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Ding X, Wang H, Huang S, Zhang H, Chen H, Chen P, Wang Y, Yang Z, Wang Y, Peng S, Dai H, Mei W. Molecular evolution and characterization of type III polyketide synthase gene family in Aquilaria sinensis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 210:108571. [PMID: 38604011 DOI: 10.1016/j.plaphy.2024.108571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 02/24/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
2-(2-Phenylethyl) chromone (PEC) and its derivatives are markers of agarwood formation and are also related to agarwood quality. However, the biosynthetic and regulatory mechanisms of PECs still remain mysterious. Several studies suggested that type III polyketide synthases (PKSs) contribute to PEC biosynthesis in Aquilaria sinensis. Furthermore, systematic studies on the evolution of PKSs in A. sinensis have rarely been reported. Herein, we comprehensively analyzed PKS genes from 12 plant genomes and characterized the AsPKSs in detail. A unique branch contained only AsPKS members was identified through evolutionary analysis, including AsPKS01 that was previously indicated to participate in PEC biosynthesis. AsPKS07 and AsPKS08, two tandem-duplicated genes of AsPKS01 and lacking orthologous genes in evolutionary models, were selected for their transient expression in the leaves of Nicotiana benthamiana. Subsequently, PECs were detected in the extracts of N. benthamiana leaves, suggesting that AsPKS07 and AsPKS08 promote PEC biosynthesis. The interaction between the promoters of AsPKS07, AsPKS08 and five basic leucine zippers (bZIPs) from the S subfamily indicated that their transcripts could be regulated by these transcription factors (TFs) and might further contribute to PECs biosynthesis in A. sinensis. Our findings provide valuable insights into the molecular evolution of the PKS gene family in A. sinensis and serve as a foundation for advancing PEC production through the bioengineering of gene clusters. Ultimately, this contribution is expected to shed light on the mechanism underlying agarwood formation.
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Affiliation(s)
- Xupo Ding
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.
| | - Hao Wang
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Shengzhuo Huang
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Hao Zhang
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Huiqin Chen
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Pengwei Chen
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Yuguang Wang
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Zhuo Yang
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Yali Wang
- International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Shiqing Peng
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China
| | - Haofu Dai
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.
| | - Wenli Mei
- Key Laboratory of Research and Development of Natural Product from Li Folk Medicine of Hainan Province, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; International Joint Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China; Hainan Engineering Research Center of Agarwood, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, 571101, China.
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Deciphering the Binding Interactions between Acinetobacter baumannii ACP and β-ketoacyl ACP Synthase III to Improve Antibiotic Targeting Using NMR Spectroscopy. Int J Mol Sci 2021; 22:ijms22073317. [PMID: 33805050 PMCID: PMC8036411 DOI: 10.3390/ijms22073317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/20/2021] [Accepted: 03/21/2021] [Indexed: 11/17/2022] Open
Abstract
Fatty acid synthesis is essential for bacterial viability. Thus, fatty acid synthases (FASs) represent effective targets for antibiotics. Nevertheless, multidrug-resistant bacteria, including the human opportunistic bacteria, Acinetobacter baumannii, are emerging threats. Meanwhile, the FAS pathway of A. baumannii is relatively unexplored. Considering that acyl carrier protein (ACP) has an important role in the delivery of fatty acyl intermediates to other FAS enzymes, we elucidated the solution structure of A. baumannii ACP (AbACP) and, using NMR spectroscopy, investigated its interactions with β-ketoacyl ACP synthase III (AbKAS III), which initiates fatty acid elongation. The results show that AbACP comprises four helices, while Ca2+ reduces the electrostatic repulsion between acid residues, and the unconserved F47 plays a key role in thermal stability. Moreover, AbACP exhibits flexibility near the hydrophobic cavity entrance from D59 to T65, as well as in the α1α2 loop region. Further, F29 and A69 participate in slow exchanges, which may be related to shuttling of the growing acyl chain. Additionally, electrostatic interactions occur between the α2 and α3-helix of ACP and AbKAS III, while the hydrophobic interactions through the ACP α2-helix are seemingly important. Our study provides insights for development of potent antibiotics capable of inhibiting A. baumannii FAS protein–protein interactions.
