1
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D'Ambrosio HK, Keeler AM, Derbyshire ER. Examination of Secondary Metabolite Biosynthesis in Apicomplexa. Chembiochem 2023; 24:e202300263. [PMID: 37171468 DOI: 10.1002/cbic.202300263] [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: 04/01/2023] [Revised: 05/11/2023] [Accepted: 05/12/2023] [Indexed: 05/13/2023]
Abstract
Natural product discovery has traditionally relied on the isolation of small molecules from producing species, but genome-sequencing technology and advances in molecular biology techniques have expanded efforts to a wider array of organisms. Protists represent an underexplored kingdom for specialized metabolite searches despite bioinformatic analysis that suggests they harbor distinct biologically active small molecules. Specifically, pathogenic apicomplexan parasites, responsible for billions of global infections, have been found to possess multiple biosynthetic gene clusters, which hints at their capacity to produce polyketide metabolites. Biochemical studies have revealed unique features of apicomplexan polyketide synthases, but to date, the identity and function of the polyketides synthesized by these megaenzymes remains unknown. Herein, we discuss the potential for specialized metabolite production in protists and the possible evolution of polyketide biosynthetic gene clusters in apicomplexan parasites. We then focus on a polyketide synthase from the apicomplexan Toxoplasma gondii to discuss the unique domain architecture and properties of these proteins when compared to previously characterized systems, and further speculate on the possible functions for polyketides in these pathogenic parasites.
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Affiliation(s)
- Hannah K D'Ambrosio
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA
| | - Aaron M Keeler
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA
| | - Emily R Derbyshire
- Department of Chemistry, Duke University, 124 Science Drive, Durham, NC 27708, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, 213 Research Drive, Durham, NC 27710, USA
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2
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Guzman KM, Cogan DP, Brodsky KL, Soohoo AM, Li X, Sevillano N, Mathews II, Nguyen KP, Craik CS, Khosla C. Discovery and Characterization of Antibody Probes of Module 2 of the 6-Deoxyerythronolide B Synthase. Biochemistry 2023. [PMID: 37184546 DOI: 10.1021/acs.biochem.3c00156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Fragment antigen-binding domains of antibodies (Fabs) are powerful probes of structure-function relationships of assembly line polyketide synthases (PKSs). We report the discovery and characterization of Fabs interrogating the structure and function of the ketosynthase-acyltransferase (KS-AT) core of Module 2 of the 6-deoxyerythronolide B synthase (DEBS). Two Fabs (AC2 and BB1) were identified to potently inhibit the catalytic activity of Module 2. Both AC2 and BB1 were found to modulate ACP-mediated reactions catalyzed by this module, albeit by distinct mechanisms. AC2 primarily affects the rate (kcat), whereas BB1 increases the KM of an ACP-mediated reaction. A third Fab, AA5, binds to the KS-AT fragment of DEBS Module 2 without altering either parameter; it is phenotypically reminiscent of a previously characterized Fab, 1B2, shown to principally recognize the N-terminal helical docking domain of DEBS Module 3. Crystal structures of AA5 and 1B2 bound to the KS-AT fragment of Module 2 were solved to 2.70 and 2.65 Å resolution, respectively, and revealed entirely distinct recognition features of the two antibodies. The new tools and insights reported here pave the way toward advancing our understanding of the structure-function relationships of DEBS Module 2, arguably the most well-studied module of an assembly line PKS.
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Affiliation(s)
- Katarina M Guzman
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Dillon P Cogan
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Krystal L Brodsky
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Alexander M Soohoo
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
| | - Xiuyuan Li
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Natalia Sevillano
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158, United States
| | - Irimpan I Mathews
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, California 94025, United States
| | - Khanh P Nguyen
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Charles S Craik
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94158, United States
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, Stanford, California 94305, United States
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Sarafan ChEM-H, Stanford University, Stanford, California 94305, United States
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3
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Kudo F, Kishikawa K, Tsuboi K, Kido T, Usui T, Hashimoto J, Shin-Ya K, Miyanaga A, Eguchi T. Acyltransferase Domain Exchange between Two Independent Type I Polyketide Synthases in the Same Producer Strain of Macrolide Antibiotics. Chembiochem 2023; 24:e202200670. [PMID: 36602093 DOI: 10.1002/cbic.202200670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/06/2023]
Abstract
Streptomyces graminofaciens A-8890 produces two macrolide antibiotics, FD-891 and virustomycin A, both of which show significant biological activity. In this study, we identified the virustomycin A biosynthetic gene cluster, which encodes type I polyketide synthases (PKSs), ethylmalonyl-CoA biosynthetic enzymes, methoxymalony-acyl carrier protein biosynthetic enzymes, and post-PKS modification enzymes. Next, we demonstrated that the acyltransferase domain can be exchanged between the Vsm PKSs and the PKSs involved in FD-891 biosynthesis (Gfs PKSs), without any supply problems of the unique extender units. We exchanged the malonyltransferase domain in the loading module of Gfs PKS with the ethylmalonyltransferase domain and the methoxymalonyltransferase domain of Vsm PKSs. Consequently, the expected two-carbon-elongated analog 26-ethyl-FD-891 was successfully produced with a titer comparable to FD-891 production by the wild type; however, exchange with the methoxymalonyltransferase domain did not produce any FD-891 analogs. Furthermore, 26-ethyl-FD-891 showed potent cytotoxic activity against HeLa cells, like natural FD-891.
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Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Meguro-ku, O-okayama, Tokyo, 152-8551, Japan
| | - Kosuke Kishikawa
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Meguro-ku, O-okayama, Tokyo, 152-8551, Japan
| | - Kazuma Tsuboi
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Meguro-ku, O-okayama, Tokyo, 152-8551, Japan
| | - Takafusa Kido
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Meguro-ku, O-okayama, Tokyo, 152-8551, Japan
| | - Takeo Usui
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, 305-8572, Ibaraki, Japan
| | - Junko Hashimoto
- Japan Biological Informatics Consortium (JBIC), 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Kazuo Shin-Ya
- National Institute of Advanced Industrial Science and Technology, 2-4-7 Aomi, Koto-ku, Tokyo, 135-0064, Japan
| | - Akimasa Miyanaga
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Meguro-ku, O-okayama, Tokyo, 152-8551, Japan
| | - Tadashi Eguchi
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Meguro-ku, O-okayama, Tokyo, 152-8551, Japan
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4
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Miyanaga A, Kawada K, Chisuga T, Kudo F, Eguchi T. Structural Basis of Transient Interactions of Acyltransferase VinK with the Loading Acyl Carrier Protein of the Vicenistatin Modular Polyketide Synthase. Biochemistry 2023; 62:17-21. [PMID: 36512613 DOI: 10.1021/acs.biochem.2c00645] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Acyltransferase (AT) recognizes its cognate acyl carrier protein (ACP) for functional transfer of an acyl unit in polyketide biosynthesis. However, structural characterization of AT-ACP complexes is limited because of the weak and transient interactions between them. In the biosynthesis of macrolactam polyketide vicenistatin, the trans-acting loading AT VinK transfers a dipeptidyl unit from the stand-alone ACP VinL to the ACP domain (VinP1ACPL) of the loading module of modular polyketide synthase VinP1. Although the previously determined structure of the VinK-VinL complex clearly illustrates the VinL recognition mechanism of VinK, how VinK recognizes VinP1ACPL remains unclear. Here, the crystal structure of a covalent VinK-VinP1ACPL complex formed with a pantetheine-type cross-linking probe is reported at 3.0 Å resolution. The structure of the VinK-VinP1ACPL complex provides detailed insights into the transient interactions between VinK and VinP1ACPL. The importance of residues in the binding interface was confirmed by site-directed mutational analyses. The binding interface between VinK and VinP1ACPL is similar to that between VinK and VinL, although some of the interface residues are different. However, the ACP orientation and interaction mode observed in the VinK-VinP1ACPL complex are different from those observed in other AT-ACP complexes such as the disorazole trans-AT-ACP complex and cis-AT-ACP complexes of modular polyketide synthases. Thus, AT-ACP binding interface interactions are different in each type of AT-ACP pair.
