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Ali O, Szabó A. Review of Eukaryote Cellular Membrane Lipid Composition, with Special Attention to the Fatty Acids. Int J Mol Sci 2023; 24:15693. [PMID: 37958678 PMCID: PMC10649022 DOI: 10.3390/ijms242115693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/24/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
Biological membranes, primarily composed of lipids, envelop each living cell. The intricate composition and organization of membrane lipids, including the variety of fatty acids they encompass, serve a dynamic role in sustaining cellular structural integrity and functionality. Typically, modifications in lipid composition coincide with consequential alterations in universally significant signaling pathways. Exploring the various fatty acids, which serve as the foundational building blocks of membrane lipids, provides crucial insights into the underlying mechanisms governing a myriad of cellular processes, such as membrane fluidity, protein trafficking, signal transduction, intercellular communication, and the etiology of certain metabolic disorders. Furthermore, comprehending how alterations in the lipid composition, especially concerning the fatty acid profile, either contribute to or prevent the onset of pathological conditions stands as a compelling area of research. Hence, this review aims to meticulously introduce the intricacies of membrane lipids and their constituent fatty acids in a healthy organism, thereby illuminating their remarkable diversity and profound influence on cellular function. Furthermore, this review aspires to highlight some potential therapeutic targets for various pathological conditions that may be ameliorated through dietary fatty acid supplements. The initial section of this review expounds on the eukaryotic biomembranes and their complex lipids. Subsequent sections provide insights into the synthesis, membrane incorporation, and distribution of fatty acids across various fractions of membrane lipids. The last section highlights the functional significance of membrane-associated fatty acids and their innate capacity to shape the various cellular physiological responses.
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Affiliation(s)
- Omeralfaroug Ali
- Agrobiotechnology and Precision Breeding for Food Security National Laboratory, Institute of Physiology and Animal Nutrition, Department of Animal Physiology and Health, Hungarian University of Agriculture and Life Sciences, Guba Sándor Str. 40, 7400 Kaposvár, Hungary;
| | - András Szabó
- Agrobiotechnology and Precision Breeding for Food Security National Laboratory, Institute of Physiology and Animal Nutrition, Department of Animal Physiology and Health, Hungarian University of Agriculture and Life Sciences, Guba Sándor Str. 40, 7400 Kaposvár, Hungary;
- HUN-REN-MATE Mycotoxins in the Food Chain Research Group, Hungarian University of Agriculture and Life Sciences, Guba Sándor Str. 40, 7400 Kaposvár, Hungary
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2
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Williams E, Bachvaroff T, Place A. A Comparison of Dinoflagellate Thiolation Domain Binding Proteins Using In Vitro and Molecular Methods. Mar Drugs 2022; 20:581. [PMID: 36135770 PMCID: PMC9500876 DOI: 10.3390/md20090581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/03/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
Dinoflagellates play important roles in ecosystems as primary producers and consumers making natural products that can benefit or harm environmental and human health but are also potential therapeutics with unique chemistries. Annotations of dinoflagellate genes have been hampered by large genomes with many gene copies that reduce the reliability of transcriptomics, quantitative PCR, and targeted knockouts. This study aimed to functionally characterize dinoflagellate proteins by testing their interactions through in vitro assays. Specifically, nine Amphidinium carterae thiolation domains that scaffold natural product synthesis were substituted into an indigoidine synthesizing gene from the bacterium Streptomyces lavendulae and exposed to three A. carterae phosphopantetheinyl transferases that activate synthesis. Unsurprisingly, several of the dinoflagellate versions inhibited the ability to synthesize indigoidine despite being successfully phosphopantetheinated. However, all the transferases were able to phosphopantetheinate all the thiolation domains nearly equally, defying the canon that transferases participate in segregated processes via binding specificity. Moreover, two of the transferases were expressed during growth in alternating patterns while the final transferase was only observed as a breakdown product common to all three. The broad substrate recognition and compensatory expression shown here help explain why phosphopantetheinyl transferases are lost throughout dinoflagellate evolution without a loss in a biochemical process.
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Affiliation(s)
| | | | - Allen Place
- Institute for Marine and Environmental Technologies, University of Maryland Center for Environmental Science, 701 East Pratt St., Baltimore, MD 21202, USA
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3
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Dinoflagellate Phosphopantetheinyl Transferase (PPTase) and Thiolation Domain Interactions Characterized Using a Modified Indigoidine Synthesizing Reporter. Microorganisms 2022; 10:microorganisms10040687. [PMID: 35456738 PMCID: PMC9027781 DOI: 10.3390/microorganisms10040687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 02/01/2023] Open
Abstract
Photosynthetic dinoflagellates synthesize many toxic but also potential therapeutic compounds therapeutics via polyketide/non-ribosomal peptide synthesis, a common means of producing natural products in bacteria and fungi. Although canonical genes are identifiable in dinoflagellate transcriptomes, the biosynthetic pathways are obfuscated by high copy numbers and fractured synteny. This study focuses on the carrier domains that scaffold natural product synthesis (thiolation domains) and the phosphopantetheinyl transferases (PPTases) that thiolate these carriers. We replaced the thiolation domain of the indigoidine producing BpsA gene from Streptomyces lavendulae with those of three multidomain dinoflagellate transcripts and coexpressed these constructs with each of three dinoflagellate PPTases looking for specific pairings that would identify distinct pathways. Surprisingly, all three PPTases were able to activate all the thiolation domains from one transcript, although with differing levels of indigoidine produced, demonstrating an unusual lack of specificity. Unfortunately, constructs with the remaining thiolation domains produced almost no indigoidine and the thiolation domain for lipid synthesis could not be expressed in E. coli. These results combined with inconsistent protein expression for different PPTase/thiolation domain pairings present technical hurdles for future work. Despite these challenges, expression of catalytically active dinoflagellate proteins in E. coli is a novel and useful tool going forward.
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Williams EP, Bachvaroff TR, Place AR. A Global Approach to Estimating the Abundance and Duplication of Polyketide Synthase Domains in Dinoflagellates. Evol Bioinform Online 2021; 17:11769343211031871. [PMID: 34345159 PMCID: PMC8283056 DOI: 10.1177/11769343211031871] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Accepted: 06/23/2021] [Indexed: 11/17/2022] Open
Abstract
Many dinoflagellate species make toxins in a myriad of different molecular configurations but the underlying chemistry in all cases is presumably via modular synthases, primarily polyketide synthases. In many organisms modular synthases occur as discrete synthetic genes or domains within a gene that act in coordination thus forming a module that produces a particular fragment of a natural product. The modules usually occur in tandem as gene clusters with a syntenic arrangement that is often predictive of the resultant structure. Dinoflagellate genomes however are notoriously complex with individual genes present in many tandem repeats and very few synthetic modules occurring as gene clusters, unlike what has been seen in bacteria and fungi. However, modular synthesis in all organisms requires a free thiol group that acts as a carrier for sequential synthesis called a thiolation domain. We scanned 47 dinoflagellate transcriptomes for 23 modular synthase domain models and compared their abundance among 10 orders of dinoflagellates as well as their co-occurrence with thiolation domains. The total count of domain types was quite large with over thirty-thousand identified, 29 000 of which were in the core dinoflagellates. Although there were no specific trends in domain abundance associated with types of toxins, there were readily observable lineage specific differences. The Gymnodiniales, makers of long polyketide toxins such as brevetoxin and karlotoxin had a high relative abundance of thiolation domains as well as multiple thiolation domains within a single transcript. Orders such as the Gonyaulacales, makers of small polyketides such as spirolides, had fewer thiolation domains but a relative increase in the number of acyl transferases. Unique to the core dinoflagellates, however, were thiolation domains occurring alongside tetratricopeptide repeats that facilitate protein-protein interactions, especially hexa and hepta-repeats, that may explain the scaffolding required for synthetic complexes capable of making large toxins. Clustering analysis for each type of domain was also used to discern possible origins of duplication for the multitude of single domain transcripts. Single domain transcripts frequently clustered with synonymous domains from multi-domain transcripts such as the BurA and ZmaK like genes as well as the multi-ketosynthase genes, sometimes with a large degree of apparent gene duplication, while fatty acid synthesis genes formed distinct clusters. Surprisingly the acyl-transferases and ketoreductases involved in fatty acid synthesis (FabD and FabG, respectively) were found in very large clusters indicating an unprecedented degree of gene duplication for these genes. These results demonstrate a complex evolutionary history of core dinoflagellate modular synthases with domain specific duplications throughout the lineage as well as clues to how large protein complexes can be assembled to synthesize the largest natural products known.