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Sulpizio A, Crawford CEW, Koweek RS, Charkoudian LK. Probing the structure and function of acyl carrier proteins to unlock the strategic redesign of type II polyketide biosynthetic pathways. J Biol Chem 2021; 296:100328. [PMID: 33493513 PMCID: PMC7949117 DOI: 10.1016/j.jbc.2021.100328] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 02/04/2023] Open
Abstract
Type II polyketide synthases (PKSs) are protein assemblies, encoded by biosynthetic gene clusters in microorganisms, that manufacture structurally complex and pharmacologically relevant molecules. Acyl carrier proteins (ACPs) play a central role in biosynthesis by shuttling malonyl-based building blocks and polyketide intermediates to catalytic partners for chemical transformations. Because ACPs serve as central hubs in type II PKSs, they can also represent roadblocks to successfully engineering synthases capable of manufacturing 'unnatural natural products.' Therefore, understanding ACP conformational dynamics and protein interactions is essential to enable the strategic redesign of type II PKSs. However, the inherent flexibility and transience of ACP interactions pose challenges to gaining insight into ACP structure and function. In this review, we summarize how the application of chemical probes and molecular dynamic simulations has increased our understanding of the structure and function of type II PKS ACPs. We also share how integrating these advances in type II PKS ACP research with newfound access to key enzyme partners, such as the ketosynthase-chain length factor, sets the stage to unlock new biosynthetic potential.
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Affiliation(s)
- Ariana Sulpizio
- Department of Chemistry, Haverford College, Haverford, Pennsylvania, USA
| | | | - Rebecca S Koweek
- Department of Chemistry, Haverford College, Haverford, Pennsylvania, USA
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4
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Zhang Y, Ye Q, Ponomareva LV, Cao Y, Liu Y, Cui Z, Van Lanen SG, Voss SR, She QB, Thorson JS. Total synthesis of griseusins and elucidation of the griseusin mechanism of action. Chem Sci 2019; 10:7641-7648. [PMID: 31583069 PMCID: PMC6755659 DOI: 10.1039/c9sc02289a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 06/26/2019] [Indexed: 12/15/2022] Open
Abstract
An efficient divergent synthesis of griseusins enabled SAR studies, mechanistic elucidation and evaluation in an axolotl tail regeneration model.
A divergent modular strategy for the enantioselective total synthesis of 12 naturally-occurring griseusin type pyranonaphthoquinones and 8 structurally-similar analogues is described. Key synthetic highlights include Cu-catalyzed enantioselective boration–hydroxylation and hydroxyl-directed C–H olefination to afford the central pharmacophore followed by epoxidation–cyclization and maturation via diastereoselective reduction and regioselective acetylation. Structural revision of griseusin D and absolute structural assignment of 2a,8a-epoxy-epi-4′-deacetyl griseusin B are also reported. Subsequent mechanistic studies establish, for the first time, griseusins as potent inhibitors of peroxiredoxin 1 (Prx1) and glutaredoxin 3 (Grx3). Biological evaluation, including comparative cancer cell line cytotoxicity and axolotl embryo tail inhibition studies, highlights the potential of griseusins as potent molecular probes and/or early stage leads in cancer and regenerative biology.
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Affiliation(s)
- Yinan Zhang
- Jiangsu Key Laboratory for Functional Substances of Chinese Medicine , School of Pharmacy , Nanjing University of Chinese Medicine , Nanjing , Jiangsu 210023 , China.,Center for Pharmaceutical Research and Innovation , University of Kentucky , Lexington , KY 40536 , USA.,College of Pharmacy , University of Kentucky , Lexington , KY 40536 , USA .
| | - Qing Ye
- Markey Cancer Center , Department of Pharmacology and Nutritional Sciences , College of Medicine , University of Kentucky , Lexington , KY 40536 , USA .
| | - Larissa V Ponomareva
- Center for Pharmaceutical Research and Innovation , University of Kentucky , Lexington , KY 40536 , USA.,College of Pharmacy , University of Kentucky , Lexington , KY 40536 , USA .
| | - Yanan Cao
- Markey Cancer Center , Department of Pharmacology and Nutritional Sciences , College of Medicine , University of Kentucky , Lexington , KY 40536 , USA .
| | - Yang Liu
- Center for Pharmaceutical Research and Innovation , University of Kentucky , Lexington , KY 40536 , USA.,College of Pharmacy , University of Kentucky , Lexington , KY 40536 , USA .
| | - Zheng Cui
- College of Pharmacy , University of Kentucky , Lexington , KY 40536 , USA .
| | - Steven G Van Lanen
- College of Pharmacy , University of Kentucky , Lexington , KY 40536 , USA .
| | - S Randal Voss
- Department of Neuroscience , Spinal Cord and Brain Injury Research Center , Ambystoma Genetic Stock Center , University of Kentucky , Lexington , KY 40536 , USA
| | - Qing-Bai She
- Markey Cancer Center , Department of Pharmacology and Nutritional Sciences , College of Medicine , University of Kentucky , Lexington , KY 40536 , USA .
| | - Jon S Thorson
- Center for Pharmaceutical Research and Innovation , University of Kentucky , Lexington , KY 40536 , USA.,College of Pharmacy , University of Kentucky , Lexington , KY 40536 , USA .