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Affiliation(s)
- Akimasa Miyanaga
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Koichi Kawada
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Taichi Chisuga
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Tadashi Eguchi
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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5
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Welch SD, Cossin J, Paulsel TQ, Williams GJ. Targeted Enzyme Modifications Enable Regioselective Biosynthesis of Fluorinated Polyketides. CHEM CATALYSIS 2022; 2:2440-2443. [PMID: 38213411 PMCID: PMC10783197 DOI: 10.1016/j.checat.2022.09.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
In attempts to enhance natural products as therapeutic agents, fluorination has emerged as a new tool for synthetic biologists and chemists. In recent articles published in Nature Chem. and Nature Chem. Bio., Grininger, Chang, and co-workers leveraged their expertise in engineering polyketide biosynthesis to incorporate fluorine into polyketide scaffolds.
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Affiliation(s)
- Sydney D. Welch
- Department of Chemistry, North Carolina State University, Raleigh, NC, United States
| | - Jared Cossin
- Department of Chemistry, North Carolina State University, Raleigh, NC, United States
| | - Thaddeus Q. Paulsel
- Department of Chemistry, North Carolina State University, Raleigh, NC, United States
| | - Gavin J. Williams
- Department of Chemistry, North Carolina State University, Raleigh, NC, United States
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, United States
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6
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Zhang H, Zhang S, Zhang J, Qi H, Wang H, Zhang L, Huang J, Wang J. Acyltransferase Domain Swapping for the Production of Tenvermectin B Metabolites in Genetically Engineered Strain Streptomyces avermitilis HU02. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11994-12003. [PMID: 36121904 DOI: 10.1021/acs.jafc.2c04482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Tenvermectins A and B (TVMs A and B) are hybrid natural compounds of avermectins and milbemycins with enhanced insecticidal activity. Aiming at obtaining a strain for the production of the higher activity metabolite-TVM-B as a major constituent, a recombinant strain Streptomyces avermitilis HU02 was constructed by a domain swapping strategy in which milA1-AT0 gene in S. avermitilis MHJ1011 was replaced by eryA1-AT0 gene from Saccharopolyspora erythraea ATCC 40137. Chemical investigation on the culture of S. avermitilis HU02 led to the isolation of a large amount of TVM-B and trace amounts of five new TVM-B analogues. The structures of new metabolites were elucidated by extensive spectroscopic analysis including 1D and 2D nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry data. The bioassay test indicated that five new TVM-B analogues exhibited potent insecticidal activity against Tetranychus cinnabarinus and Bursaphelenchus xylophilus. This study provided a feasible route to the low-cost production of TVM-B and enriched the structural diversity of TVM-B metabolites.
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Affiliation(s)
- Hui Zhang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Science, Huzhou University, Huzhou 313000, China
- Institute of Natural Active Substances Research and Utilization, School of Agriculture and Bioengineering, Taizhou Vocational College of Science and Technology, Taizhou 318020, China
- Life Science and Biotechnology Research Center, School of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Shaoyong Zhang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Science, Huzhou University, Huzhou 313000, China
| | - Ji Zhang
- Life Science and Biotechnology Research Center, School of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Huan Qi
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Science, Huzhou University, Huzhou 313000, China
| | - Han Wang
- Life Science and Biotechnology Research Center, School of Life Science, Northeast Agricultural University, Harbin 150030, China
| | - Liqin Zhang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Science, Huzhou University, Huzhou 313000, China
| | - Jun Huang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Science, Huzhou University, Huzhou 313000, China
- Zhejiang Makohs Biotech Co., Ltd, Taizhou 318000, P.R. China
| | - Jidong Wang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Science, Huzhou University, Huzhou 313000, China
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7
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Sirirungruang S, Ad O, Privalsky TM, Ramesh S, Sax JL, Dong H, Baidoo EEK, Amer B, Khosla C, Chang MCY. Engineering site-selective incorporation of fluorine into polyketides. Nat Chem Biol 2022; 18:886-893. [PMID: 35817967 PMCID: PMC10030150 DOI: 10.1038/s41589-022-01070-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 05/23/2022] [Indexed: 02/01/2023]
Abstract
Although natural products and synthetic small molecules both serve important medicinal functions, their structures and chemical properties are relatively distinct. To expand the molecular diversity available for drug discovery, one strategy is to blend the effective attributes of synthetic and natural molecules. A key feature found in synthetic compounds that is rare in nature is the use of fluorine to tune drug behavior. We now report a method to site-selectively incorporate fluorine into complex structures to produce regioselectively fluorinated full-length polyketides. We engineered a fluorine-selective trans-acyltransferase to produce site-selectively fluorinated erythromycin precursors in vitro. We further demonstrated that these analogs could be produced in vivo in Escherichia coli on engineering of the fluorinated extender unit pool. By using engineered microbes, elaborate fluorinated compounds can be produced by fermentation, offering the potential for expanding the identification and development of bioactive fluorinated small molecules.
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Affiliation(s)
| | - Omer Ad
- Department of Chemistry, University of California, Berkeley, CA, USA
| | | | - Swetha Ramesh
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Joel L Sax
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Hongjun Dong
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - Edward E K Baidoo
- Joint Bioenergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, USA
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Energy, Agile BioFoundry, Emeryville, CA, USA
| | - Bashar Amer
- Joint Bioenergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA, USA
- Biological Systems and Engineering, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA, USA
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
| | - Michelle C Y Chang
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
- Department of Chemistry, University of California, Berkeley, CA, USA.
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, USA.
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8
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Feng Y, Zhang F, Huang S, Deng Z, Bai L, Zheng J. Structural visualization of transient interactions between the cis-acting acyltransferase and acyl carrier protein of the salinomycin modular polyketide synthase. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:779-791. [DOI: 10.1107/s2059798322004612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 05/02/2022] [Indexed: 11/10/2022]
Abstract
Transient protein–protein interactions between cis-acting acyltransferase (AT) and acyl carrier protein (ACP) domains are critical for the catalysis and processivity of modular polyketide synthases (mPKSs), but are challenging for structural characterization due to the intrinsically weak binding affinity. Here, a stable complex of cis-acting AT and ACP domains from the ninth module of the salinomycin mPKS was obtained using a maleimide cross-linker and the structure of the complex was determined at 2.6 Å resolution. The crystal structure shows that the AT in combination with the ketosynthase (KS)-to-AT linker forms a C-shaped architecture to embrace the ACP. The large hydrolase subdomain of the AT serves as a major binding platform for the ACP, while the small ferredoxin-like subdomain of the AT and the KS-to-AT linker cooperate with each other to constrain binding of the ACP. The importance of interface residues in cis-acting AT–ACP interactions was confirmed by mutagenesis assays. The interaction mode observed in the cis-acting AT–ACP complex is completely different from those observed in trans-acting AT–ACP complexes, where the ACP primarily contacts the small domain of the AT. The complex structure provides detailed mechanistic insights into AT–ACP recognition in cis-AT mPKSs.