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Affiliation(s)
- Ernest P Williams
- Institute of Marine and Environmental Technologies, University of Maryland Center for Environmental Science, Baltimore, MD, USA
| | - Tsvetan R Bachvaroff
- Institute of Marine and Environmental Technologies, University of Maryland Center for Environmental Science, Baltimore, MD, USA
| | - Allen R Place
- Institute of Marine and Environmental Technologies, University of Maryland Center for Environmental Science, Baltimore, MD, USA
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5
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Zhu X, Li S, Liu L, Li S, Luo Y, Lv C, Wang B, Cheng CHK, Chen H, Yang X. Genome Sequencing and Analysis of Thraustochytriidae sp. SZU445 Provides Novel Insights into the Polyunsaturated Fatty Acid Biosynthesis Pathway. Mar Drugs 2020; 18:md18020118. [PMID: 32085426 PMCID: PMC7073664 DOI: 10.3390/md18020118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/06/2020] [Accepted: 02/14/2020] [Indexed: 12/18/2022] Open
Abstract
Thraustochytriidae sp. have broadly gained attention as a prospective resource for the production of omega-3 fatty acids production in significant quantities. In this study, the whole genome of Thraustochytriidae sp. SZU445, which produces high levels of docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA), was sequenced and subjected to protein annotation. The obtained clean reads (63.55 Mb in total) were assembled into 54 contigs and 25 scaffolds, with maximum and minimum lengths of 400 and 0.0054 Mb, respectively. A total of 3513 genes (24.84%) were identified, which could be classified into six pathways and 44 pathway groups, of which 68 genes (1.93%) were involved in lipid metabolism. In the Gene Ontology database, 22,436 genes were annotated as cellular component (8579 genes, 38.24%), molecular function (5236 genes, 23.34%), and biological process (8621 genes, 38.42%). Four enzymes corresponding to the classic fatty acid synthase (FAS) pathway and three enzymes corresponding to the classic polyketide synthase (PKS) pathway were identified in Thraustochytriidae sp. SZU445. Although PKS pathway-associated dehydratase and isomerase enzymes were not detected in Thraustochytriidae sp. SZU445, a putative DHA- and DPA-specific fatty acid pathway was identified.
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Affiliation(s)
- Xingyu Zhu
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Shuangfei Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Longhua Innovation Institute for Biotechnology, Shenzhen University, Shenzhen 518060, China
| | - Liangxu Liu
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Siting Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Yanqing Luo
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Chuhan Lv
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Boyu Wang
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Longhua Innovation Institute for Biotechnology, Shenzhen University, Shenzhen 518060, China
| | - Christopher H. K. Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong 999077, China;
| | - Huapu Chen
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China;
| | - Xuewei Yang
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Longhua Innovation Institute for Biotechnology, Shenzhen University, Shenzhen 518060, China
- Correspondence:
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6
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Nielsen MR, Sondergaard TE, Giese H, Sørensen JL. Advances in linking polyketides and non-ribosomal peptides to their biosynthetic gene clusters in Fusarium. Curr Genet 2019; 65:1263-1280. [DOI: 10.1007/s00294-019-00998-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 05/20/2019] [Accepted: 05/22/2019] [Indexed: 11/24/2022]
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7
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Wielgusz K, Irzykowska L. Occurrence of pathogenic and endophytic fungi and their influence on quality of medicinal plants applied in management of neurological diseases and mental disorders. HERBA POLONICA 2018. [DOI: 10.1515/hepo-2017-0025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Summary
Due to increasing demand of medicinal plants (MPs), quality and safety more attention to the plant health should be paid. Among herb pathogens, especially fungi cause serious diseases in these plants decreasing yield and quality of herbal raw material. Some species, i.e. Fusarium sp., Alternaria sp., Penicillium sp. are known as mycotoxin producers. Paradoxically, self-treatment with herbal raw material can expose the patient to mycotoxin activity. In tissues of some MPs species, asymptomatically endophytic fungi residue. It is known that they are able to influence a biosynthesis of secondary metabolites in their host plant or produce biologically active compounds. Until recently these microorganisms have been neglected as a component of MPs, the reason why there have unexplored bioactivity and biodiversity. The paper presents an overview of herbal plants that are used in the treatment of nervous system diseases. Pathogenic fungi that infect these plants are described. It focused mainly on species producing harmful mycotoxins. The publication presents a list of these mycotoxins and a brief description of their effects on human health. The second part of this article provides information on the occurrence of endophytic fungi in herbal plants and their effects on human health. Coexistence of fungi and medicinal plants is not fully understood but can be crucial to ensure health and safety of patients with neurological diseases and mental disorders.
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Affiliation(s)
- Katarzyna Wielgusz
- Institute of Natural Fibers and Medicinal Plants Department of Breeding and Agriculture of Fibrous and Energetic Plants Wojska Polskiego 71b 60-630 Poznań , Poland
| | - Lidia Irzykowska
- Poznan University of Life Sciences Department of Phytopathology, Seed Science and Technology Dąbrowskiego 159 60-594 Poznań , Poland
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Zimorski V, Rauch C, van Hellemond JJ, Tielens AGM, Martin WF. The Mitochondrion of Euglena gracilis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 979:19-37. [PMID: 28429315 DOI: 10.1007/978-3-319-54910-1_2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In the presence of oxygen, Euglena gracilis mitochondria function much like mammalian mitochondria. Under anaerobiosis, E. gracilis mitochondria perform a malonyl-CoA independent synthesis of fatty acids leading to accumulation of wax esters, which serve as the sink for electrons stemming from glycolytic ATP synthesis and pyruvate oxidation. Some components (enzymes and cofactors) of Euglena's anaerobic energy metabolism are found among the anaerobic mitochondria of invertebrates, others are found among hydrogenosomes, the H2-producing anaerobic mitochondria of protists.
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Affiliation(s)
- Verena Zimorski
- Institute of Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Cessa Rauch
- Institute of Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Jaap J van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Aloysius G M Tielens
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, The Netherlands.,Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - William F Martin
- Institute of Molecular Evolution, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany.
