The ks domain in an iterative pks can recapture the growing polyketide chain after each round of condensation and terminate polyketide biosynthesis at a precise stage. Herein, we present that the biosynthetic pathways of two immunosuppressants, dalmanol a and acetodalmanol a, result from an unspecific monooxygenase triggered hybrid 2019 chemical science hot article collection. Even once the threedimensional organization of a single polyketide synthase module is resolved, there is still no experimentally based structural prototype for a bimodular not to mention a multimodular polyketide synthase. The fatty acid synthase fas is a multidomain protein complex maier et al. Each module within the synthase complex incorporates a single carboxylic acid substrate, derived from a pool of simple precursors, into the pathway product fig. Polyketide synthase pathway discovery from soil metagenomic. Thus, the relative spatial dispositions of adjacent debs modules cannot yet be. The polyketide synthase gene an15g07920 was known in aspergillus niger cbs 5. Here we present the synthesis of unnatural unique polyketide alkaloid hybrid molecules by exploiting the enzyme reaction using precursordirected and structurebased approaches. Following each condensation reaction, the new betaketo group may be reduced, dehydrated, and reduced again. Polyketide synthases produce compounds of high structural and functional diversity. The biosynthetic pathway to ossamycin, a macrocyclic polyketide.
An analysis of these genes may provide new targets for genetic improvement to increase relevant secondary metabolites and enhance the plant tolerance to biotic and. Probing selectivity and creating structural diversity. Engineered biosynthesis of regioselectively modified. Unraveling the iterative type i polyketide synthases. Analogous to fatty acid synthases fass, polyketide synthases pkss catalyze the biosynthesis of polyketides through repetitive cc bond. Polyketide natural products constitute a broad class of compounds with diverse structural features and biological activities. High diversity of polyketide synthase genes and the. Polyketides are alarge family of pharmaceutically important natural products,and the structural modification of. Cheng yg, tang gl, shen b 2003 type i polyketide synthase requiring a discrete acyltransferase for polyketide biosynthesis. Structural and evolutionary relationships of atless. Structural basis of a broadly selective acyltransferase from.
Benzophenone synthase and chalcone synthase from hypercum androsaemum cell cultures. Lohman, tao liu, and ben shen, department of chemistry, the scripps research institute, jupiter, fl 33458, usa. A fosmid metagenomic library constructed from soil at the hancock agricultural research station in hancock, wi, 18,432 clones, average insert of 42 kb was spotted onto a nylon membrane. The carbon atom source of ta is known from the amino acid ornithine 4,5,6,7 and acetate units 8,9,10 for a long time by elaborate isotopelabeling experiments. Prokaryotic and eukaryotic pkss form a wide variety of biomolecules, including longchain fatty acids, pigments, immunosuppressants, and antibiotics monaghan and tkacz, 1990. High diversity of polyketide synthase genes and the melanin.
Williamsa polyketides are a large group of structurally diverse secondary metabolites with significant therapeutic utility. Polyketide natural products include many clinically important drugs such as erythromycin antibacterial, epothilone anticancer, rapamycin immunosuppressant, and lovastatin antihypercholesterolemic. We were able to produce various phoslactomycin derivatives with altered side. Novel insights into evolution of protistan polyketide synthases. Manual inspection and curation using the program artemis 18 led to the defi. Advances in polyketide synthase structure and function. 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. Identification of a putative polyketide synthase gene involved.
We have created phoslactomycin polyketide synthase. The sequencestructurefunction relationship of polyketide biosynthesis. This enzyme catalyzes the condensation of malonyl coa and enzymebound acyl group to afford complex fatty. Mutant malonylcoa synthetases with altered specificity for polyketide synthase extender unit generation irina koryakina and gavin j.
Polyketide synthases pkss are one of the most profound. Synthesis of three bioactive aromatic compounds by. Each type i polyketide synthase module consists of several domains with defined functions, separated by short spacer regions. It is commonly found in the actinomycete bacteria, saccharopolyspora erythraea. National centre for biological sciences, uas campus, bellary road, bangalore 560065, india. Thorsten lumbscha adepartment of botany, the field museum, 1400 south lake shore drive, chicago, il 60605, usa bleibnizinstitut fu. The onetoone correspondence between domains and biosynthetic transformations explains how programming is achieved in this modular pks. Engineering a polyketide with a longer chain by insertion of an extra module into the erythromycinproducing polyketide synthase.
Complete reconstitution and deorphanization of the 3 mda. Unlike all other pkss, these proteins do not have a phosphopantetheinyl ppant arm on which the growing polyketide chains are tethered. Tropane alkaloids biosynthesis involves an unusual type. Surprisingly, the modular polyketide synthase uses only. Hspks1 from huperzia serrata is a type iii polyketide synthase pks with remarkable substrate tolerance and catalytic potential.