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9
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Klaus M, Rossini E, Linden A, Paithankar KS, Zeug M, Ignatova Z, Urlaub H, Khosla C, Köfinger J, Hummer G, Grininger M. Solution Structure and Conformational Flexibility of a Polyketide Synthase Module. JACS AU 2021; 1:2162-2171. [PMID: 34977887 PMCID: PMC8717363 DOI: 10.1021/jacsau.1c00043] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Indexed: 05/28/2023]
Abstract
Polyketide synthases (PKSs) are versatile C-C bond-forming enzymes that are broadly distributed in bacteria and fungi. The polyketide compound family includes many clinically useful drugs such as the antibiotic erythromycin, the antineoplastic epothilone, and the cholesterol-lowering lovastatin. Harnessing PKSs for custom compound synthesis remains an open challenge, largely because of the lack of knowledge about key structural properties. Particularly, the domains-well characterized on their own-are poorly understood in their arrangement, conformational dynamics, and interplay in the intricate quaternary structure of modular PKSs. Here, we characterize module 2 from the 6-deoxyerythronolide B synthase by small-angle X-ray scattering and cross-linking mass spectrometry with coarse-grained structural modeling. The results of this hybrid approach shed light on the solution structure of a cis-AT type PKS module as well as its inherent conformational dynamics. Supported by a directed evolution approach, we also find that acyl carrier protein (ACP)-mediated substrate shuttling appears to be steered by a nonspecific electrostatic interaction network.
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Affiliation(s)
- Maja Klaus
- Institute
of Organic Chemistry and Chemical Biology, Buchmann Institute for
Molecular Life Sciences, Goethe University
Frankfurt, Max-von-Laue Strasse 15, Frankfurt am Main 60438, Germany
| | - Emanuele Rossini
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, Max-von-Laue
Strasse 3, Frankfurt am Main 60438, Germany
| | - Andreas Linden
- Max
Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen 37077, Germany
- Institute
for Clinical Chemistry, University Medical
Center Göttingen, Robert Koch Strasse 40, Goettingen 37075, Germany
| | - Karthik S. Paithankar
- Institute
of Organic Chemistry and Chemical Biology, Buchmann Institute for
Molecular Life Sciences, Goethe University
Frankfurt, Max-von-Laue Strasse 15, Frankfurt am Main 60438, Germany
| | - Matthias Zeug
- Institute
of Organic Chemistry and Chemical Biology, Buchmann Institute for
Molecular Life Sciences, Goethe University
Frankfurt, Max-von-Laue Strasse 15, Frankfurt am Main 60438, Germany
| | - Zoya Ignatova
- Institute
for Biochemistry and Molecular Biology, University of Hamburg, Notkestrasse 85, Hamburg 22607, Germany
| | - Henning Urlaub
- Max
Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen 37077, Germany
- Institute
for Clinical Chemistry, University Medical
Center Göttingen, Robert Koch Strasse 40, Goettingen 37075, Germany
| | - Chaitan Khosla
- Department
of Chemistry, Stanford ChEM-H, Department of Chemical Engineering Stanford University, Stanford, California 94305, United States
| | - Jürgen Köfinger
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, Max-von-Laue
Strasse 3, Frankfurt am Main 60438, Germany
| | - Gerhard Hummer
- Department
of Theoretical Biophysics, Max Planck Institute
of Biophysics, Max-von-Laue
Strasse 3, Frankfurt am Main 60438, Germany
- Institute
of Biophysics, Goethe University Frankfurt, Max-von-Laue Strasse 1, Frankfurt am Main 60438, Germany
| | - Martin Grininger
- Institute
of Organic Chemistry and Chemical Biology, Buchmann Institute for
Molecular Life Sciences, Goethe University
Frankfurt, Max-von-Laue Strasse 15, Frankfurt am Main 60438, Germany
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10
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Miyanaga A, Ouchi R, Kudo F, Eguchi T. Complex structure of the acyltransferase VinK and the carrier protein VinL with a pantetheine cross-linking probe. Acta Crystallogr F Struct Biol Commun 2021; 77:294-302. [DOI: 10.1107/s2053230x21008761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/22/2021] [Indexed: 01/16/2023] Open
Abstract
Acyltransferases are responsible for the selection and loading of acyl units onto carrier proteins in polyketide and fatty-acid biosynthesis. Despite the importance of protein–protein interactions between the acyltransferase and the carrier protein, structural information on acyltransferase–carrier protein interactions is limited because of the transient interactions between them. In the biosynthesis of the polyketide vicenistatin, the acyltransferase VinK recognizes the carrier protein VinL for the transfer of a dipeptidyl unit. The crystal structure of a VinK–VinL covalent complex formed with a 1,2-bismaleimidoethane cross-linking reagent has been determined previously. Here, the crystal structure of a VinK–VinL covalent complex formed with a pantetheine cross-linking probe is reported at 1.95 Å resolution. In the structure of the VinK–VinL–probe complex, the pantetheine probe that is attached to VinL is covalently connected to the side chain of the mutated Cys106 of VinK. The interaction interface between VinK and VinL is essentially the same in the two VinK–VinL complex structures, although the position of the pantetheine linker slightly differs. This structural observation suggests that interface interactions are not affected by the cross-linking strategy used.
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11
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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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12
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Grabowska AD, Brison Y, Maveyraud L, Gavalda S, Faille A, Nahoum V, Bon C, Guilhot C, Pedelacq JD, Chalut C, Mourey L. Molecular Basis for Extender Unit Specificity of Mycobacterial Polyketide Synthases. ACS Chem Biol 2020; 15:3206-3216. [PMID: 33237724 DOI: 10.1021/acschembio.0c00772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mycobacterium tuberculosis is the causative agent of the tuberculosis disease, which claims more human lives each year than any other bacterial pathogen. M. tuberculosis and other mycobacterial pathogens have developed a range of unique features that enhance their virulence and promote their survival in the human host. Among these features lies the particular cell envelope with high lipid content, which plays a substantial role in mycobacterial pathogenicity. Several envelope components of M. tuberculosis and other mycobacteria, e.g., mycolic acids, phthiocerol dimycocerosates, and phenolic glycolipids, belong to the "family" of polyketides, secondary metabolites synthesized by fascinating versatile enzymes-polyketide synthases. These megasynthases consist of multiple catalytic domains, among which the acyltransferase domain plays a key role in selecting and transferring the substrates required for polyketide extension. Here, we present three new crystal structures of acyltransferase domains of mycobacterial polyketide synthases and, for one of them, provide evidence for the identification of residues determining extender unit specificity. Unravelling the molecular basis for such specificity is of high importance considering the role played by extender units for the final structure of key mycobacterial components. This work provides major advances for the use of mycobacterial polyketide synthases as potential therapeutic targets and, more generally, contributes to the prediction and bioengineering of polyketide synthases with desired specificity.