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9
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Bertin MJ, Vulpanovici A, Monroe EA, Korobeynikov A, Sherman DH, Gerwick L, Gerwick WH. The Phormidolide Biosynthetic Gene Cluster: A trans-AT PKS Pathway Encoding a Toxic Macrocyclic Polyketide. Chembiochem 2016; 17:164-73. [PMID: 26769357 PMCID: PMC4878910 DOI: 10.1002/cbic.201500467] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Indexed: 11/09/2022]
Abstract
Phormidolide is a polyketide produced by a cultured filamentous marine cyanobacterium and incorporates a 16-membered macrolactone. Its complex structure is recognizably derived from a polyketide synthase pathway, but possesses unique and intriguing structural features that prompted interest in investigating its biosynthetic origin. Stable isotope incorporation experiments confirmed the polyketide nature of this compound. We further characterized the phormidolide gene cluster (phm) through genome sequencing followed by bioinformatic analysis. Two discrete trans-type acyltransferase (trans-AT) ORFs along with KS-AT adaptor regions (ATd) within the polyketide synthase (PKS) megasynthases, suggest that the phormidolide gene cluster is a trans-AT PKS. Insights gained from analysis of the mode of acetate incorporation and ensuing keto reduction prompted our reevaluation of the stereochemistry of phormidolide hydroxy groups located along the linear polyketide chain.
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Affiliation(s)
- Matthew J Bertin
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, MC 0212, La Jolla, CA, 92093, USA
| | - Alexandra Vulpanovici
- Department of Biochemistry and Biophysics, Oregon State University, 2011 Agricultural and Life Sciences, 2750 SW Campus Way, Corvallis, OR, 97331, USA
| | - Emily A Monroe
- Department of Biology, William Paterson University, 300 Pompton Road, Wayne, NJ, 07470, USA
| | - Anton Korobeynikov
- The Center for Algorithmic Biotechnology, Department of Statistical Modeling, St. Petersburg State University, Universitetskiy 28, Stary Peterhof, St. Petersburg, 198504, Russia
| | - David H Sherman
- Life Sciences Institute, Department of Medicinal Chemistry, Department of Chemistry, Department of Microbiology and Immunology, University of Michigan, 4008 Life Sciences Institute, 210 Washtenaw Avenue, Ann Arbor, MI, 48109, USA
| | - Lena Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, MC 0212, La Jolla, CA, 92093, USA
| | - William H Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, MC 0212, La Jolla, CA, 92093, USA) address.
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Sørensen JL, Sondergaard TE, Covarelli L, Fuertes PR, Hansen FT, Frandsen RJN, Saei W, Lukassen MB, Wimmer R, Nielsen KF, Gardiner DM, Giese H. Identification of the biosynthetic gene clusters for the lipopeptides fusaristatin A and W493 B in Fusarium graminearum and F. pseudograminearum. JOURNAL OF NATURAL PRODUCTS 2014; 77:2619-2625. [PMID: 25412204 DOI: 10.1021/np500436r] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The closely related species Fusarium graminearum and Fusarium pseudograminearum differ in that each contains a gene cluster with a polyketide synthase (PKS) and a nonribosomal peptide synthetase (NRPS) that is not present in the other species. To identify their products, we deleted PKS6 and NRPS7 in F. graminearum and NRPS32 in F. pseudograminearum. By comparing the secondary metabolite profiles of the strains we identified the resulting product in F. graminearum as fusaristatin A, and as W493 A and B in F. pseudograminearum. These lipopeptides have previously been isolated from unidentified Fusarium species. On the basis of genes in the putative gene clusters we propose a model for biosynthesis where the polyketide product is shuttled to the NPRS via a CoA ligase and a thioesterase in F. pseudograminearum. In F. graminearum the polyketide is proposed to be directly assimilated by the NRPS.
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Affiliation(s)
- Jens Laurids Sørensen
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University , DK-9000 Aalborg, Denmark
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11
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Van Wagoner RM, Satake M, Wright JLC. Polyketide biosynthesis in dinoflagellates: what makes it different? Nat Prod Rep 2014; 31:1101-37. [DOI: 10.1039/c4np00016a] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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12
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Jiao J, Zhang Y. Transgenic Biosynthesis of Polyunsaturated Fatty Acids: A Sustainable Biochemical Engineering Approach for Making Essential Fatty Acids in Plants and Animals. Chem Rev 2013; 113:3799-814. [DOI: 10.1021/cr300007p] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Jingjing Jiao
- Chronic Disease Research Institute,
Department of Nutrition and Food Hygiene, School of Public Health,
Zhejiang University, Hangzhou 310058, China
| | - Yu Zhang
- Department of Food Science and
Nutrition, School of Biosystems Engineering and Food Science, Zhejiang
University, Hangzhou 310058, China
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14
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Abstract
The iterative type I polyketide synthases (IPKSs) are central to the biosynthesis of an enormously diverse array of natural products in fungi. These natural products, known as polyketides, exhibit a wide range of biological activities and include clinically important drugs as well as undesirable toxins. The PKSs synthesize these structurally diverse polyketides via a series of decarboxylative condensations of malonyl-CoA extender units and β-keto modifications in a highly programmed manner. Significant progress has been made over the past few years in understanding the biosynthetic mechanism and programming of fungal PKSs. The continuously expanding fungal genome sequence data have sparked genome-directed discoveries of new fungal PKSs and associated products. The increasing number of fungal PKSs that have been linked to their products along with in-depth biochemical and structural characterizations of these large enzymes have remarkably improved our knowledge on the molecular basis for polyketide structural diversity in fungi. This Perspective highlights the recent advances and examines how the newly expanded paradigm has contributed to our ability to link fungal PKS genes to chemical structures and vice versa. The knowledge will help us navigate through the logarithmically expanding seas of genomic information for polyketide compound discovery and provided opportunities to reprogram these megasynthases to generate new chemical entities.
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Affiliation(s)
- Yit-Heng Chooi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095
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15
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Hansen FT, Sørensen JL, Giese H, Sondergaard TE, Frandsen RJ. Quick guide to polyketide synthase and nonribosomal synthetase genes in Fusarium. Int J Food Microbiol 2012; 155:128-36. [DOI: 10.1016/j.ijfoodmicro.2012.01.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 01/16/2012] [Accepted: 01/23/2012] [Indexed: 11/25/2022]
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Abstract
Biomimetic synthesis describes the field of organic chemistry that aims to emulate the natural, biosynthetic processes toward natural products. As well as providing insight into how molecules are formed in nature, the benefits of this approach to total synthesis are numerous and extend beyond the gains typical of traditional synthesis. For example, using biosynthetic proposals to design a synthetic route can highlight alternative methods to the desired target. The pursuit of biomimetic syntheses also promotes the development of new reactions to prove or disprove a biosynthetic proposal or to unravel mechanistic implications of a proposed biosynthesis and can lead to the identification of new natural products. Here we look at some recent compelling examples and examine how biomimetic synthesis has led to the discovery of new procedures and principles that would not have been found by other approaches.
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Affiliation(s)
- Mina Razzak
- Department of Biochemistry, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA
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Rogalski M, Carrer H. Engineering plastid fatty acid biosynthesis to improve food quality and biofuel production in higher plants. PLANT BIOTECHNOLOGY JOURNAL 2011; 9:554-64. [PMID: 21535359 DOI: 10.1111/j.1467-7652.2011.00621.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The ability to manipulate plant fatty acid biosynthesis by using new biotechnological approaches has allowed the production of transgenic plants with unusual fatty acid profile and increased oil content. This review focuses on the production of very long chain polyunsaturated fatty acids (VLCPUFAs) and the increase in oil content in plants using molecular biology tools. Evidences suggest that regular consumption of food rich in VLCPUFAs has multiple positive health benefits. Alternative sources of these nutritional fatty acids are found in cold-water fishes. However, fish stocks are in severe decline because of decades of overfishing, and also fish oils can be contaminated by the accumulation of toxic compounds. Recently, there is also an increase in oilseed use for the production of biofuels. This tendency is partly associated with the rapidly rising costs of petroleum, increased concern about the environmental impact of fossil oil and the attractive need to develop renewable sources of fuel. In contrast to this scenario, oil derived from crop plants is normally contaminant free and less environmentally aggressive. Genetic engineering of the plastid genome (plastome) offers a number of attractive advantages, including high-level foreign protein expression, marker-gene excision and transgene containment because of maternal inheritance of plastid genome in most crops. Here, we describe the possibility to improve fatty acid biosynthesis in plastids, production of new fatty acids and increase their content in plants by genetic engineering of plastid fatty acid biosynthesis via plastid transformation.