Acp is the acyl carrier protein, at acyltransferase, ks ketosynthase, and kr0 a ketoreductase homologue that lacks nadphdependent. Pdf polyketidebased pharmaceuticals are some of our most. Pks polyketide synthase td terminal domain introduction polyketides are a large family of natural products found in bacteria, fungi and plants, and include many clinically important drugs such as tetracycline, daunorubicin, erythromycin, rapamycin and lovastatin. They are biosynthesized from acyl coa precursors by polyketide synthases pkss. Accordingly, we created a series of hybrid pks modules bearing exchanged te domains from heterologous pathways, and challenged them in vitro with both native and non. Modular polyketide synthase pks enzymatic complexes contain conserved ketoacyl synthase ks domains, and most pks biosynthetic pathways exceed 30 kb in size. Mutant malonylcoa synthetases with altered specificity for.
The mycolatecontaining compounds constitute major pathogenicity factors of mycobacterium tuberculosis. Structural and evolutionary relationships of atless type i polyketide synthase ketosynthases. Division of pharmaceutical sciences, university of wisconsinmadison, madison, wi 53705, usa. This is a pdf file of an unedited manuscript that has been. Engineering modular polyketide synthases for production of. Each module incorporates the essential ks, at and acp domains, while all but one include optional reductive activities kr, dh, er.
An iterative type i polyketide synthase initiates the. Polyketide synthase pks enzymes are large multidomain complexes that structurally and. Kavli institute for theoretical physics, kohn hall, ucsb, santa barbara, ca 93106, usa. The origins of specificity in polyketide synthase protein interactions mukund thattai1, yoram burak2, boris i. The order of modules and domains of a complete polyketide synthase is as follows in the order nterminus to cterminus.
Type i polyketide synthases pkss are multifunctional enzymes that are organized into modules, each of which minimally contains a. Structural and evolutionary relationships of atless type i. The streptomyces glaucescens tcmkl polyketide synthase. Mechanistic insights and unsolved problems chaitan khosla, daniel herschlag, david e. These structures revealed the molecular basis for the stereoselectivity and substrate. Probing selectivity and creating structural diversity through. At in the apo form and in complex with benzylmalonyl and pentynylmalonyl extender unit mimics. Pdf structure of a modular polyketide synthase researchgate. 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. Type iii polyketide synthases in natural product biosynthesis. The polyketide synthase pks catalyzes a novel mechanism. The polyketide synthase reactions are shown on top. The origins of specificity in polyketide synthase protein.
Fungal polyketide synthase pks 286 is a large protein and consists of a single set of module containing a keto synthase ks, an acyltransferase at, a thioesteraseclaisen cyclase tecyc, and two acyl carrier protein acp domains. Here, we report the discovery and structure elucidation of the nocap nocardiosisassociated polyketide aglycone by first fully reconstituting the nocap synthase in vitro from purified. They are produced as secondary metabolites primarily by bacteria and fungi hopwood 1997. Micacocidin is a bacterial natural product with pronounced activity against the human pathogen mycoplasma pneumoniae. Dalmanol biosyntheses require coupling of two separate. Phylogenomic analysis of type i polyketide synthase genes in pathogenic and saprobic ascomycetes scott kroken, n. Their biosynthetic machinery, represented by type i polyketide synthases pkss, has an architecture in which successive modules catalyse twocarbon linear. Type i polyketide synthases may have evolved through. Ossamycin cluster sequence file is available from the. The biosyntheses of polyketides share striking similarities with fatty acid biosynthesis. Jun 20, 20 micacocidin is a bacterial natural product with pronounced activity against the human pathogen mycoplasma pneumoniae.
Structure of a modular polyketide synthase article pdf available in nature 5107506. Polyketide synthases pkss are structurally and functionally related to fatty acid synthases fass, as both enzyme classes catalyzes the condensation of activated primary metabolites acetylcoa and malonylcoa to form bketoacetyl polymers linked to the enzyme by thioester bonds. Here we present the synthesis of unnatural unique polyketidealkaloid hybrid molecules by exploiting the enzyme reaction using precursordirected and structurebased approaches. Polyketide biosynthesis beyond the type i, ii and iii. Bioglass crystallization of type iii polyketide synthase. Polyketide synthase secrets revealed june 23, 2014 issue. Department of plant and microbial biology, university of california. Shraiman2 1 national centre for biological sciences, bangalore, india, 2 kavli institute for theoretical physics, university of california santa barbara, santa barbara, california, united. Polyketides are a large class of structurally and pharmacologically diverse molecules, including many antibiotics and antitumor drugs ohagan 1991. They are biosynthesized from short carboxylic acid precursors by polyketide synthases pkss. Users can submit their protein sequences in fasta format to predict whether the given protein sequence belongs to type iii polyketide synthase or not. Polyketide synthase an overview sciencedirect topics.