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Affiliation(s)
- Anna D. Grabowska
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Yoann Brison
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Laurent Maveyraud
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Sabine Gavalda
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Alexandre Faille
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Virginie Nahoum
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Cécile Bon
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Christophe Guilhot
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Jean-Denis Pedelacq
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Christian Chalut
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
| | - Lionel Mourey
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, 31077 Toulouse, France
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13
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Drufva EE, Hix EG, Bailey CB. Site directed mutagenesis as a precision tool to enable synthetic biology with engineered modular polyketide synthases. Synth Syst Biotechnol 2020; 5:62-80. [PMID: 32637664 PMCID: PMC7327777 DOI: 10.1016/j.synbio.2020.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/01/2020] [Accepted: 04/06/2020] [Indexed: 12/04/2022] Open
Abstract
Modular polyketide synthases (PKSs) are a multidomain megasynthase class of biosynthetic enzymes that have great promise for the development of new compounds, from new pharmaceuticals to high value commodity and specialty chemicals. Their colinear biosynthetic logic has been viewed as a promising platform for synthetic biology for decades. Due to this colinearity, domain swapping has long been used as a strategy to introduce molecular diversity. However, domain swapping often fails because it perturbs critical protein-protein interactions within the PKS. With our increased level of structural elucidation of PKSs, using judicious targeted mutations of individual residues is a more precise way to introduce molecular diversity with less potential for global disruption of the protein architecture. Here we review examples of targeted point mutagenesis to one or a few residues harbored within the PKS that alter domain specificity or selectivity, affect protein stability and interdomain communication, and promote more complex catalytic reactivity.
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Key Words
- ACP, acyl carrier protein
- AT, acyltransferase
- DEBS, 6-deoxyerthronolide B synthase
- DH, dehydratase
- EI, enoylisomerase
- ER, enoylreductase
- KR, ketoreductase
- KS, ketosynthase
- LM, loading module
- MT, methyltransferase
- Mod, module
- PKS, polyketide synthase
- PS, pyran synthase
- Polyketide synthase
- Protein engineering
- Rational design
- SNAC, N-acetyl cysteamine
- Saturation mutagenesis
- Site directed mutagenesis
- Synthetic biology
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Affiliation(s)
- Erin E. Drufva
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, 37996, USA
| | - Elijah G. Hix
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, 37996, USA
| | - Constance B. Bailey
- Department of Chemistry, University of Tennessee-Knoxville, Knoxville, TN, 37996, USA
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14
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Moretto L, Heylen R, Holroyd N, Vance S, Broadhurst RW. Modular type I polyketide synthase acyl carrier protein domains share a common N-terminally extended fold. Sci Rep 2019; 9:2325. [PMID: 30787330 PMCID: PMC6382882 DOI: 10.1038/s41598-019-38747-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/15/2018] [Indexed: 11/09/2022] Open
Abstract
Acyl carrier protein (ACP) domains act as interaction hubs within modular polyketide synthase (PKS) systems, employing specific protein-protein interactions to present acyl substrates to a series of enzyme active sites. Many domains from the multimodular PKS that generates the toxin mycolactone display an unusually high degree of sequence similarity, implying that the few sites which vary may do so for functional reasons. When domain boundaries based on prior studies were used to prepare two isolated ACP segments from this system for studies of their interaction properties, one fragment adopted the expected tertiary structure, but the other failed to fold, despite sharing a sequence identity of 49%. Secondary structure prediction uncovered a previously undetected helical region (H0) that precedes the canonical helix-bundle ACP topology in both cases. This article reports the NMR solution structures of two N-terminally extended mycolactone mACP constructs, mH0ACPa and mH0ACPb, both of which possess an additional α-helix that behaves like a rigid component of the domain. The interactions of these species with a phosphopantetheinyl transferase and a ketoreductase domain are unaffected by the presence of H0, but a shorter construct that lacks the H0 region is shown to be substantially less thermostable than mH0ACPb. Bioinformatics analysis suggests that the extended H0-ACP motif is present in 98% of type I cis-acyltransferase PKS chain-extension modules. The polypeptide linker that connects an H0-ACP motif to the preceding domain must therefore be ~12 residues shorter than previously thought, imposing strict limits on ACP-mediated substrate delivery within and between PKS modules.
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Affiliation(s)
- Luisa Moretto
- Department of Chemistry and Biomedical Sciences, Linnaeus University, Smålandsgatan-24, 392 34, Kalmar, Sweden
| | - Rachel Heylen
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK
| | - Natalie Holroyd
- Department of Medical Physics and Bioengineering, University College London, London, WC1E 6BT, UK
| | - Steven Vance
- Crescendo Biologics Ltd, Meditrina Building 260, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - R William Broadhurst
- Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge, CB2 1GA, UK.
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15
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Meinke JL, Mehaffey MR, Wagner DT, Sun N, Zhang Z, Brodbelt JS, Keatinge-Clay AT. Structural and Functional Studies of a gem-Dimethylating Methyltransferase from a trans-Acyltransferase Assembly Line. ACS Chem Biol 2018; 13:3306-3314. [PMID: 30371052 DOI: 10.1021/acschembio.8b00733] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The methyl substituents in products of trans-acyltransferase assembly lines are usually incorporated by S-adenosyl-methionine (SAM)-dependent methyltransferase (MT) domains. The gem-dimethyl moieties within the polyketide disorazol are installed through the iterative action of an MT in the third module of its assembly line. The 1.75-Å-resolution crystal structure of this MT helps elucidate how it catalyzes the addition of two methyl groups. Activity assays of point mutants on β-ketoacyl chains linked to an acyl carrier protein and N-acetylcysteamine provide additional insights into the roles of active site residues. The replacement of an alanine with a phenylalanine at an apparent gatekeeping position resulted in more monomethylation than dimethylation. MTs may form an interface with ketoreductases (KRs) and even mediate the docking of trans-acyltransferase assembly line polypeptides through this association.
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Affiliation(s)
- Jessica L. Meinke
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - M. Rachel Mehaffey
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Drew T. Wagner
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Ningze Sun
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Zhicheng Zhang
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Jennifer S. Brodbelt
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Adrian T. Keatinge-Clay
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, United States
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16
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Dodge GJ, Maloney FP, Smith JL. Protein-protein interactions in "cis-AT" polyketide synthases. Nat Prod Rep 2018; 35:1082-1096. [PMID: 30188553 PMCID: PMC6207950 DOI: 10.1039/c8np00058a] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to the end of 2018 Polyketides are a valuable source of bioactive and clinically important molecules. The biosynthesis of these chemically complex molecules has led to the discovery of equally complex polyketide synthase (PKS) pathways. Crystallography has yielded snapshots of individual catalytic domains, di-domains, and multi-domains from a variety of PKS megasynthases, and cryo-EM studies have provided initial views of a PKS module in a series of defined biochemical states. Here, we review the structural and biochemical results that shed light on the protein-protein interactions critical to catalysis by PKS systems with an embedded acyltransferase. Interactions include those that occur both within and between PKS modules, as well as with accessory enzymes.
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Affiliation(s)
- Greg J Dodge
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA 48109.
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17
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Musiol-Kroll EM, Wohlleben W. Acyltransferases as Tools for Polyketide Synthase Engineering. Antibiotics (Basel) 2018; 7:antibiotics7030062. [PMID: 30022008 PMCID: PMC6164871 DOI: 10.3390/antibiotics7030062] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 07/14/2018] [Accepted: 07/16/2018] [Indexed: 12/16/2022] Open
Abstract
Polyketides belong to the most valuable natural products, including diverse bioactive compounds, such as antibiotics, anticancer drugs, antifungal agents, immunosuppressants and others. Their structures are assembled by polyketide synthases (PKSs). Modular PKSs are composed of modules, which involve sets of domains catalysing the stepwise polyketide biosynthesis. The acyltransferase (AT) domains and their “partners”, the acyl carrier proteins (ACPs), thereby play an essential role. The AT loads the building blocks onto the “substrate acceptor”, the ACP. Thus, the AT dictates which building blocks are incorporated into the polyketide structure. The precursor- and occasionally the ACP-specificity of the ATs differ across the polyketide pathways and therefore, the ATs contribute to the structural diversity within this group of complex natural products. Those features make the AT enzymes one of the most promising tools for manipulation of polyketide assembly lines and generation of new polyketide compounds. However, the AT-based PKS engineering is still not straightforward and thus, rational design of functional PKSs requires detailed understanding of the complex machineries. This review summarizes the attempts of PKS engineering by exploiting the AT attributes for the modification of polyketide structures. The article includes 253 references and covers the most relevant literature published until May 2018.