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5
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Sabatini M, Comba S, Altabe S, Recio-Balsells AI, Labadie GR, Takano E, Gramajo H, Arabolaza A. Biochemical characterization of the minimal domains of an iterative eukaryotic polyketide synthase. FEBS J 2018; 285:4494-4511. [PMID: 30300504 PMCID: PMC6334511 DOI: 10.1111/febs.14675] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/03/2018] [Accepted: 09/25/2018] [Indexed: 01/19/2023]
Abstract
Iterative type I polyketide synthases (PKS) are megaenzymes essential to the biosynthesis of an enormously diverse array of bioactive natural products. Each PKS contains minimally three functional domains, β-ketosynthase (KS), acyltransferase (AT), and acyl carrier protein (ACP), and a subset of reducing domains such as ketoreductase (KR), dehydratase (DH), and enoylreductase (ER). The substrate selection, condensation reactions, and β-keto processing of the polyketide growing chain are highly controlled in a programmed manner. However, the structural features and mechanistic rules that orchestrate the iterative cycles, processing domains functionality, and chain termination in this kind of megaenzymes are often poorly understood. Here, we present a biochemical and functional characterization of the KS and the AT domains of a PKS from the mallard duck Anas platyrhynchos (ApPKS). ApPKS belongs to an animal PKS family phylogenetically more related to bacterial PKS than to metazoan fatty acid synthases. Through the dissection of the ApPKS enzyme into mono- to didomain fragments and its reconstitution in vitro, we determined its substrate specificity toward different starters and extender units. ApPKS AT domain can effectively transfer acetyl-CoA and malonyl-CoA to the ApPKS ACP stand-alone domain. Furthermore, the KS and KR domains, in the presence of Escherichia coli ACP, acetyl-CoA, and malonyl-CoA, showed the ability to catalyze the chain elongation and the β-keto reduction steps necessary to yield a 3-hydroxybutyryl-ACP derivate. These results provide new insights into the catalytic efficiency and specificity of this uncharacterized family of PKSs.
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Affiliation(s)
- Martin Sabatini
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Argentina
| | - Santiago Comba
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Argentina
| | - Silvia Altabe
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Argentina
| | - Alejandro I Recio-Balsells
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Química de Rosario (IQUIR-CONICET), Universidad Nacional de Rosario, Argentina
| | - Guillermo R Labadie
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Química de Rosario (IQUIR-CONICET), Universidad Nacional de Rosario, Argentina
| | - Eriko Takano
- Manchester Centre of Fine and Specialty Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology (MIB), University of Manchester, UK
| | - Hugo Gramajo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Argentina
| | - Ana Arabolaza
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Argentina
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Jackson DR, Shakya G, Patel AB, Mohammed LY, Vasilakis K, Wattana-Amorn P, Valentic TR, Milligan JC, Crump MP, Crosby J, Tsai SC. Structural and Functional Studies of the Daunorubicin Priming Ketosynthase DpsC. ACS Chem Biol 2018; 13:141-151. [PMID: 29161022 DOI: 10.1021/acschembio.7b00551] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Daunorubicin is a type II polyketide, one of a large class of polyaromatic natural products with anticancer, antibiotic, and antiviral activity. Type II polyketides are formed by the assembly of malonyl-CoA building blocks, though in rare cases, biosynthesis is initiated by the incorporation of a nonmalonyl derived starter unit, which adds molecular diversity to the poly-β-ketone backbone. Priming mechanisms for the transfer of novel starter units onto polyketide synthases (PKS) are still poorly understood. Daunorubicin biosynthesis incorporates a unique propionyl starter unit thought to be selected for by a subclass ("DpsC type") of priming ketosynthases (KS III). To date, however, no structural information exists for this subclass of KS III enzymes. Although selectivity for self-acylation with propionyl-CoA has previously been implied, we demonstrate that DpsC shows no discrimination for self-acylation or acyl-transfer to the cognate acyl carrier protein, DpsG with short acyl-CoAs. We present five crystal structures of DpsC, including apo-DpsC, acetyl-DpsC, propionyl-DpsC, butyryl-DpsC, and a cocrystal of DpsC with a nonhydrolyzable phosphopantetheine (PPant) analogue. The DpsC crystal structures reveal the architecture of the active site, the molecular determinants for catalytic activity and homology to O-malonyl transferases, but also indicate distinct differences. These results provide a structural basis for rational engineering of starter unit selection in type II polyketide synthases.
