyketide derived.
Pdf recombinatorial biosynthesis of polyketides daslav. It was possible to predict the basic structure of a. Methods and protocols serves as a valuable reference for those experienced in studying nrps and pks enzymes, pathways, and natural products as well as a gateway for those just entering the field. Erythromycin, a broad spectrum antibiotic synthesized by the bacterium s. Romagni encyclopedia of life support systems eolss the primary pathways involved in the production of secondary metabolites are the acetylpolymalonyl polyketide, shikimate and mevalonate pathways. Modular polyketide synthases pkss are a large family of multifunctional enzymes responsible for the biosynthesis of numerous bacterial natural products such as erythromycin and rifamycin. Vectorial polyketide biosynthesis on an assembly line polyketide synthase is the most distinctive property of this family of biological machines, while providing the key conceptual tool for the bioinformatic decoding of new antibiotic pathways. There are three types of pkss type i, type ii, and type iii in streptomyces responsible for producing polyketides. The assembly line enzymology of polyketide biosynthesis. Coronafacic acid cfa is the polyketide component of the phytotoxin coronatine, a virulence factor of the plant pathogen pseudomonas syringae. It then continues with methods for the analysis of these pathways including conventional enzymological assays, contemporary mass spectrometric analysis techniques, specialized molecular biological approaches applicable to nrpss and pkss, and small molecule analysis. The availability of the crystal structure of complete module of pks 16, 90 or its constituent domains as acp, dehydratase, thioesterase 93, 94 has provided a better understanding on the mechanism of macrolactone biosynthesis. Engineered polyketide biosynthesis and biocatalysis in. To this end, we have sequenced the gene cluster of oxytetracycline oxy and otc genes pks genes from streptomyces rimosus.
Aug 14, 2005 type i polyketide synthase pks genes consist of modules. Cox, school of chemistry, university of bristol, bristol, united kingdom. Preliminary phylogenetic analysis indeed has led to the identification of lnmg homologs from these clusters fig. Naturally, they are found in bacteria, fungi, plants, protists, insects, mollusks, and sponges. Fungi produce a wide variety of biologically active compounds. After sequence analysis of the biosynthetic gene cluster, one gene, dpga, for a predicted polyketide synthase pks was identified, sharing 2030% identity with plant chalcone synthases. This paper focuses on the biosynthesis of polyketides in streptomyces with three structurallydifferent types of pkss. Figure 2 b a scoa o scoa oo o ks d scoa oo o scoa o c e ks ks at h enzs o h 3co o o dh senz o o h3c o o o o at at dh dh kr acp acp acp ho o h c oh oh oh o. Typically the products of microbial secondary biosynthesis, polyketides are synthesized by an evolutionarily related but architecturally diverse family of multifunctional enzymes called polyketide synthases. Modulation of polyketide synthase activity by accessory. The megalomicin gene cluster was used as the source for the construction of two artificial operons that contained the genes encoding the deoxysugar biosynthetic and tailoring enzymes. Chapter 1 introduction to polyketide biosynthesis request pdf. Fabh synthesizes 4methyl3oxohexanoylacp from 2methylbutyrylcoa and malonylacp. In this novel polyketide synthesis pathway figure 6, the initial condensation is catalyzed by fabh, a.
Nov 10, 2000 analogous to fatty acids and reduced polyketide biosynthesis, aromatic polyketide biosynthesis is accomplished by the polyketide synthases that catalyze sequential decarboxylative condensation between the starter and extender units to yield a linear poly. The marilones and marilines are a new family of polyketide metabolites recently isolated from the marinederived fungus stachylidium sp. A dual role for a polyketide synthase in dynemicin enediyne and anthraquinone biosynthesis. Biosynthesis of polyketide natural products youtube. The first volume covered the use of isotopes in biosynthetic research and the formation of enzyme cofactors and reduced polyketides. Polyketides from biosynthesis to total synthesis wiley. The polyketide chains produced by a minimal polyketide synthase are often further derivitized and modified into bioactive natural products. This book provides an excellent overview of the chemistry, genetics, physiology, and enzymology of these compounds. The stereochemistry of complex polyketide biosynthesis. The polyketide chains produced by a minimal polyketide synthase are often further derivatized and modified into bioactive natural products palmitic acid is an example of a polyketide since it is formed by the condensation of one acetylcoa primer and seven malonylcoa extender units. Dehydratase dh catalytic domains play an important role during polyketide biosynthesis through the dehydration of the nascent polyketide intermediate to provide olefins.
Polyketides are a fascinating class of natural products with highly diverse, often complex structures combined with a likewise impressive breath of strong and selective biological activities. A principal limitation for fundamental biochemical studies of these modular. Mcglincheya, yuan liua, christopher hazzardb, laura l. A principal limitation for fundamental biochemical studies of these modular megasynthases, as well as for their. This volume presents an overview of nonribosomal peptide synthetase nrps and polyketide synthase pks structure and function. The latter undergoes regiospecific reduction, aromatization, or. Biosynthesis of polyketides involves a group of enzyme activities called polyketide synthases pkss. The reaction takes place at the ks n bound end of the chain, so that the chain moves out one position and the elongation group becomes the new bound group. Oxytetracycline otc 3 is a well studied polyketide natural product and is an important example of type ii polyketide biosynthesis.
Summary polyketide natural products show great promise as medicinal agents. A hostvector system for analysis and manipulation of. Microorganisms free fulltext biosynthesis of polyketides. Recent literature on polyketide biosynthesis suggests that polyketide synthases have much greater diversity in both mechanism and structure than the current type i, ii and iii paradigms. Engineering actinomycetes for biosynthesis of macrolactone. Nonribosomal peptide and polyketide biosynthesis methods. High diversity of polyketide synthase genes and the melanin. Polyketides are a large group of secondary metabolites that have notable variety in their structure and function.