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Affiliation(s)
- Ewa Maria Musiol-Kroll
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
| | - Wolfgang Wohlleben
- Interfakultäres Institut für Mikrobiologie und Infektionsmedizin, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
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18
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Miyanaga A, Ouchi R, Ishikawa F, Goto E, Tanabe G, Kudo F, Eguchi T. Structural Basis of Protein–Protein Interactions between a trans-Acting Acyltransferase and Acyl Carrier Protein in Polyketide Disorazole Biosynthesis. J Am Chem Soc 2018; 140:7970-7978. [DOI: 10.1021/jacs.8b04162] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Akimasa Miyanaga
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Risako Ouchi
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Fumihiro Ishikawa
- Faculty of Pharmacy, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
| | - Ena Goto
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Genzoh Tanabe
- Faculty of Pharmacy, Kindai University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan
| | - Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Tadashi Eguchi
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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19
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Klaus M, Grininger M. Engineering strategies for rational polyketide synthase design. Nat Prod Rep 2018; 35:1070-1081. [DOI: 10.1039/c8np00030a] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
In this review, we highlight strategies in engineering polyketide synthases (PKSs). We focus on important protein–protein interactions that constitute an intact PKS assembly line.
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Affiliation(s)
- Maja Klaus
- Institute of Organic Chemistry and Chemical Biology
- Buchmann Institute for Molecular Life Sciences
- Cluster of Excellence for Macromolecular Complexes
- Goethe University Frankfurt
- 60438 Frankfurt am Main
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology
- Buchmann Institute for Molecular Life Sciences
- Cluster of Excellence for Macromolecular Complexes
- Goethe University Frankfurt
- 60438 Frankfurt am Main
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20
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Miyanaga A. Structure and function of polyketide biosynthetic enzymes: various strategies for production of structurally diverse polyketides. Biosci Biotechnol Biochem 2017; 81:2227-2236. [DOI: 10.1080/09168451.2017.1391687] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
Polyketides constitute a large family of natural products that display various biological activities. Polyketides exhibit a high degree of structural diversity, although they are synthesized from simple acyl building blocks. Recent biochemical and structural studies provide a better understanding of the biosynthetic logic of polyketide diversity. This review highlights the biosynthetic mechanisms of structurally unique polyketides, β-amino acid-containing macrolactams, enterocin, and phenolic lipids. Functional and structural studies of macrolactam biosynthetic enzymes have revealed the unique biosynthetic machinery used for selective incorporation of a rare β-amino acid starter unit into the polyketide skeleton. Biochemical and structural studies of cyclization enzymes involved in the biosynthesis of enterocin and phenolic lipids provide mechanistic insights into how these enzymes diversify the carbon skeletons of their products.
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Affiliation(s)
- Akimasa Miyanaga
- Department of Chemistry, Tokyo Institute of Technology, Tokyo, Japan
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21
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Ronchi VP, Kim ED, Summa CM, Klein JM, Haas AL. In silico modeling of the cryptic E2∼ubiquitin-binding site of E6-associated protein (E6AP)/UBE3A reveals the mechanism of polyubiquitin chain assembly. J Biol Chem 2017; 292:18006-18023. [PMID: 28924046 DOI: 10.1074/jbc.m117.813477] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Indexed: 12/13/2022] Open
Abstract
To understand the mechanism for assembly of Lys48-linked polyubiquitin degradation signals, we previously demonstrated that the E6AP/UBE3A ligase harbors two functionally distinct E2∼ubiquitin-binding sites: a high-affinity Site 1 required for E6AP Cys820∼ubiquitin thioester formation and a canonical Site 2 responsible for subsequent chain elongation. Ordered binding to Sites 1 and 2 is here revealed by observation of UbcH7∼ubiquitin-dependent substrate inhibition of chain formation at micromolar concentrations. To understand substrate inhibition, we exploited the PatchDock algorithm to model in silico UbcH7∼ubiquitin bound to Site 1, validated by chain assembly kinetics of selected point mutants. The predicted structure buries an extensive solvent-excluded surface bringing the UbcH7∼ubiquitin thioester bond within 6 Å of the Cys820 nucleophile. Modeling onto the active E6AP trimer suggests that substrate inhibition arises from steric hindrance between Sites 1 and 2 of adjacent subunits. Confirmation that Sites 1 and 2 function in trans was demonstrated by examining the effect of E6APC820A on wild-type activity and single-turnover pulse-chase kinetics. A cyclic proximal indexation model proposes that Sites 1 and 2 function in tandem to assemble thioester-linked polyubiquitin chains from the proximal end attached to Cys820 before stochastic en bloc transfer to the target protein. Non-reducing SDS-PAGE confirms assembly of the predicted Cys820-linked 125I-polyubiquitin thioester intermediate. Other studies suggest that Glu550 serves as a general base to generate the Cys820 thiolate within the low dielectric binding interface and Arg506 functions to orient Glu550 and to stabilize the incipient anionic transition state during thioester exchange.
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Affiliation(s)
| | - Elizabeth D Kim
- From the Department of Biochemistry and Molecular Biology and
| | - Christopher M Summa
- the Department of Computer Science, University of New Orleans, New Orleans, Louisiana 70148
| | | | - Arthur L Haas
- From the Department of Biochemistry and Molecular Biology and .,the Stanley S. Scott Cancer Center, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112 and
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22
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Ad O, Thuronyi BW, Chang MCY. Elucidating the mechanism of fluorinated extender unit loading for improved production of fluorine-containing polyketides. Proc Natl Acad Sci U S A 2017; 114:E660-E668. [PMID: 28096394 PMCID: PMC5293041 DOI: 10.1073/pnas.1614196114] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polyketides are a large family of bioactive natural products synthesized by polyketide synthase (PKS) enzyme complexes predominantly from acetate and propionate. Given the structural diversity of compounds produced using these two simple building blocks, there has been longstanding interest in engineering the incorporation of alternative extender units. We have been investigating the mechanism of fluorinated monomer insertion by three of the six different modules of the PKS involved in erythromycin biosynthesis (6-deoxyerythronolide B synthase, DEBS) to begin understanding the contribution of different steps, such as enzyme acylation, transacylation, C-C bond formation, and chain transfer, to the overall selectivity and efficiency of this process. In these studies, we observe that inactivation of a cis-acyltransferase (AT) domain to circumvent its native extender unit preference leads concurrently to a change of mechanism in which chain extension with fluorine-substituted extender units switches largely to an acyl carrier protein (ACP)-independent mode. This result suggests that the covalent linkage between the growing polyketide chain and the enzyme is lost in these cases, which would limit efficient chain elongation after insertion of a fluorinated monomer. However, use of a standalone trans-acting AT to complement modules with catalytically deficient AT domains leads to enzyme acylation with the fluoromalonyl-CoA extender unit. Formation of the canonical ACP-linked intermediate with fluoromalonyl-CoA allows insertion of fluorinated extender units at 43% of the yield of the wild-type system while also amplifying product yield in single chain-extension experiments and enabling multiple chain extensions to form multiply fluorinated products.