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Affiliation(s)
- Marcelo Rogalski
- Departamento de Ciências Biológicas, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, Piracicaba-SP. 13418-900, Brazil
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Bhetariya PJ, Madan T, Basir SF, Varma A, Usha SP. Allergens/Antigens, toxins and polyketides of important Aspergillus species. Indian J Clin Biochem 2011; 26:104-19. [PMID: 22468035 PMCID: PMC3107401 DOI: 10.1007/s12291-011-0131-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 04/15/2011] [Indexed: 12/11/2022]
Abstract
The medical, agricultural and biotechnological importance of the primitive eukaryotic microorganisms, the Fungi was recognized way back in 1920. Among various groups of fungi, the Aspergillus species are studied in great detail using advances in genomics and proteomics to unravel biological and molecular mechanisms in these fungi. Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Aspergillus nidulans and Aspergillus terreus are some of the important species relevant to human, agricultural and biotechnological applications. The potential of Aspergillus species to produce highly diversified complex biomolecules such as multifunctional proteins (allergens, antigens, enzymes) and polyketides is fascinating and demands greater insight into the understanding of these fungal species for application to human health. Recently a regulator gene for secondary metabolites, LaeA has been identified. Gene mining based on LaeA has facilitated new metabolites with antimicrobial activity such as emericellamides and antitumor activity such as terrequinone A from A. nidulans. Immunoproteomic approach was reported for identification of few novel allergens for A. fumigatus. In this context, the review is focused on recent developments in allergens, antigens, structural and functional diversity of the polyketide synthases that produce polyketides of pharmaceutical and biological importance. Possible antifungal drug targets for development of effective antifungal drugs and new strategies for development of molecular diagnostics are considered.
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Affiliation(s)
- Preetida J. Bhetariya
- Division of Plant Pathology, Indian Agricultural Research Institute, Pusa, New Delhi, 110012 India
| | - Taruna Madan
- National Institute for Research in Reproductive Health (NIRRH), Parel, Mumbai, 400012 India
| | - Seemi Farhat Basir
- Department of Biosciences, Jamia Millia Islamia, New Delhi, 110025 India
| | - Anupam Varma
- Division of Plant Pathology, Indian Agricultural Research Institute, Pusa, New Delhi, 110012 India
| | - Sarma P. Usha
- Division of Plant Pathology, Indian Agricultural Research Institute, Pusa, New Delhi, 110012 India
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Jiao YL, Wang LH, Jiao BH, Wang SJ, Fang YW, Liu S. Function analysis of a new type I PKS-SAT domain by Sat-Eat domain replacement. APPL BIOCHEM MICRO+ 2010. [DOI: 10.1134/s0003683810020043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Molnár I, Gibson DM, Krasnoff SB. Secondary metabolites from entomopathogenic Hypocrealean fungi. Nat Prod Rep 2010; 27:1241-75. [DOI: 10.1039/c001459c] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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21
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Combinatorial and Synthetic Biosynthesis in Actinomycetes. FORTSCHRITTE DER CHEMIE ORGANISCHER NATURSTOFFE / PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS, VOL. 93 2010; 93:211-37. [DOI: 10.1007/978-3-7091-0140-7_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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22
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Meier JL, Burkart MD. The chemical biology of modular biosynthetic enzymes. Chem Soc Rev 2009; 38:2012-45. [DOI: 10.1039/b805115c] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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23
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A quantum mechanics study on the reaction mechanism of chalcone formation from p-coumaroyl-CoA and malonyl-CoA catalyzed by chalcone synthase. Theor Chem Acc 2008. [DOI: 10.1007/s00214-008-0495-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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24
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Pankewitz F, Hilker M. Polyketides in insects: ecological role of these widespread chemicals and evolutionary aspects of their biogenesis. Biol Rev Camb Philos Soc 2008; 83:209-26. [PMID: 18410406 DOI: 10.1111/j.1469-185x.2008.00040.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Polyketides are known to be used by insects for pheromone communication and defence against enemies. Although in microorganisms (fungi, bacteria) and plants polyketide biogenesis is known to be catalysed by polyketide synthases (PKS), no insect PKS involved in biosynthesis of pheromones or defensive compounds have yet been found. Polyketides detected in insects may also be biosynthesized by endosymbionts. From a chemical perspective, polyketide biogenesis involves the formation of a polyketide chain using carboxylic acids as precursors. Fatty acid biosynthesis also requires carboxylic acids as precursors, but utilizes fatty acid synthases (FAS) to catalyse this process. In the present review, studies of the biosynthesis of insect polyketides applying labelled carboxylic acids as precursors are outlined to exemplify chemical approaches used to elucidate insect polyketide formation. However, since compounds biosynthesised by FAS may use the same precursors, it still remains unclear whether the structures that are formed from e.g. acetate chains (acetogenins) or propanoate chains (propanogenins) are PKS or FAS products. A critical comparison of PKS and FAS architectures and activities supports the hypothesis of a common evolutionary origin of these enzyme complexes and highlights why PKS can catalyse the biosynthesis of much more complex products than can FAS. Finally, we summarise knowledge which might assist researchers in designing approaches for the detection of insect PKS genes.
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Affiliation(s)
- Florian Pankewitz
- Freie Universität Berlin, Institute of Biology, Haderslebener Str. 9, D-12163 Berlin, Germany
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Abstract
There is a growing body of evidence suggesting that regular consumption of foods rich in omega-3 long chain polyunsaturated fatty acids has multiple positive health benefits. The fats and oils from marine fish contain high contents of these beneficial fatty acids but increased consumer demand has also increased strain on the ability of the world's fisheries to meet demand from wild capture. Many consumers are choosing fish oil supplements or are eating foods that have been complemented with fish oils instead of consuming fish directly. However, removing undesirable odors, flavors and contaminants is expensive. In contrast, oils derived from land plants such as soybean are inexpensive and contaminant free. Recent strides in plant molecular biology now allow the engineering of oilseeds for the production of novel fats and oils, including those synthesized by complex, multigene biosynthetic pathways such as the omega-3 long chain polyunsaturated fatty acids. Given the potential benefits to the environment with regards to overfishing and the health prospects of increased consumption of these healthy fatty acids, producing these fatty acids in oilseeds is a desirable and worthy goal. In this review, we will describe the recent advances in this field along with some of the technical hurdles encountered thus far.