This group of synthases has a characteristic modular organization, and each module within a pks carries out one cycle of polyketide chain elongation. Coronafacic acid cfa is the polyketide component of coronatine cor, a phytotoxin produced by the plantpathogenic bacterium pseudomonas syringae. Kato y et al 2002 functional expression of genes involved in the biosynthesis of the novel polyketide chain extension unit, methoxymalonylacyl carrier protein, and engineered biosynthesis of 2desmethyl2methoxy6deoxyerythronolide b. An escherichia coli strain capable of producing the potent antibiotic erythromycin c ery c was developed by expressing 17 new heterologous genes in a 6deoxyerythronolide b 6deb producer strain. Modular polyketide synthases type i pkss in bacteria are responsible for synthesizing a significant percentage of bioactive natural products.
May 27, 2012 an overview of polyketides and their biosynthesis. The combinatorial biosynthesis of unnatural products. Biosynthesis of the salinosporamide a polyketide synthase substrate chloroethylmalonylcoenzyme a from sadenosyllmethioninealessandra s. Herein, we have identified the biosynthetic gene cluster of gregatin a 1 in penicillium sp.
In brief, a pks loads its substrates acyl and malonyl coa using an acyltransferase at domain onto an acyl. Authoritative and practical, nonribosomal peptide and polyketide biosynthesis. The streptomyces peucetius dpsc gene determines the choice of. The lovastatin biosynthesis cluster contains two type i polyketide synthase genes. The biosynthesis of 6deoxyerythronolide b 6deb has become the textbook example for modular polyketide synthases. The streptomyces glaucescens tcmkl polyketide synthase and.
The biosynthesis of polyketides shares a great deal of similarity to that of fatty acids, and much of our current understanding of pks enzymes has benefited from extensive studies on the fatty acid synthase fas systems 1,3. Engineered biosynthesis of a novel amidated polyketide. Analogous to fatty acids and reduced polyketide biosynthesis, aromatic polyketide biosynthesis is accomplished by the polyketide synthases that catalyze sequential decarboxylative condensation between the starter and extender units to yield a linear poly. Polyketide biosynthesis beyond the type i, ii and iii. Polyketide biosynthesis in bacteria and fungi is related to fatty acid metabolism but differs in that some of the reduction or dehydration reactions catalyzed by a polyketide synthase pks can be suppressed at specific biosynthetic steps. The biosyntheses of polyketides share striking similarities with fatty acid biosynthesis the pks genes for a certain polyketide are usually organized in one operon or in gene clusters. Advanced genetic analysis of these remarkable systems is often seriously hampered by the large size 40 kb of pks gene clusters, and, notwithstanding their considerable fundamental and biotechnological. Polyketides are synthesised from simple precursors by iterative chemistry catalysed by highly complex multifunctional enzyme systems, megasynthases known as polyketide synthases pks. Sep 25, 2019 polyketides are usually biosynthesized through the decarboxylative condensation of malonylcoa derived extender units in a similar process to fatty acid biosynthesis a claisen condensation. Polyketide synthesis an overview sciencedirect topics. Start of the phenylpropanoid pathway synthesized by the shikimate pathway, the amino acid phenylalanine is the primary starting molecule of this pathway in plants figure 1. Biosynthetic studies of novel polyketides from the marine.
A polyketide synthase in glycopeptide biosynthesis the biosynthesis of the nonproteinogenic amino acid s. Substrates besides acetylcoa and malonylcoa can be used by pkss to assemble the carbon chain. Consequently, the cloning and characterization of the cfa biosynthetic gene cluster. The acpbound elongation group reacts in a claisen condensation with the ksbound polyketide chain under co 2 evolution, leaving a free ks domain and an acpbound elongated polyketide chain. In the daunorubicin biosynthesis gene cluster of streptomyces peucetius, directly downstream of the genes encoding the. High diversity of polyketide synthase genes and the melanin biosynthesis gene cluster in penicillium marneffei patrick c. Iterative polyketide biosynthesis by modular polyketide. Polyketide synthase pks enzymes continue to hold great promise as synthetic biology platforms for the production of novel therapeutic agents, biofuels, and commodity chemicals. Sign up for the nature briefing newsletter what matters in science, free to your inbox daily. Polyketides are usually biosynthesized through the decarboxylative condensation of malonylcoa derived extender units in a similar process to fatty acid biosynthesis a claisen condensation. Polyketides exhibit a wide range of bioactivities such as antibacterial, antifungal, anticancer, antiviral, immunesuppressing, anticholesterol, and antiinflammatory activity.
Biosynthesis of the salinosporamide a polyketide synthase. Balhimycin, a vancomycintype antibiotic fromamycolatopsis mediterranei, contains the unusual amino acid s3,5dihydroxyphenylglycine dpg, with an acetatederived carbon backbone. Our current knowledge of polyketide biosynthesis largely is based on the analysis of polyketide synthases pkss in actinomycetes and other grampositive bacteria. A dual role for a polyketide synthase in dynemicin. By the 1980s, it was clearly evident from genetic analyses of the two. Structural organization of microcystin biosynthesis in. Application of isotopic methods to secondary metabolic pathways the biosynthesis of aliphatic polyketides cofactor biosynthesis. In saccaropolyspora erythrae, it is converted to the biologically active erythromycin by hydroxylation followed by addition of sugars. Type ii polyketides, also known as bacterial aromatic polyketides, are a group of compounds produced naturally in bacteria from a poly. A turnstile mechanism for the controlled growth of. This paper focuses on the biosynthesis of polyketides in streptomyces with three structurallydi erent types of pkss. Polyketide biosynthesis an overview sciencedirect topics.