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Affiliation(s)
- Omer Ad
- Department of Chemistry, University of California, Berkeley, CA 94720-1460
| | - B W Thuronyi
- Department of Chemistry, University of California, Berkeley, CA 94720-1460
| | - Michelle C Y Chang
- Department of Chemistry, University of California, Berkeley, CA 94720-1460;
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-1460
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23
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Abstract
This highlight provides an overview of recent advances in understanding the diversity of polyketide synthase (PKS) substrate building blocks. Substrates functioning as starter units and extender units contribute significantly to the chemical complexity and structural diversity exhibited by this class of natural products. This article complements and extends upon the current comprehensive reviews that have been published on these two topics (Moore and Hertweck, Nat. Prod. Rep., 2002, 19, 70; Chan et al., Nat. Prod. Rep., 2009, 1, 90; Wilson and Moore, Nat. Prod. Rep., 2012, 29, 72).
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Affiliation(s)
- Lauren Ray
- Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0204, USA.
| | - Bradley S Moore
- Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0204, USA. and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093-0204, USA
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24
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Structure-based analysis of the molecular interactions between acyltransferase and acyl carrier protein in vicenistatin biosynthesis. Proc Natl Acad Sci U S A 2016; 113:1802-7. [PMID: 26831085 DOI: 10.1073/pnas.1520042113] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Acyltransferases (ATs) are key determinants of building block specificity in polyketide biosynthesis. Despite the importance of protein-protein interactions between AT and acyl carrier protein (ACP) during the acyltransfer reaction, the mechanism of ACP recognition by AT is not understood in detail. Herein, we report the crystal structure of AT VinK, which transfers a dipeptide group between two ACPs, VinL and VinP1LdACP, in vicenistatin biosynthesis. The isolated VinK structure showed a unique substrate-binding pocket for the dipeptide group linked to ACP. To gain greater insight into the mechanism of ACP recognition, we attempted to crystallize the VinK-ACP complexes. Because transient enzyme-ACP complexes are difficult to crystallize, we developed a covalent cross-linking strategy using a bifunctional maleimide reagent to trap the VinK-ACP complexes, allowing the determination of the crystal structure of the VinK-VinL complex. In the complex structure, Arg-153, Met-206, and Arg-299 of VinK interact with the negatively charged helix II region of VinL. The VinK-VinL complex structure allows, to our knowledge, the first visualization of the interaction between AT and ACP and provides detailed mechanistic insights into ACP recognition by AT.
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25
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Helfrich EJN, Piel J. Biosynthesis of polyketides by trans-AT polyketide synthases. Nat Prod Rep 2016; 33:231-316. [DOI: 10.1039/c5np00125k] [Citation(s) in RCA: 230] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This review discusses the biosynthesis of natural products that are generated bytrans-AT polyketide synthases, a family of catalytically versatile enzymes that represents one of the major group of proteins involved in the production of bioactive polyketides.
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Affiliation(s)
- Eric J. N. Helfrich
- Institute of Microbiology
- Eidgenössische Technische Hochschule (ETH) Zurich
- 8093 Zurich
- Switzerland
| | - Jörn Piel
- Institute of Microbiology
- Eidgenössische Technische Hochschule (ETH) Zurich
- 8093 Zurich
- Switzerland
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26
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Metabolic engineering of Escherichia coli for the biosynthesis of 2-pyrrolidone. Metab Eng Commun 2015; 3:1-7. [PMID: 29468109 PMCID: PMC5779725 DOI: 10.1016/j.meteno.2015.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 10/25/2015] [Accepted: 11/03/2015] [Indexed: 11/23/2022] Open
Abstract
2-Pyrrolidone is a valuable bulk chemical with myriad applications as a solvent, polymer precursor and active pharmaceutical intermediate. A novel 2-pyrrolidone synthase, ORF27, from Streptomyces aizunensis was identified to catalyze the ring closing dehydration of γ-aminobutyrate. ORF27's tendency to aggregate was resolved by expression at low temperature and fusion to the maltose binding protein (MBP). Recombinant Escherichia coli was metabolically engineered for the production of 2-pyrrolidone from glutamate by expressing both the genes encoding GadB, a glutamate decarboxylase, and ORF27. Incorporation of a GadB mutant lacking H465 and T466, GadB_ΔHT, improved the efficiency of one-pot 2-pyrrolidone biosynthesis in vivo. When the recombinant E. coli strain expressing the E. coli GadB_ΔHT mutant and the ORF27-MBP fusion was cultured in ZYM-5052 medium containing 9 g/L of l-glutamate, 7.7 g/L of l-glutamate was converted to 1.1 g/L of 2-pyrrolidone within 31 h, achieving 25% molar yield from the consumed substrate. ORF27 from Streptomyces aizunensis catalyzes formation of 2-pyrrolidone from γ-aminobutyrate. Recombinant Escherichia coli with GadB and ORF27 produces 2-pyrrolidone from glutamate. Engineered strain capable of producing 1.1 g/L of 2-pyrrolidone from 9 g/L of glutamate within 31 h.
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27
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Winter JM, Cascio D, Dietrich D, Sato M, Watanabe K, Sawaya MR, Vederas JC, Tang Y. Biochemical and Structural Basis for Controlling Chemical Modularity in Fungal Polyketide Biosynthesis. J Am Chem Soc 2015; 137:9885-93. [PMID: 26172141 DOI: 10.1021/jacs.5b04520] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Modular collaboration between iterative fungal polyketide synthases (IPKSs) is an important mechanism for generating structural diversity of polyketide natural products. Inter-PKS communication and substrate channeling are controlled in large by the starter unit acyl carrier protein transacylase (SAT) domain found in the accepting IPKS module. Here, we reconstituted the modular biosynthesis of the benzaldehyde core of the chaetoviridin and chaetomugilin azaphilone natural products using the IPKSs CazF and CazM. Our studies revealed a critical role of CazM's SAT domain in selectively transferring a highly reduced triketide product from CazF. In contrast, a more oxidized triketide that is also produced by CazF and required in later stages of biosynthesis of the final product is not recognized by the SAT domain. The structural basis for the acyl unit selectivity was uncovered by the first X-ray structure of a fungal SAT domain, highlighted by a covalent hexanoyl thioester intermediate in the SAT active site. The crystal structure of SAT domain will enable protein engineering efforts aimed at mixing and matching different IPKS modules for the biosynthesis of new compounds.
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Affiliation(s)
- Jaclyn M Winter
- †Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, United States
| | - Duilio Cascio
- §Department of Energy (DOE) Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095, United States
| | - David Dietrich
- ∥Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Michio Sato
- ⊥Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Kenji Watanabe
- ⊥Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Michael R Sawaya
- §Department of Energy (DOE) Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095, United States
| | - John C Vederas
- ∥Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yi Tang
- †Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, United States.,‡Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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28
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Lowry B, Walsh CT, Khosla C. In Vitro Reconstitution of Metabolic Pathways: Insights into Nature's Chemical Logic. Synlett 2015; 26:1008-1025. [PMID: 26207083 PMCID: PMC4507746 DOI: 10.1055/s-0034-1380264] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In vitro analysis of metabolic pathways is becoming a powerful method to gain a deeper understanding of Nature's core biochemical transformations. With astounding advancements in biotechnology, purification of a metabolic pathway's constitutive enzymatic components is becoming a tractable problem, and such in vitro studies allow scientists to capture the finer details of enzymatic reaction mechanisms, kinetics, and the identity of organic product molecules. In this review, we present eleven metabolic pathways that have been the subject of in vitro reconstitution studies in the literature in recent years. In addition, we have selected and analyzed subset of four case studies within these eleven examples that exemplify remarkable organic chemistry occurring within biology. These examples serves as tangible reminders that Nature's biochemical routes obey the fundamental principles of organic chemistry, and the chemical mechanisms are reminiscent of those featured in traditional synthetic organic routes. The illustrations of biosynthetic chemistry depicted in this review may inspire the development of biomimetic chemistries via abiotic chemical techniques.