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Affiliation(s)
- David R. Jackson
- Department
of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical
Sciences, University of California, Irvine, Irvine, California 92697, United States
| | - Gaurav Shakya
- Department
of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical
Sciences, University of California, Irvine, Irvine, California 92697, United States
| | - Avinash B. Patel
- Department
of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical
Sciences, University of California, Irvine, Irvine, California 92697, United States
| | - Lina Y. Mohammed
- School
of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Kostas Vasilakis
- School
of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Pakorn Wattana-Amorn
- School
of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Timothy R. Valentic
- Department
of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical
Sciences, University of California, Irvine, Irvine, California 92697, United States
| | - Jacob C. Milligan
- Department
of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical
Sciences, University of California, Irvine, Irvine, California 92697, United States
| | - Matthew P. Crump
- School
of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - John Crosby
- School
of Chemistry, Cantock’s Close, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Shiou-Chuan Tsai
- Department
of Molecular Biology and Biochemistry, Chemistry, and Pharmaceutical
Sciences, University of California, Irvine, Irvine, California 92697, United States
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Du D, Katsuyama Y, Shin-ya K, Ohnishi Y. Reconstitution of a Type II Polyketide Synthase that Catalyzes Polyene Formation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201709636] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Danyao Du
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Yohei Katsuyama
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Kazuo Shin-ya
- National Institute of Advanced Industrial Science and Technology (AIST); 2-4-7, Aomi Koto-ku Tokyo 135-0064 Japan
| | - Yasuo Ohnishi
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
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8
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Du D, Katsuyama Y, Shin-ya K, Ohnishi Y. Reconstitution of a Type II Polyketide Synthase that Catalyzes Polyene Formation. Angew Chem Int Ed Engl 2018; 57:1954-1957. [DOI: 10.1002/anie.201709636] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/11/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Danyao Du
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Yohei Katsuyama
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
| | - Kazuo Shin-ya
- National Institute of Advanced Industrial Science and Technology (AIST); 2-4-7, Aomi Koto-ku Tokyo 135-0064 Japan
| | - Yasuo Ohnishi
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences; The University of Tokyo; 1-1-1 Yayoi Bunkyo-ku Tokyo 113-8657 Japan
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9
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Dong X, Bailey CD, Williams C, Crosby J, Simpson TJ, Willis CL, Crump MP. Recognition of extended linear and cyclised polyketide mimics by a type II acyl carrier protein. Chem Sci 2016; 7:1779-1785. [PMID: 28936328 PMCID: PMC5595124 DOI: 10.1039/c5sc03864b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/08/2015] [Indexed: 12/02/2022] Open
Abstract
Polyketides are secondary metabolites which display both valuable pharmaceutical and agrochemical properties. Biosynthesis is performed by polyketide synthases (PKSs), and the acyl carrier protein (ACP), a small acidic protein, that transports the growing polyketide chain and is essential for activity. Here we report the synthesis of two aromatic probes and a linear octaketide mimic that have been tethered to actinorhodin ACP. These experiments were aimed at probing the ACP's capacity to sequester a non-polar versus a phenolic aromatic ring (that more closely mimics a polyketide intermediate) as well as investigations with extended polyketide chain surrogates. The binding of these mimics has been assessed using high-resolution solution NMR studies and high-resolution structure determination. These results reveal that surprisingly a PKS ACP is able to bind and sequester a bulky non-polar substrate containing an aromatic ring in a fatty acid type binding mode, but the introduction of even a small degree of polarity favours a markedly different association at a surface site that is distinct from that employed by fatty acid ACPs.
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Affiliation(s)
- Xu Dong
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , UK . ;
| | - Christopher D Bailey
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , UK . ;
| | - Christopher Williams
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , UK . ;
| | - John Crosby
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , UK . ;
| | - Thomas J Simpson
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , UK . ;
| | - Christine L Willis
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , UK . ;
| | - Matthew P Crump
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , UK . ;
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10
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Liu C, Zhu J, Li Y, Zhang J, Lu C, Wang H, Shen Y. In Vitro Reconstitution of a PKS Pathway for the Biosynthesis of Galbonolides inStreptomycessp. LZ35. Chembiochem 2015; 16:998-1007. [DOI: 10.1002/cbic.201500017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Indexed: 01/13/2023]
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11
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Li Y, Chen H, Ding Y, Xie Y, Wang H, Cerny RL, Shen Y, Du L. Iterative assembly of two separate polyketide chains by the same single-module bacterial polyketide synthase in the biosynthesis of HSAF. Angew Chem Int Ed Engl 2014; 53:7524-7530. [PMID: 24890524 PMCID: PMC4107061 DOI: 10.1002/anie.201403500] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Indexed: 12/29/2022]
Abstract
Antifungal HSAF (heat-stable antifungal factor, dihydromaltophilin) is a polycyclic tetramate macrolactam from the biocontrol agent Lysobacter enzymogenes. Its biosynthetic gene cluster contains only a single-module polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS), although two separate hexaketide chains are required to assemble the skeleton. To address the unusual biosynthetic mechanism, we expressed the biosynthetic genes in two "clean" strains of Streptomyces and showed the production of HSAF analogues and a polyene tetramate intermediate. We then expressed the PKS module in Escherichia coli and purified the enzyme. Upon incubation of the enzyme with acyl-coenzyme A and reduced nicotinamide adenine dinucleotide phosphate (NADPH), a polyene was detected in the tryptic acyl carrier protein (ACP). Finally, we incubated the polyene-PKS with the NRPS module in the presence of ornithine and adenosine triphosphate (ATP), and we detected the same polyene tetramate as that in Streptomyces transformed with the PKS-NRPS alone. Together, our results provide evidence for an unusual iterative biosynthetic mechanism for bacterial polyketide-peptide natural products.