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Affiliation(s)
- Howard G Damude
- Crop Genetics Research, DuPont Experimental Station, PO Box 80353, Wilmington, DE 19880-0353, USA
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Bentley R, Bennett JW. A Ferment of Fermentations: Reflections on the Production of Commodity Chemicals Using Microorganisms. ADVANCES IN APPLIED MICROBIOLOGY 2008; 63:1-32. [DOI: 10.1016/s0065-2164(07)00001-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Damude HG, Kinney AJ. Engineering Oilseed Plants for a Sustainable, Land-Based Source of Long Chain Polyunsaturated Fatty Acids. Lipids 2007; 42:179-85. [PMID: 17393224 DOI: 10.1007/s11745-007-3049-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
Numerous clinical studies have demonstrated the cardiovascular and mental health benefits of including very long chain omega-3 polyunsaturated fatty acids, namely eicospentaenoic acid (EPA) and docosohexaenoic acid (DHA) in the human diet. Certain fish oils can be a rich source of omega-3 long chain polyunsaturated fatty acids although processed marine oils are generally undesirable as food ingredients because of the associated objectionable flavors and contaminants that are difficult and cost-prohibitive to remove. Oilseed plants rich in omega-3 fatty acids, such as flax and walnut oils, contain only the 18-carbon omega-3 polyunsaturated fatty acid alpha-linolenic acid, which is poorly converted by the human body to EPA and DHA. It is now possible to engineer common omega-6 rich oilseeds such as soybean and canola to produce EPA and DHA and this has been the focus of a number of academic and industrial research groups. Recent advances and future prospects in the production of EPA and DHA in oilseed crops are discussed here.
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Affiliation(s)
- Howard G Damude
- Crop Genetics Research, DuPont Experimental Station, Wilmington, DE 19880-0353, USA
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Gokhale RS, Saxena P, Chopra T, Mohanty D. Versatile polyketide enzymatic machinery for the biosynthesis of complex mycobacterial lipids. Nat Prod Rep 2007; 24:267-77. [PMID: 17389997 DOI: 10.1039/b616817p] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The cell envelope of Mycobacterium tuberculosis (Mtb) is a treasure house of a variety of biologically active molecules with fascinating architectures. The decoding of the genetic blueprint of Mtb in recent years has provided the impetus for dissecting the metabolic pathways involved in the biosynthesis of lipidic metabolites. The focus of the Highlight is to emphasize the functional role of polyketide synthase (PKS) proteins in the biosynthesis of complex mycobacterial lipids. The catalytic as well as mechanistic versatility of PKS. in generating metabolic diversity and the significance of recently discovered fatty acyl-AMP ligases in establishing "biochemical crosstalk" between fatty acid synthases (FASs) and PKSs is described. The phenotypic heterogeneity and remodeling of the mycobacterial cell wall in its aetiopathogenesis is discussed.
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Affiliation(s)
- Rajesh S Gokhale
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110 067, India.
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29
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Keller NP, Turner G, Bennett JW. Fungal secondary metabolism — from biochemistry to genomics. Nat Rev Microbiol 2005; 3:937-47. [PMID: 16322742 DOI: 10.1038/nrmicro1286] [Citation(s) in RCA: 1066] [Impact Index Per Article: 56.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Much of natural product chemistry concerns a group of compounds known as secondary metabolites. These low-molecular-weight metabolites often have potent physiological activities. Digitalis, morphine and quinine are plant secondary metabolites, whereas penicillin, cephalosporin, ergotrate and the statins are equally well known fungal secondary metabolites. Although chemically diverse, all secondary metabolites are produced by a few common biosynthetic pathways, often in conjunction with morphological development. Recent advances in molecular biology, bioinformatics and comparative genomics have revealed that the genes encoding specific fungal secondary metabolites are clustered and often located near telomeres. In this review, we address some important questions, including which evolutionary pressures led to gene clustering, why closely related species produce different profiles of secondary metabolites, and whether fungal genomics will accelerate the discovery of new pharmacologically active natural products.
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Affiliation(s)
- Nancy P Keller
- University of Wisconsin-Madison, Department of Plant Pathology, 882 Russell Labs, 1630 Linden Drive, Madison, Wisconsin 53706, USA.
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30
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González-Lergier J, Broadbelt LJ, Hatzimanikatis V. Theoretical Considerations and Computational Analysis of the Complexity in Polyketide Synthesis Pathways. J Am Chem Soc 2005; 127:9930-8. [PMID: 15998100 DOI: 10.1021/ja051586y] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The emergence of antimicrobial resistance has led to an increase in research directed toward the engineering of novel polyketides. To date, less than 10 000 polyketide structures have been discovered experimentally; however, the theoretical analysis of polyketide biosynthesis performed suggests that over a billion possible structures can be synthesized. Polyketide synthesis, which involves the formation of a linear chain and its subsequent cyclization, is catalyzed by an enzyme complex called polyketide synthase (PKS). There are a number of variables in the linear chain synthesis controlled by the PKS: the number, identity, stereochemistry and sequence of the monomer units used in the elongation steps, and the degree of reduction that occurs after each of the condensation reactions. The theoretical analysis performed demonstrates that changes in these variables lead to the formation of different polyketide linear chains and, consequently, a high diversity of polyketide structures. The complexity in the number of possible structures led to the implementation of this system in BNICE, a computational framework that generates all possible biochemical pathways using a given set of enzyme reaction rules. This formulation allowed the analysis of the evolution of diversity in the synthesis mechanism and the construction of the pathway architecture of polyketide biosynthesis. It is expected that, after future implementation of the cyclization reactions, this framework can be used to identify all possible polyketides and their corresponding synthesis pathways. Consequently, this formulation would prove useful in guiding experimental approaches to engineer novel polyketides, a number of which will likely have medicinal properties.
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Affiliation(s)
- Joanna González-Lergier
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA
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31
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Burkholder JM, Gordon AS, Moeller PD, Law JM, Coyne KJ, Lewitus AJ, Ramsdell JS, Marshall HG, Deamer NJ, Cary SC, Kempton JW, Morton SL, Rublee PA. Demonstration of toxicity to fish and to mammalian cells by Pfiesteria species: comparison of assay methods and strains. Proc Natl Acad Sci U S A 2005; 102:3471-6. [PMID: 15728353 PMCID: PMC552923 DOI: 10.1073/pnas.0500168102] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Indexed: 11/18/2022] Open
Abstract
Toxicity and its detection in the dinoflagellate fish predators Pfiesteria piscicida and Pfiesteria shumwayae depend on the strain and the use of reliable assays. Two assays, standardized fish bioassays (SFBs) with juvenile fish and fish microassays (FMAs) with larval fish, were compared for their utility to detect toxic Pfiesteria. The comparison included strains with confirmed toxicity, negative controls (noninducible Pfiesteria strains and a related nontoxic cryptoperidiniopsoid dinoflagellate), and P. shumwayae strain CCMP2089, which previously had been reported as nontoxic. SFBs, standardized by using toxic Pfiesteria (coupled with tests confirming Pfiesteria toxin) and conditions conducive to toxicity expression, reliably detected actively toxic Pfiesteria, but FMAs did not. Pfiesteria toxin was found in fish- and algae-fed clonal Pfiesteria cultures, including CCMP2089, but not in controls. In contrast, noninducible Pfiesteria and cryptoperidiniopsoids caused no juvenile fish mortality in SFBs even at high densities, and low larval fish mortality by physical attack in FMAs. Filtrate from toxic strains of Pfiesteria spp. in bacteria-free media was cytotoxic. Toxicity was enhanced by bacteria and other prey, especially live fish. Purified Pfiesteria toxin extract adversely affected mammalian cells as well as fish, and it caused fish death at environmentally relevant cell densities. These data show the importance of testing multiple strains when assessing the potential for toxicity at the genus or species level, using appropriate culturing techniques and assays.