Research article open access unexpected link between polyketide synthase and calcium carbonate biomineralization motoki hojo1,6, ai omi1,7, gen hamanaka2, kazutoshi shindo3, atsuko shimada1, mariko kondo4, takanori narita1,8, masato kiyomoto2, yohei katsuyama5, yasuo ohnishi5, naoki irie1 and hiroyuki takeda1 abstract. Chalcone synthase like proteins are comparatively small proteins with a single polypeptide chain and are involved in the biosynthesis of precursors for flavonoids. Here, we report the discovery and structure elucidation of the nocap nocardiosisassociated polyketide aglycone by first fully reconstituting the nocap synthase in vitro from purified protein components followed by heterologous expression in e. Evolutionary and functional analysis of mulberry type iii. Growing evidence indicates that the thioesterase te domain is a significant bottleneck within engineered modular pks systems.
Structural biochemistrypolyketide synthases wikibooks. Koch a dissertation submitted in partial fulfillment of the requirements for the degree of doctor of philosophy cancer biology in the university of michigan 2017 doctoral committee. Polyketide synthases and coenzyme coa ligases were tested to determine the optimal combination of genes for the synthesis of each compound. Pksiiipred is the type iii polyketide synthase prediction server based on svm. Polyketide synthase type iii isolated from uncultured deep. Request pdf advances in polyketide synthase structure and function recent progress in the understanding of polyketide synthase pks continues to fuel the growth of combinatorial biosynthesis. Download typeiii polyketide synthase prediction for free. Polyketidepolyketide hybrids are unique natural products with promising bioactivity, but the hybridization processes remain poorly understood. Several nocardia strains associated with nocardiosis, a potentially lifethreatening disease, house a nonamodular assembly line polyketide synthase pks that presumably synthesizes an unknown polyketide. Assembly line polyketide synthases acs publications american. The study is a milestone in the pks field, says polyketide biosynthesis specialist shiouchuan sheryl tsai of the university of california, irvine. We also tested several constructs and identified the best one for increasing levels of endogenous substrates for chorismate, anthranilate, and malonylcoa. Despite their diverse end products, pkss are composed of very similar.
Polyketide synthase pks the pks family share a number of characteristics with the family of fatty acid synthases fas. Type iii polyketide synthases are important for the biosynthesis of flavonoids and various plant polyphenols. However, very few it1pkss have been discovered in bacteria. The streptomyces glaucescens tcmkl polyketide synthase and. Structural basis of a broadly selective acyltransferase. Pksnonribosomal peptide synthethases 59,60 nrps produce similar polyene such as 73 with acyltetramate moiety at the terminal of the polyketide backbone. Numerous iterative type i polyketide synthases it1pkss have been discovered in fungi that can synthesize structurally diverse bioactive molecules. In a noniterative modular pks, each module is used only once, and the polyketide intermediate is transferred to a downstream module for chain elongation. Inclusion of c 2acetate in the growth medium resulted in the c enrichment of c8c9, c12c, c14c15, c18c19, c20c21, c26c27, and c32c33, consistent with the incorporation of seven malonylcoa extender units into the rapamycin polyketide core fig. Rifdh10, the dehydratase domain from the terminal module of the rifamycin polyketide synthase, catalyzes the stereospecific syn dehydration of the model substrate 2s,3s2methyl3hydroxypentanoylrifacp10, resulting in the exclusive formation of e2methyl2pentenoylrifacp10.
Engineering polyketide synthase pks pathways that efficiently produce new metabolites requires an understanding of substrate selectivity, flexibility, and sites of failure during chain elongation, processing and termination. Sa response pathways using a fungal polyketide synthase pks gene. Their biosynthetic machinery, represented by type i polyketide synthases pkss, has an architecture in which successive modules catalyse twocarbon linear extensions. Production of 6methylsalicylic acid by expression of a. Cs bond cleavage by a polyketide synthase domain ming ma, jeremy r. Understanding substrate selectivity of phoslactomycin.
A polyketide synthase encoded by the gene an15g07920 is. Mar 14, 2018 structural basis of a broadly selective acyltransferase from the polyketide synthase of splenocin yuan li key laboratory of combinatorial biosynthesis and drug discovery wuhan university, ministry of education, wuhan university school of pharmaceutical sciences, 185 donghu road. Debs 6deoxyerythronolide b synthase is a type 1 polyketide synthase responsible for the production of the macrolide 6deoxyerythronolide b 6deb, a aglycone precursor of the antibiotic erythromycin. Phylogenomic analysis of type i polyketide synthase genes. High diversity of polyketide synthase genes and the melanin biosynthesis gene cluster in penicillium marneffei patrick c. Investigations into the structure and function of type i.
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. Mulberry plants have abundant polyphenols, but very little is known about the mulberry type iii polyketide synthase genes. Tropane alkaloids biosynthesis involves an unusual type iii. Genome resequencing analysis revealed that the gene an15g07920 is also present in the ochratoxinproducing a. Unexpected link between polyketide synthase and calcium.
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