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Affiliation(s)
- Yaoyao Li
- Key Laboratory of Chemical Biology, School of Pharmaceutical Sciences, Shandong University, Jinan 250100, China
| | - Haotong Chen
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Yanjiao Ding
- Key Laboratory of Chemical Biology, School of Pharmaceutical Sciences, Shandong University, Jinan 250100, China
| | - Yunxuan Xie
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Haoxin Wang
- Key Laboratory of Chemical Biology, School of Pharmaceutical Sciences, Shandong University, Jinan 250100, China; State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan 250100, China
| | - Ronald L. Cerny
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Yuemao Shen
- Key Laboratory of Chemical Biology, School of Pharmaceutical Sciences, Shandong University, Jinan 250100, China; State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan 250100, China
| | - Liangcheng Du
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
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12
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Li Y, Chen H, Ding Y, Xie Y, Wang H, Cerny RL, Shen Y, Du L. Iterative Assembly of Two Separate Polyketide Chains by the Same Single-Module Bacterial Polyketide Synthase in the Biosynthesis of HSAF. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201403500] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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13
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Ishikawa F, Haushalter RW, Lee DJ, Finzel K, Burkart MD. Sulfonyl 3-alkynyl pantetheinamides as mechanism-based cross-linkers of acyl carrier protein dehydratase. J Am Chem Soc 2013; 135:8846-9. [PMID: 23718183 DOI: 10.1021/ja4042059] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Acyl carrier proteins (ACPs) play a central role in acetate biosynthetic pathways, serving as tethers for substrates and growing intermediates. Activity and structural studies have highlighted the complexities of this role, and the protein-protein interactions of ACPs have recently come under scrutiny as a regulator of catalysis. As existing methods to interrogate these interactions have fallen short, we have sought to develop new tools to aid their study. Here we describe the design, synthesis, and application of pantetheinamides that can cross-link ACPs with catalytic β-hydroxy-ACP dehydratase (DH) domains by means of a 3-alkynyl sulfone warhead. We demonstrate this process by application to the Escherichia coli fatty acid synthase and apply it to probe protein-protein interactions with noncognate carrier proteins. Finally, we use solution-phase protein NMR spectroscopy to demonstrate that sulfonyl 3-alkynyl pantetheinamide is fully sequestered by the ACP, indicating that the crypto-ACP closely mimics the natural DH substrate. This cross-linking technology offers immediate potential to lock these biosynthetic enzymes in their native binding states by providing access to mechanistically cross-linked enzyme complexes, presenting a solution to ongoing structural challenges.
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Affiliation(s)
- Fumihiro Ishikawa
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, USA
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14
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Haushalter RW, Filipp FV, Ko KS, Yu R, Opella SJ, Burkart MD. Binding and "pKa" modulation of a polycyclic substrate analogue in a type II polyketide acyl carrier protein. ACS Chem Biol 2011; 6:413-8. [PMID: 21268653 DOI: 10.1021/cb200004k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Type II polyketide synthases are biosynthetic enzymatic pathways responsible for the production of complex aromatic natural products with important biological activities. In these systems, biosynthetic intermediates are covalently bound to a small acyl carrier protein that associates with the synthase enzymes and delivers the bound intermediate to each active site. In the closely related fatty acid synthases of bacteria and plants, the acyl carrier protein acts to sequester and protect attached intermediates within its helices. Here we investigate the type II polyketide synthase acyl carrier protein from the actinorhodin biosynthetic pathway and demonstrate its ability to internalize the tricyclic, polar molecule emodic acid. Elucidating the interaction of acyl carrier proteins with bound analogues resembling late-stage intermediates in the actinorhodin pathway could prove valuable in efforts to engineer these systems toward rational design and biosynthesis of novel compounds.