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Affiliation(s)
- Joann M Burkholder
- Center for Applied Aquatic Ecology and College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA. joann_burkholder.ncsu.edu
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Hoffmeister M, Piotrowski M, Nowitzki U, Martin W. Mitochondrial trans-2-enoyl-CoA reductase of wax ester fermentation from Euglena gracilis defines a new family of enzymes involved in lipid synthesis. J Biol Chem 2004; 280:4329-38. [PMID: 15569691 DOI: 10.1074/jbc.m411010200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Under anaerobiosis, Euglena gracilis mitochondria perform a malonyl-CoA independent synthesis of fatty acids leading to accumulation of wax esters, which serve as the sink for electrons stemming from glycolytic ATP synthesis and pyruvate oxidation. An important enzyme of this unusual pathway is trans-2-enoyl-CoA reductase (EC 1.3.1.44), which catalyzes reduction of enoyl-CoA to acyl-CoA. Trans-2-enoyl-CoA reductase from Euglena was purified 1700-fold to electrophoretic homogeneity and was active with NADH and NADPH as the electron donor. The active enzyme is a monomer with molecular mass of 44 kDa. The amino acid sequence of tryptic peptides determined by electrospray ionization mass spectrometry were used to clone the corresponding cDNA, which encoded a polypeptide that, when expressed in Escherichia coli and purified by affinity chromatography, possessed trans-2-enoyl-CoA reductase activity close to that of the enzyme purified from Euglena. Trans-2-enoyl-CoA reductase activity is present in mitochondria and the mRNA is expressed under aerobic and anaerobic conditions. Using NADH, the recombinant enzyme accepted crotonyl-CoA (km=68 microm) and trans-2-hexenoyl-CoA (km=91 microm). In the crotonyl-CoA-dependent reaction, both NADH (km=109 microm) or NADPH (km=119 microm) were accepted, with 2-3-fold higher specific activities for NADH relative to NADPH. Trans-2-enoyl-CoA reductase homologues were not found among other eukaryotes, but are present as hypothetical reading frames of unknown function in sequenced genomes of many proteobacteria and a few Gram-positive eubacteria, where they occasionally occur next to genes involved in fatty acid and polyketide biosynthesis. Trans-2-enoyl-CoA reductase assigns a biochemical activity, NAD(P)H-dependent acyl-CoA synthesis from enoyl-CoA, to one member of this gene family of previously unknown function.
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Affiliation(s)
- Meike Hoffmeister
- Institute of Botany III, University of Düsseldorf, D-40225 Düsseldorf, Germany
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Lim GE, Haygood MG. "Candidatus Endobugula glebosa," a specific bacterial symbiont of the marine bryozoan Bugula simplex. Appl Environ Microbiol 2004; 70:4921-9. [PMID: 15294832 PMCID: PMC492373 DOI: 10.1128/aem.70.8.4921-4929.2004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bryozoans Bugula neritina and Bugula simplex harbor bacteria in the pallial sinuses of their larvae as seen by electron microscopy. In B. neritina, the bacterial symbiont has been characterized as a gamma-proteobacterium, "Candidatus Endobugula sertula." "Candidatus E. sertula" has been implicated as the source of the bryostatins, polyketides that provide chemical defense to the host and are also being tested for use in human cancer treatments. In this study, the bacterial symbiont in B. simplex larvae was identified by 16S rRNA-targeted PCR and sequencing as a gamma-proteobacterium closely related to and forming a monophyletic group with "Candidatus E. sertula." In a fluorescence in situ hybridization, a 16S ribosomal DNA probe specific to the B. simplex symbiont hybridized to long rod-shaped bacteria in the pallial sinus of a B. simplex larva. The taxonomic status "Candidatus Endobugula glebosa" is proposed for the B. simplex larval symbiont. Degenerate polyketide synthase (PKS) primers amplified a gene fragment from B. simplex that closely matched a PKS gene fragment from the bryostatin PKS cluster. PCR surveys show that the symbiont and this PKS gene fragment are consistently and uniquely associated with B. simplex. Bryostatin activity assays and chemical analyses of B. simplex extracts reveal the presence of compounds similar to bryostatins. Taken together, these findings demonstrate a symbiosis in B. simplex that is similar and evolutionarily related to that in B. neritina.
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Affiliation(s)
- Grace E Lim
- Scripps Institution of Oceanography, Marine Biology Research Division, 0202, University of California, San Diego, La Jolla, CA 92093-0202, USA
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Abstract
Resistance to the drugs used in the treatment of many infectious diseases is increasing, while microbial infections are being found to be responsible for more life-threatening diseases than previously thought. Despite a large investment in the invention and application of high-throughput screening techniques involving miniaturization and automation, and a diverse array of strategies for designing and constructing various chemical libraries, relatively few new drugs have resulted. Natural products, however, have been a major source of drugs for centuries. Since some of them are produced by organisms as a result of selection in favour of improved defense against competing deleterious microorganisms, in principle they would be less likely to incur resistance. Furthermore, the production of those defensive secondary metabolites is inducible because their original function is a response to environmental challenges. Moreover, symbioses, co-habitation associations between two or more different species of organisms, are universal in nature, and the production of secondary metabolites by symbiotic microbes may be an important adaptation allowing microbes to affect their hosts. Therefore, co-culture strategies, using combinations of plant cell-pathogenic microbes, plant cell-endophytes (or symbionts), and symbiont-pathogenic microbes, based on the principles of chemical defense and the known mechanisms of organism interactions, may be an efficient general approach in the search for new anti-microbial drugs.
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Affiliation(s)
- Chunhua Lu
- The State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan and School of Life Science, Xiamen University, Xiamen P. R. China
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Buglino J, Onwueme KC, Ferreras JA, Quadri LEN, Lima CD. Crystal Structure of PapA5, a Phthiocerol Dimycocerosyl Transferase from Mycobacterium tuberculosis. J Biol Chem 2004; 279:30634-42. [PMID: 15123643 DOI: 10.1074/jbc.m404011200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyketide-associated protein A5 (PapA5) is an acyltransferase that is involved in production of phthiocerol and phthiodiolone dimycocerosate esters, a class of virulence-enhancing lipids produced by Mycobacterium tuberculosis. Structural analysis of PapA5 at 2.75-A resolution reveals a two-domain structure that shares unexpected similarity to structures of chloramphenicol acetyltransferase, dihydrolipoyl transacetylase, carnitine acetyltransferase, and VibH, a non-ribosomal peptide synthesis condensation enzyme. The PapA5 active site includes conserved histidine and aspartic acid residues that are critical to PapA5 acyltransferase activity. PapA5 catalyzes acyl transfer reactions on model substrates that contain long aliphatic carbon chains, and two hydrophobic channels were observed linking the PapA5 surface to the active site with properties consistent with these biochemical activities and substrate preferences. An additional alpha helix not observed in other acyltransferase structures blocks the putative entrance into the PapA5 active site, indicating that conformational changes may be associated with PapA5 activity. PapA5 represents the first structure solved for a protein involved in polyketide synthesis in Mycobacteria.