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Affiliation(s)
- Brian Lowry
- Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA;
| | - Christopher T Walsh
- Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford University, 443 Via Ortega, Stanford, CA 94305
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA; ; Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford University, 443 Via Ortega, Stanford, CA 94305 ; Department of Chemistry, 333 Campus Drive Mudd Building, Stanford University, Stanford, CA 94305, USA;
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29
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Randall SM, Koryakina I, Williams GJ, Muddiman DC. Evaluating nonpolar surface area and liquid chromatography/mass spectrometry response: an application for site occupancy measurements for enzyme intermediates in polyketide biosynthesis. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:2511-2522. [PMID: 25366398 PMCID: PMC4230892 DOI: 10.1002/rcm.7051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 08/22/2014] [Accepted: 09/09/2014] [Indexed: 05/31/2023]
Abstract
RATIONALE Site occupancy measurements using liquid chromatography/mass spectrometry (LC/MS) are reported throughout the literature. However, site occupancy quantification suffers from ionization bias between modified and unmodified peptides containing the active site. In this study, we explore the MS signal as a function of nonpolar surface area (NPSA) in order to better understand this bias in electrospray response. The correlation between hydrophobicity and LC/MS response was evaluated and applied to study enzyme intermediates in polyketide synthases. METHODS Site occupancy methods were developed to study acyltransferase activity. To further evaluate these methods, several standard peptides containing one cysteine residue were modified with alkylation reagents of increasing hydrophobicity to study the MS signal as a function of NPSA. RESULTS A consistent trend in MS response was observed which is dependent on the NPSA of the analyte. An optimal NPSA zone was observed for the peptides studied. CONCLUSIONS Nonpolar surface area can be used as metric to determine relative LC/MS response for peptides and evaluate site occupancy measurements.
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Affiliation(s)
- Shan M. Randall
- W.M. Keck Fourier Transform Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Irina Koryakina
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - Gavin J. Williams
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - David C. Muddiman
- W.M. Keck Fourier Transform Mass Spectrometry Laboratory, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, USA
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30
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Structural rearrangements of a polyketide synthase module during its catalytic cycle. Nature 2014; 510:560-4. [PMID: 24965656 PMCID: PMC4074775 DOI: 10.1038/nature13409] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 04/28/2014] [Indexed: 12/12/2022]
Abstract
The polyketide synthase (PKS) mega-enzyme assembly line uses a modular architecture to synthesize diverse and bioactive natural products that often constitute the core structures or complete chemical entities for many clinically approved therapeutic agents. The architecture of a full-length PKS module from the pikromycin pathway of Streptomyces venezuelae creates a reaction chamber for the intramodule acyl carrier protein (ACP) domain that carries building blocks and intermediates between acyltransferase, ketosynthase and ketoreductase active sites (see accompanying paper). Here we determine electron cryo-microscopy structures of a full-length pikromycin PKS module in three key biochemical states of its catalytic cycle. Each biochemical state was confirmed by bottom-up liquid chromatography/Fourier transform ion cyclotron resonance mass spectrometry. The ACP domain is differentially and precisely positioned after polyketide chain substrate loading on the active site of the ketosynthase, after extension to the β-keto intermediate, and after β-hydroxy product generation. The structures reveal the ACP dynamics for sequential interactions with catalytic domains within the reaction chamber, and for transferring the elongated and processed polyketide substrate to the next module in the PKS pathway. During the enzymatic cycle the ketoreductase domain undergoes dramatic conformational rearrangements that enable optimal positioning for reductive processing of the ACP-bound polyketide chain elongation intermediate. These findings have crucial implications for the design of functional PKS modules, and for the engineering of pathways to generate pharmacologically relevant molecules.
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31
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Dunn BJ, Watts KR, Robbins T, Cane DE, Khosla C. Comparative analysis of the substrate specificity of trans- versus cis-acyltransferases of assembly line polyketide synthases. Biochemistry 2014; 53:3796-806. [PMID: 24871074 PMCID: PMC4067149 DOI: 10.1021/bi5004316] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Due
to their pivotal role in extender unit selection during polyketide
biosynthesis, acyltransferase (AT) domains are important engineering
targets. A subset of assembly line polyketide synthases (PKSs) are
serviced by discrete, trans-acting ATs. Theoretically,
these trans-ATs can complement an inactivated cis-AT, promoting introduction of a noncognate extender
unit. This approach requires a better understanding of the substrate
specificity and catalytic mechanism of naturally occurring trans-ATs. We kinetically analyzed trans-ATs from the disorazole and kirromycin synthases and compared them
to a representative cis-AT from the 6-deoxyerythronolide
B synthase (DEBS). During transacylation, the disorazole AT favored
malonyl-CoA over methylmalonyl-CoA by >40000-fold, whereas the
kirromycin
AT favored ethylmalonyl-CoA over methylmalonyl-CoA by 20-fold. Conversely,
the disorazole AT had broader specificity than its kirromycin counterpart
for acyl carrier protein (ACP) substrates. The presence of the ACP
had little effect on the specificity (kcat/KM) of the cis-AT domain
for carboxyacyl-CoA substrates but had a marked influence on the corresponding
specificity parameters for the trans-ATs, suggesting
that these enzymes do not act strictly by a canonical ping-pong mechanism.
To investigate the relevance of the kinetic analysis of isolated ATs
in the context of intact PKSs, we complemented an in vitro AT-null DEBS assembly line with either trans-AT.
Whereas the disorazole AT efficiently complemented the mutant PKS
at substoichiometric protein ratios, the kirromycin AT was considerably
less effective. Our findings suggest that knowledge of both carboxyacyl-CoA
and ACP specificity is critical to the choice of a trans-AT in combination with a mutant PKS to generate novel polyketides.
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Affiliation(s)
- Briana J Dunn
- Department of Chemical Engineering, ‡Department of Chemistry, and ∥Department of Biochemistry, Stanford University , Stanford, California 94305, United States
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32
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Ye Z, Musiol EM, Weber T, Williams GJ. Reprogramming acyl carrier protein interactions of an Acyl-CoA promiscuous trans-acyltransferase. ACTA ACUST UNITED AC 2014; 21:636-46. [PMID: 24726832 DOI: 10.1016/j.chembiol.2014.02.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Revised: 01/27/2014] [Accepted: 02/06/2014] [Indexed: 11/29/2022]
Abstract
Protein interactions between acyl carrier proteins (ACPs) and trans-acting acyltransferase domains (trans-ATs) are critical for regioselective extender unit installation by many polyketide synthases, yet little is known regarding the specificity of these interactions, particularly for trans-ATs with unusual extender unit specificities. Currently, the best-studied trans-AT with nonmalonyl specificity is KirCII from kirromycin biosynthesis. Here, we developed an assay to probe ACP interactions based on leveraging the extender unit promiscuity of KirCII. The assay allows us to identify residues on the ACP surface that contribute to specific recognition by KirCII. This information proved sufficient to modify a noncognate ACP from a different biosynthetic system to be a substrate for KirCII. The findings form a foundation for further understanding the specificity of trans-AT:ACP protein interactions and for engineering modular polyketide synthases to produce analogs.