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Affiliation(s)
- Robert W. Haushalter
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0358, United States
| | - Fabian V. Filipp
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0358, United States
| | - Kwang-seuk Ko
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0358, United States
| | - Ricky Yu
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0358, United States
| | - Stanley J. Opella
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0358, United States
| | - Michael D. Burkart
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92037-0358, United States
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15
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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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16
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Beltran-Alvarez P, Arthur CJ, Cox RJ, Crosby J, Crump MP, Simpson TJ. Preliminary kinetic analysis of acyl carrier protein–ketoacylsynthase interactions in the actinorhodin minimal polyketide synthase. MOLECULAR BIOSYSTEMS 2009; 5:511-8. [DOI: 10.1039/b821844g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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17
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Evans SE, Williams C, Arthur CJ, Burston SG, Simpson TJ, Crosby J, Crump MP. An ACP Structural Switch: Conformational Differences between the Apo and Holo Forms of the Actinorhodin Polyketide Synthase Acyl Carrier Protein. Chembiochem 2008; 9:2424-32. [DOI: 10.1002/cbic.200800180] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Beltran-Alvarez P, Cox RJ, Crosby J, Simpson TJ. Dissecting the component reactions catalyzed by the actinorhodin minimal polyketide synthase. Biochemistry 2007; 46:14672-81. [PMID: 18034463 DOI: 10.1021/bi701784c] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The actinorhodin (act) minimal polyketide synthase (PKS) from Streptomyces coelicolor consists of three proteins: an acyl carrier protein (ACP) and two beta-ketoacyl ACP synthase components known as KSalpha and KSbeta. The act minimal PKS catalyzes at least 18 separate reactions which can be divided into loading, initiation, extension, and cyclization and release phases. Two quantitative kinetic assays were developed and used to measure individual rate and Michaelis constants for loading, initiation and extension steps. In the minimal PKS, the reaction between malonyl CoA and ACP to form malonyl ACP (loading) is the rate-limiting step (kcat = 0.49 min-1, KM = 207 microM). This reaction increases 5-fold in rate in the presence of KSalphaKSbeta (kcat = 2.3 min-1, KM = 215 microM). In the presence of S. coelicolor malonyl CoA:ACP transacylase (MCAT), the rate of loading increases and the kinetic parameters of malonyl-ACP as a substrate of KSalphaKSbeta can be measured (kcat = 20.6 min-1, KM = 2.4 microM). Under these conditions, it appears that decarboxylation of malonyl-ACP to form acetyl-ACP (initiation) is the rate-limiting step. When an excess of acetyl ACP is supplied, either chain extension, cyclization, or release steps become rate limiting (k approximately 60 min-1). No ACP-bound intermediates could be observed, suggesting that partially or fully extended chains do not accumulate because chain extension is rate limiting under these conditions and that cyclization and release are fast. apo-ACP acts as a mixed inhibitor of malonyl ACP binding to KSalpha/KSbeta (Kic = 50 microM, Kiu = 137 microM), but apo-ACP does not appear to inhibit MCAT.
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19
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Ma Y, Smith LH, Cox RJ, Beltran-Alvarez P, Arthur CJ, Simpson F R S TJ. Catalytic relationships between type I and type II iterative polyketide synthases: The Aspergillus parasiticus norsolorinic acid synthase. Chembiochem 2007; 7:1951-8. [PMID: 17086560 DOI: 10.1002/cbic.200600341] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Norsolorinic acid synthase (NSAS) is a type I iterative polyketide synthase that occurs in the filamentous fungus Aspergillus parasiticus. PCR was used to clone fragments of NSAS corresponding to the acyl carrier protein (ACP), acyl transferase (AT) and beta-ketoacyl-ACP synthase (KS) catalytic domains. Expression of these gene fragments in Escherichia coli led to the production of soluble ACP and AT proteins. Coexpression of ACP with E. coli holo-ACP synthase (ACPS) let to production of NSAS holo-ACP, which could also be formed in vitro by using Streptomyces coelicolor ACPS. Analysis by mass spectrometry showed that, as with other type I carrier proteins, self-malonylation is not observed in the presence of malonyl CoA alone. However, the NSAS holo-ACP serves as substrate for S. coelicolor MCAT, S. coelicolor actinorhodin holo-ACP and NSAS AT domain-catalysed malonate transfer from malonyl CoA. The AT domain could transfer malonate from malonyl CoA to NSAS holo-ACP, but not hexanoate or acetate from either the cognate CoA or FAS ACP species to NSAS holo-ACP. The NSAS holo-ACP was also active in actinorhodin minimal PKS assays, but only in the presence of exogenous malonyl transferases.
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Affiliation(s)
- Yue Ma
- School of Chemistry, University of Bristol, Cantock's Close, Clifton, Bristol, BS8 1TS, UK
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20
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Worthington AS, Rivera H, Torpey JW, Alexander MD, Burkart MD. Mechanism-based protein cross-linking probes to investigate carrier protein-mediated biosynthesis. ACS Chem Biol 2006; 1:687-91. [PMID: 17184132 DOI: 10.1021/cb6003965] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fatty acid, polyketide, and nonribosomal peptide biosynthetic enzymes perform structural modifications upon small molecules that remain tethered to a carrier protein. This manuscript details the design and analysis of cross-linking substrates that are selective for acyl carrier proteins and their cognate condensing enzymes. These inactivators are engineered through a covalent linkage to fatty acid acyl carrier protein via post-translational modification to contain a reactive probe that traps the active site cysteine residue of ketosynthase domains. These proteomic tools are applied to Escherichia coli fatty acid synthase enzymes, where KASI and KASII selectively cross-link ACP-bound epoxide and chloroacrylate moieties. These mechanism-based, protein-protein fusion reagents also demonstrated cross-linking of KASI to type II polyketide ACPs, while nonribosomal peptide carrier proteins showed no reactivity. Similar investigations into protein-protein interactions, proximity effects, and substrate specificities will be required to complete the mechanistic understanding of these pathways.