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Affiliation(s)
- John Buglino
- Structural Biology Program, Sloan-Kettering Institute, New York, New York 10021, USA
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Onwueme KC, Ferreras JA, Buglino J, Lima CD, Quadri LEN. Mycobacterial polyketide-associated proteins are acyltransferases: proof of principle with Mycobacterium tuberculosis PapA5. Proc Natl Acad Sci U S A 2004; 101:4608-13. [PMID: 15070765 PMCID: PMC384794 DOI: 10.1073/pnas.0306928101] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2003] [Indexed: 11/18/2022] Open
Abstract
Mycobacterium tuberculosis (Mt) produces complex virulence-enhancing lipids with scaffolds consisting of phthiocerol and phthiodiolone dimycocerosate esters (PDIMs). Sequence analysis suggested that PapA5, a so-called polyketide-associated protein (Pap) encoded in the PDIM synthesis gene cluster, as well as PapA5 homologs found in Mt and other species, are a subfamily of acyltransferases. Studies with recombinant protein confirmed that PapA5 is an acyltransferase [corrected]. Deletion analysis in Mt demonstrated that papA5 is required for PDIM synthesis. We propose that PapA5 catalyzes diesterification of phthiocerol and phthiodiolone with mycocerosate. These studies present the functional characterization of a Pap and permit inferences regarding roles of other Paps in the synthesis of complex lipids, including the antibiotic rifamycin.
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Affiliation(s)
- Kenolisa C Onwueme
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA
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Kroken S, Glass NL, Taylor JW, Yoder OC, Turgeon BG. Phylogenomic analysis of type I polyketide synthase genes in pathogenic and saprobic ascomycetes. Proc Natl Acad Sci U S A 2003; 100:15670-5. [PMID: 14676319 PMCID: PMC307626 DOI: 10.1073/pnas.2532165100] [Citation(s) in RCA: 375] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Fungal type I polyketides (PKs) are synthesized by PK synthases (PKSs) and include well known secondary metabolites such as the anticholesterol drug lovastatin and the potent natural carcinogen aflatoxin. Other type I PKs are known to be virulence factors for some plant pathogens and pigments such as melanin. In this study, a phylogenomic approach was used to investigate the origin and diversity of fungal genes encoding putative PKSs that are predicted to synthesize type I PKs. The resulting genealogy, constructed by using the highly conserved PKS ketosynthase (KS) domain, indicated that: (i). Species within subphylum Pezizomycotina (phylum Ascomycota) but not early diverging ascomycetes, like Saccharomyces cerevisiae (Saccharomycotina) or Schizosaccharomyces pombe (Taphrinomycotina), had large numbers (7-25) of PKS genes. (ii). Bacteria and fungi had separate groups of PKS genes; the few exceptions are the likely result of horizontal gene transfer from bacteria to various sublineages of fungi. (iii). The bulk of genes encoding fungal PKSs fell into eight groups. Four groups were predicted to synthesize variously reduced PKs, and four groups were predicted to make unreduced PKs. (iv). Species within different classes of Pezizomycotina shared the same groups of PKS genes. (v). Different fungal genomes shared few putative orthologous PKS genes, even between closely related genomes in the same class or genus. (vi) The discontinuous distributions of orthologous PKSs among fungal species can be explained by gene duplication, divergence, and gene loss; horizontal gene transfer among fungi does not need to be invoked.
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Affiliation(s)
- Scott Kroken
- Torrey Mesa Research Institute, Syngenta, 3115 Merryfield Row, San Diego, CA 92121, USA
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38
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Abstract
Mycotoxins are secondary metabolites produced by microfungi that are capable of causing disease and death in humans and other animals. Because of their pharmacological activity, some mycotoxins or mycotoxin derivatives have found use as antibiotics, growth promotants, and other kinds of drugs; still others have been implicated as chemical warfare agents. This review focuses on the most important ones associated with human and veterinary diseases, including aflatoxin, citrinin, ergot akaloids, fumonisins, ochratoxin A, patulin, trichothecenes, and zearalenone.
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Affiliation(s)
- J W Bennett
- Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana 70118, USA.
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39
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Abstract
The chapter informs about different types of antibiotics, their structure, biosynthesis and their regulation. Industrial cultivation and isolation of antibiotics is described in the chapter. Search for microorganisms producing antibiotics and preparation of high-producing strains is described. Resistance against antibiotics in producing microorganisms and pathogens is discussed.
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Affiliation(s)
- V Bĕhal
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague, Czech Republic.
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40
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Affiliation(s)
- M F Dutton
- Faculty of Health Sciences, Technikon Witwatersrand, P.O. Box 17011, Doornfontein, Gauteng, 2028, South Africa
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41
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Velkov T, Lawen A. Non-ribosomal peptide synthetases as technological platforms for the synthesis of highly modified peptide bioeffectors – Cyclosporin synthetase as a complex example. BIOTECHNOLOGY ANNUAL REVIEW 2003; 9:151-97. [PMID: 14650927 DOI: 10.1016/s1387-2656(03)09002-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Many microbial peptide secondary metabolites possess important medicinal properties, of which the immunosuppressant cyclosporin A is an example. The enormous structural and functional diversity of these low-molecular weight peptides is attributable to their mode of biosynthesis. Peptide secondary metabolites are assembled non-ribosomally by multi-functional enzymes, termed non-ribosomal peptide synthetases. These systems consist of a multi-modular arrangement of the functional domains responsible for the catalysis of the partial reactions of peptide assembly. The extensive homology shared among NRPS systems allows for the generalisation of the knowledge garnered from studies of systems of diverse origins. In this review we shall focus the contemporary knowledge of non-ribosomal peptide biosynthesis on the structure and function of the cyclosporin biosynthetic system, with some emphasis on the re-direction of the biosynthetic potential of this system by combinatorial approaches.
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Affiliation(s)
- Tony Velkov
- Monash University, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, P.O. Box 13D, Melbourne, Victoria 3800, Australia
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42
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Ostash BO, Fedorenko VO. Gene engineering of novel polyketide antibiotics producers. ACTA ACUST UNITED AC 2002. [DOI: 10.7124/bc.000629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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43
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Coates A, Hu Y, Bax R, Page C. The future challenges facing the development of new antimicrobial drugs. Nat Rev Drug Discov 2002; 1:895-910. [PMID: 12415249 DOI: 10.1038/nrd940] [Citation(s) in RCA: 406] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The emergence of resistance to antibacterial agents is a pressing concern for human health. New drugs to combat this problem are therefore in great demand, but as past experience indicates, the time for resistance to new drugs to develop is often short. Conventionally, antibacterial drugs have been developed on the basis of their ability to inhibit bacterial multiplication, and this remains at the core of most approaches to discover new antibacterial drugs. Here, we focus primarily on an alternative novel strategy for antibacterial drug development that could potentially alleviate the current situation of drug resistance--targeting non-multiplying latent bacteria, which prolong the duration of antimicrobial chemotherapy and so might increase the rate of development of resistance.
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Affiliation(s)
- Anthony Coates
- Department of Medical Microbiology, St George's Hospital Medical School, Cranmer Terrace, London SW17 ORE, UK.
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44
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Abstract
Polyunsaturated fatty acids have crucial roles in membrane biology and signaling processes in most living organisms. However, it is only recently that molecular genetic approaches have allowed detailed studies of the enzymes involved in their synthesis. New evidence has revealed a range of pathways in different organisms. These include a complex sequence for synthesis of docosahexaenoic acid (22:6) in mammals and a polyketide synthase pathway in marine microbes.
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Affiliation(s)
- James G Wallis
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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45
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Kato Y, Bai L, Xue Q, Revill WP, Yu TW, Floss HG. Functional expression of genes involved in the biosynthesis of the novel polyketide chain extension unit, methoxymalonyl-acyl carrier protein, and engineered biosynthesis of 2-desmethyl-2-methoxy-6-deoxyerythronolide B. J Am Chem Soc 2002; 124:5268-9. [PMID: 11996558 DOI: 10.1021/ja0127483] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A subcluster of five genes, asm13-17, from the ansamitocin biosynthetic gene cluster of Actinosynnema pretiosum was coexpressed in Streptomyces lividans with the genes encoding the 6-deoxyerythronolide B (6-DEB) synthase from Saccharopolyspora erythraea, in which the methylmalonate-specifying AT6 domain had been replaced by the methoxymalonate-specifying AT8 domain from the FK520 cluster of Streptomyces hygroscopicus. The engineered strain produced the predicted product, 2-desmethyl-2-methoxy-DEB, instead of 6-DEB and 2-desmethyl-6-DEB, which were formed in the absence of the asm13-17 cassette, indicating that asm13-17 are sufficient for synthesis of this unusual chain extension unit. Deletion of asm17, encoding a methyltransferase, from the cassette gave 6-DEB instead of its hydroxy analogue, indicating that methylation of the extender unit is required for its incorporation.
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Affiliation(s)
- Yasuo Kato
- Department of Chemistry, Box 351700, University of Washington, Seattle, Washington 98195-1700, USA
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46
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Schmidt-Dannert C. Directed evolution of single proteins, metabolic pathways, and viruses. Biochemistry 2001; 40:13125-36. [PMID: 11683620 DOI: 10.1021/bi011310c] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- C Schmidt-Dannert
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota 55126, USA.
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47
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Metz JG, Roessler P, Facciotti D, Levering C, Dittrich F, Lassner M, Valentine R, Lardizabal K, Domergue F, Yamada A, Yazawa K, Knauf V, Browse J. Production of polyunsaturated fatty acids by polyketide synthases in both prokaryotes and eukaryotes. Science 2001; 293:290-3. [PMID: 11452122 DOI: 10.1126/science.1059593] [Citation(s) in RCA: 474] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Polyunsaturated fatty acids (PUFAs) are essential membrane components in higher eukaryotes and are the precursors of many lipid-derived signaling molecules. Here, pathways for PUFA synthesis are described that do not require desaturation and elongation of saturated fatty acids. These pathways are catalyzed by polyketide synthases (PKSs) that are distinct from previously recognized PKSs in both structure and mechanism. Generation of cis double bonds probably involves position-specific isomerases; such enzymes might be useful in the production of new families of antibiotics. It is likely that PUFA synthesis in cold marine ecosystems is accomplished in part by these PKS enzymes.
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Affiliation(s)
- J G Metz
- Omega Tech, 4909 Nautilus Court North, Boulder, CO 80301-3242, USA.
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48
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Chotani G, Dodge T, Hsu A, Kumar M, LaDuca R, Trimbur D, Weyler W, Sanford K. The commercial production of chemicals using pathway engineering. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1543:434-455. [PMID: 11150618 DOI: 10.1016/s0167-4838(00)00234-x] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Integration of metabolic pathway engineering and fermentation production technologies is necessary for the successful commercial production of chemicals. The 'toolbox' to do pathway engineering is ever expanding to enable mining of biodiversity, to maximize productivity, enhance carbon efficiency, improve product purity, expand product lines, and broaden markets. Functional genomics, proteomics, fluxomics, and physiomics are complementary to pathway engineering, and their successful applications are bound to multiply product turnover per cell, channel carbon efficiently, shrink the size of factories (i.e., reduce steel in the ground), and minimize product development cycle times to bring products to market.
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Affiliation(s)
- G Chotani
- Genencor International, 925 Page Mill Road, 94304, Palo Alto, CA, USA
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49
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Jez JM, Noel JP. Mechanism of chalcone synthase. pKa of the catalytic cysteine and the role of the conserved histidine in a plant polyketide synthase. J Biol Chem 2000; 275:39640-6. [PMID: 11006298 DOI: 10.1074/jbc.m008569200] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyketide synthases (PKS) assemble structurally diverse natural products using a common mechanistic strategy that relies on a cysteine residue to anchor the polyketide during a series of decarboxylative condensation reactions that build the final reaction product. Crystallographic and functional studies of chalcone synthase (CHS), a plant-specific PKS, indicate that a cysteine-histidine pair (Cys(164)-His(303)) forms part of the catalytic machinery. Thiol-specific inactivation and the pH dependence of the malonyl-CoA decarboxylation reaction were used to evaluate the potential interaction between these two residues. Inactivation of CHS by iodoacetamide and iodoacetic acid targets Cys(164) in a pH-dependent manner (pK(a) = 5.50). The acidic pK(a) of Cys(164) suggests that an ionic interaction with His(303) stabilizes the thiolate anion. Consistent with this assertion, substitution of a glutamine for His(303) maintains catalytic activity but shifts the pK(a) of the thiol to 6.61. Although the H303A mutant was catalytically inactive, the pH-dependent incorporation of [(14)C]iodoacetamide into this mutant exhibits a pK(a) = 7.62. Subsequent analysis of the pH dependence of the malonyl-CoA decarboxylation reaction catalyzed by wild-type CHS and the H303Q and C164A mutants also supports the presence of an ion pair at the CHS active site. Structural and sequence conservation of a cysteine-histidine pair in the active sites of other PKS implies that a thiolate-imidazolium ion pair plays a central role in polyketide biosynthesis.
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Affiliation(s)
- J M Jez
- Structural Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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50
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Jez JM, Austin MB, Ferrer J, Bowman ME, Schröder J, Noel JP. Structural control of polyketide formation in plant-specific polyketide synthases. CHEMISTRY & BIOLOGY 2000; 7:919-30. [PMID: 11137815 DOI: 10.1016/s1074-5521(00)00041-7] [Citation(s) in RCA: 212] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Polyketide synthases (PKSs) generate molecular diversity by utilizing different starter molecules and by controlling the final length of the polyketide. Although exploitation of this mechanistic variability has produced novel polyketides, the structural foundation of this versatility is unclear. Plant-specific PKSs are essential for the biosynthesis of anti-microbial phytoalexins, anthocyanin floral pigments, and inducers of Rhizobium nodulation genes. 2-Pyrone synthase (2-PS) and chalcone synthase (CHS) are plant-specific PKSs that share 74% amino acid sequence identity. 2-PS forms the triketide methylpyrone from an acetyl-CoA starter molecule and two malonyl-CoAs. CHS uses a p-coumaroyl-CoA starter molecule and three malonyl-CoAs to produce the tetraketide chalcone. Our goal was to elucidate the molecular basis of starter molecule selectivity and control of polyketide length in this class of PKS. RESULTS The 2.05 A resolution crystal structure of 2-PS complexed with the reaction intermediate acetoacetyl-CoA was determined by molecular replacement. 2-PS and CHS share a common three-dimensional fold, a set of conserved catalytic residues, and similar CoA binding sites. However, the active site cavity of 2-PS is smaller than the cavity in CHS. Of the 28 residues lining the 2-PS initiation/elongation cavity, four positions vary in CHS. Point mutations at three of these positions in CHS (T197L, G256L, and S338I) altered product formation. Combining these mutations in a CHS triple mutant (T197L/G256L/S338I) yielded an enzyme that was functionally identical to 2-PS. CONCLUSIONS Structural and functional characterization of 2-PS together with generation of a CHS mutant with an initiation/elongation cavity analogous to 2-PS demonstrates that cavity volume influences the choice of starter molecule and controls the final length of the polyketide. These results provide a structural basis for control of polyketide length in other PKSs, and suggest strategies for further increasing the scope of polyketide biosynthetic diversity.
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Affiliation(s)
- J M Jez
- Structural Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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