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21
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Arthur CJ, Szafranska AE, Long J, Mills J, Cox RJ, Findlow SC, Simpson TJ, Crump MP, Crosby J. The malonyl transferase activity of type II polyketide synthase acyl carrier proteins. ACTA ACUST UNITED AC 2006; 13:587-96. [PMID: 16793516 DOI: 10.1016/j.chembiol.2006.03.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 03/13/2006] [Accepted: 03/24/2006] [Indexed: 11/21/2022]
Abstract
Acyl carrier proteins (ACPs) play a fundamental role in directing intermediates among the enzyme active sites of fatty acid and polyketide synthases (PKSs). In this paper, we demonstrate that the Streptomyces coelicolor (S. coelicolor) actinorhodin (act) PKS ACP can catalyze transfer of malonate to type II S. coelicolor fatty acid synthase (FAS) and other PKS ACPs in vitro. The reciprocal transfer from S. coelicolor FAS ACP to a PKS ACP was not observed. Several mutations in both act ACP and S. coelicolor FAS ACP could be classified by their participation in either donation or acceptance of this malonyl group. These mutations indicated that self-malonylation and malonyl transfer could be completely decoupled, implying that they were separate processes and that a FAS ACP could be converted from a non-malonyl-transferring protein to one with malonyl transferase activity.
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Affiliation(s)
- Christopher J Arthur
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, United Kingdom
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22
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Findlow SC, Winsor C, Simpson TJ, Crosby J, Crump MP. Solution structure and dynamics of oxytetracycline polyketide synthase acyl carrier protein from Streptomyces rimosus. Biochemistry 2003; 42:8423-33. [PMID: 12859187 DOI: 10.1021/bi0342259] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Type II polyketide synthases (PKSs) utilize a dedicated and essential acyl carrier protein (ACP) in the biosynthesis of a specific polyketide product. As part of our ongoing studies into the mechanisms and control of polyketide biosynthesis, we report the second structure of a polyketide synthase ACP. In this work, multidimensional, heteronuclear NMR was employed to investigate the structure and dynamics of the ACP involved in the biosynthesis of the commonly prescribed polyketide antibiotic, oxytetracycline (otc). An ensemble of 28 structures of the 95 amino acid otc ACP (9916Da) was computed by simulated annealing with the inclusion of 1132 experimental restraints. Atomic RMSDs about the mean structure for all 28 models is 0.66 A for backbone atoms, 1.15 A for all heavy atoms (both values calculated for the folded part of the protein (residues 3-80)), and 0.41 A for backbone atoms within secondary structure. Otc ACP adopts the typical right-handed, four-helix fold of currently known ACPs but with the addition of a 13-residue flexible C-terminus. A comparison of the global folds of all structurally characterized ACPs is described, illustrating that PKS ACPs show clear differences as well as similarities to FAS ACPs. (15)N relaxation experiments for the protein backbone also reveal that the long loop between helices I and II is flexible and helix II, a proposed site of protein-protein interactions, shows conformational exchange. The helices of the ACP form a rigid scaffold for the protein, but these are interspersed with an unusual proportion of flexible linker regions.
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Affiliation(s)
- Stuart C Findlow
- School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton, SO16 7PX, United Kingdom
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23
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Szafranska AE, Hitchman TS, Cox RJ, Crosby J, Simpson TJ. Kinetic and mechanistic analysis of the malonyl CoA:ACP transacylase from Streptomyces coelicolor indicates a single catalytically competent serine nucleophile at the active site. Biochemistry 2002; 41:1421-7. [PMID: 11814333 DOI: 10.1021/bi012001p] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The source of malonyl groups for polyketide and fatty acid biosynthesis is malonyl CoA. During fatty acid and polyketide biosynthesis, malonyl groups are normally transferred to the acyl carrier protein (ACP) component of the synthase by a malonyl CoA:holo-ACP transacylase (MCAT) enzyme. The fatty acid synthase (FAS) malonyl CoA:ACP transacylase from Streptomyces coelicolor was expressed in Escherichia coli as a hexahistidine-tagged (His(6)) fusion protein in high yield. The His(6)-MCAT was purified to homogeneity using standard techniques, and kinetic analysis of the malonylation of S. coelicolorFAS holo-ACP, catalyzed by His(6)-MCAT, gave K(infinity) (M) values of 73 (ACP) and 60 microM (malonyl CoA). A catalytic constant k (infinity) (M) of 450 s(-1) and specificity constants k (infinity) (M)/K (infinity) (M) of 6.2 (ACP) and 7.5 microM(-1) s(-1) (malonyl CoA) were measured. Malonyl transfer to the E. coli FAS holo-ACP, catalyzed by His(6)-MCAT, was less efficient (k (infinity) (M)/K (infinity) (M) was 10% of that of the S. coelicolor ACP). Incubation of MCAT with the serine specific agent PMSF caused inhibition of malonyl transfer to FAS ACPs, and an S97A MCAT mutant was incapable of catalyzing malonyl transfer. Our results show that in the reaction with FAS holo-ACPs the S. coelicolor MCAT is very similar to the E. coli MCAT paradigm in terms of its kinetic mechanism and active site residues. These results indicate that no other active site nucleophile is involved in catalysis as has been suggested to explain recently reported observations.
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Affiliation(s)
- Anna E Szafranska
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
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Zhou P, Florova G, Reynolds KA. Polyketide synthase acyl carrier protein (ACP) as a substrate and a catalyst for malonyl ACP biosynthesis. CHEMISTRY & BIOLOGY 1999; 6:577-84. [PMID: 10421763 DOI: 10.1016/s1074-5521(99)80090-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND Using an acyl-acyl carrier protein (ACP) as a starter unit, type II polyketide synthases (PKSs) generate a wide range of polyketide products by successive decarboxylative condensations with the two-carbon donor malonyl (ACP). In vitro experiments have demonstrated that polyketide biosynthesis in reconstituted PKS systems requires the fatty acid synthase (FAS) enzyme malonyl CoA:ACP acyltransferase (FabD) from streptomycetes. It has also been shown that holo-ACPs from a type II PKS can catalyze self-malonylation in the presence of malonyl CoA and negate this FabD requirement. The relative roles of FabD and ACP self-malonylation in PKS biosynthesis in vivo are still not known. RESULTS We have examined the ACP specificity of the Streptomyces glaucescens FabD and shown that it reacts specifically with monomeric forms of ACP, with comparable k(cat)/K(M) values for ACPs from both type II PKS and FAS systems. Incubations of tetracenomycin ACP (TcmM) with the Escherichia coli FAS ACP (AcpP) unexpectedly revealed that, in addition to the self-malonylation process, TcmM can catalyze the malonylation of AcpP. The k(cat)/K(M) value for the TcmM-catalyzed malonylation of S. glaucescens FAS ACP is two orders of magnitude smaller than that observed for the FabD-catalyzed process. CONCLUSIONS The ability of a PKS ACP to catalyze malonylation of a FAS ACP is a surprising finding and demonstrates for the first time that PKS ACPs and FabD can catalyze the same reaction. The differences in the catalytic efficiency of these two proteins rationalizes in vitro observations that FabD-independent polyketide biosynthesis proceeds only at high concentrations of a PKS ACP.
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Affiliation(s)
- P Zhou
- ISBDD, Suite 212B, Virginia Commonwealth University, 800 East Leigh Street, Richmond, VA 23219, USA
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25
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Matharu AL, Cox RJ, Crosby J, Byrom KJ, Simpson TJ. MCAT is not required for in vitro polyketide synthesis in a minimal actinorhodin polyketide synthase from Streptomyces coelicolor. CHEMISTRY & BIOLOGY 1998; 5:699-711. [PMID: 9862793 DOI: 10.1016/s1074-5521(98)90663-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND It has been proposed that Streptomyces malonyl CoA: holo acyl carrier protein transacylases (MCATs) provide a link between fatty acid and polyketide biosynthesis. Two recent studies have provided evidence that the presence of MCAT is essential for polyketide synthesis to proceed in reconstituted minimal polyketide synthases (PKSs). In contrast to this, we previously showed that the holo acyl carrier proteins (ACPs) from type II PKSs are capable of catalytic self-malonylation in the presence of malonyl CoA, which suggests that MCAT might not be necessary for polyketide biosynthesis. RESULTS We reconstituted a homologous actinorhodin (act) type II minimal PKS in vitro. When act holo-ACP is present in limiting concentrations, MCAT is required by the synthase complex in order for polyketide biosynthesis to proceed. When holo-ACP is present in excess, however, efficient polyketide synthesis proceeds without MCAT. The rate of polyketide production increases with holo-ACP concentration, but at low ACP concentration or equimolar AC:KS:CLF (KS, ketosynthase; CLF, chain length determining factor) concentrations this rate is significantly lower than expected, indicating that free holo-ACP is sequestered by the KS/CLF complex. CONCLUSIONS The rate of polyketide biosynthesis is dictated by the ratio of holo-ACP to KS and CLF, as well as by the total protein concentration. There is no absolute requirement for MCAT in polyketide biosynthesis in vitro, although the role of MCAT during polyketide synthesis in vivo remains an open question. MCAT might be responsible for the rate enhancement of malonyl transfer at very low free holo-ACP concentrations or it could be required to catalyse the transfer of malonyl groups from malonyl CoA to sequestered holo-ACP.
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Affiliation(s)
- A L Matharu
- School of Chemistry University of Bristol Cantock's Close Bristol BS8 1TS UK
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