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Affiliation(s)
- Zhixia Ye
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA
| | - Ewa M Musiol
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany; German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Tilmann Weber
- Interfaculty Institute of Microbiology and Infection Medicine, Eberhard Karls University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany; German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Gavin J Williams
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA.
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33
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Walker MC, Thuronyi BW, Charkoudian LK, Lowry B, Khosla C, Chang MCY. Expanding the fluorine chemistry of living systems using engineered polyketide synthase pathways. Science 2013; 341:1089-94. [PMID: 24009388 PMCID: PMC4057101 DOI: 10.1126/science.1242345] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Organofluorines represent a rapidly expanding proportion of molecules that are used in pharmaceuticals, diagnostics, agrochemicals, and materials. Despite the prevalence of fluorine in synthetic compounds, the known biological scope is limited to a single pathway that produces fluoroacetate. Here, we demonstrate that this pathway can be exploited as a source of fluorinated building blocks for introduction of fluorine into natural-product scaffolds. Specifically, we have constructed pathways involving two polyketide synthase systems, and we show that fluoroacetate can be used to incorporate fluorine into the polyketide backbone in vitro. We further show that fluorine can be inserted site-selectively and introduced into polyketide products in vivo. These results highlight the prospects for the production of complex fluorinated natural products using synthetic biology.
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Affiliation(s)
- Mark C. Walker
- Departments of Chemistry and Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720-1460
| | - Benjamin W. Thuronyi
- Departments of Chemistry and Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720-1460
| | - Louise K. Charkoudian
- Departments of Chemistry, Chemical Engineering, and Biochemistry, Stanford University, Stanford, CA 94305
| | - Brian Lowry
- Departments of Chemistry, Chemical Engineering, and Biochemistry, Stanford University, Stanford, CA 94305
| | - Chaitan Khosla
- Departments of Chemistry, Chemical Engineering, and Biochemistry, Stanford University, Stanford, CA 94305
| | - Michelle C. Y. Chang
- Departments of Chemistry and Molecular & Cell Biology, University of California, Berkeley, Berkeley, CA 94720-1460
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34
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Musiol EM, Greule A, Härtner T, Kulik A, Wohlleben W, Weber T. The AT₂ domain of KirCI loads malonyl extender units to the ACPs of the kirromycin PKS. Chembiochem 2013; 14:1343-52. [PMID: 23828654 DOI: 10.1002/cbic.201300211] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Indexed: 11/06/2022]
Abstract
The antibiotic kirromycin is assembled by a hybrid modular polyketide synthases (PKSs)/nonribosomal peptide synthetases (NRPSs). Five of six PKSs of this complex assembly line do not have acyltransferase (AT) and have to recruit this activity from discrete AT enzymes. Here, we show that KirCI is a discrete AT which is involved in kirromycin production and displays a rarely found three-domain architecture (AT₁-AT₂-ER). We demonstrate that the second AT domain, KirCI-AT₂, but not KirCI-AT₁, is the malonyl-CoA-specific AT which utilizes this precursor for loading the acyl carrier proteins (ACPs) of the trans-AT PKS in vitro. In the kirromycin biosynthetic pathway, ACP5 is exclusively loaded with ethylmalonate by the enzyme KirCII and is not recognized as a substrate by KirCI. Interestingly, the excised KirCI-AT₂ can also transfer malonate to ACP5 and thus has a relaxed ACP-specificity compared to the entire KirCI protein. The ability of KirCI-AT₂ to load different ACPs provides opportunities for AT engineering as a potential strategy for polyketide diversification.
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Affiliation(s)
- Ewa Maria Musiol
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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35
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Dunn BJ, Khosla C. Engineering the acyltransferase substrate specificity of assembly line polyketide synthases. J R Soc Interface 2013; 10:20130297. [PMID: 23720536 DOI: 10.1098/rsif.2013.0297] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Polyketide natural products act as a broad range of therapeutics, including antibiotics, immunosuppressants and anti-cancer agents. This therapeutic diversity stems from the structural diversity of these small molecules, many of which are produced in an assembly line manner by modular polyketide synthases. The acyltransferase (AT) domains of these megasynthases are responsible for selection and incorporation of simple monomeric building blocks, and are thus responsible for a large amount of the resulting polyketide structural diversity. The substrate specificity of these domains is often targeted for engineering in the generation of novel, therapeutically active natural products. This review outlines recent developments that can be used in the successful engineering of these domains, including AT sequence and structural data, mechanistic insights and the production of a diverse pool of extender units. It also provides an overview of previous AT domain engineering attempts, and concludes with proposed engineering approaches that take advantage of current knowledge. These approaches may lead to successful production of biologically active 'unnatural' natural products.
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Affiliation(s)
- Briana J Dunn
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
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36
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Koryakina I, McArthur J, Randall S, Draelos MM, Musiol EM, Muddiman DC, Weber T, Williams GJ. Poly specific trans-acyltransferase machinery revealed via engineered acyl-CoA synthetases. ACS Chem Biol 2013; 8:200-8. [PMID: 23083014 DOI: 10.1021/cb3003489] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Polyketide synthases construct polyketides with diverse structures and biological activities via the condensation of extender units and acyl thioesters. Although a growing body of evidence suggests that polyketide synthases might be tolerant to non-natural extender units, in vitro and in vivo studies aimed at probing and utilizing polyketide synthase specificity are severely limited to only a small number of extender units, owing to the lack of synthetic routes to a broad variety of acyl-CoA extender units. Here, we report the construction of promiscuous malonyl-CoA synthetase variants that can be used to synthesize a broad range of malonyl-CoA extender units substituted at the C2-position, several of which contain handles for chemoselective ligation and are not found in natural biosynthetic systems. We highlighted utility of these enzymes by probing the acyl-CoA specificity of several trans-acyltransferases, leading to the unprecedented discovery of poly specificity toward non-natural extender units, several of which are not found in naturally occurring biosynthetic pathways. These results reveal that polyketide biosynthetic machinery might be more tolerant to non-natural substrates than previously established, and that mutant synthetases are valuable tools for probing the specificity of biosynthetic machinery. Our data suggest new synthetic biology strategies for harnessing this promiscuity and enabling the regioselective modification of polyketides.
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Affiliation(s)
| | | | | | | | - Ewa M. Musiol
- Eberhard-Karls-Universität Tübingen, Interfakultäres Institut für
Mikrobiologie und Infektionsmedizin, Mikrobiologie/Biotechnologie,
Tübingen, Germany
| | | | - Tilmann Weber
- Eberhard-Karls-Universität Tübingen, Interfakultäres Institut für
Mikrobiologie und Infektionsmedizin, Mikrobiologie/Biotechnologie,
Tübingen, Germany
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37
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Yadav G, Anand S, Mohanty D. Prediction of inter domain interactions in modular polyketide synthases by docking and correlated mutation analysis. J Biomol Struct Dyn 2013; 31:17-29. [DOI: 10.1080/07391102.2012.691342] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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38
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Xu W, Qiao K, Tang Y. Structural analysis of protein-protein interactions in type I polyketide synthases. Crit Rev Biochem Mol Biol 2012; 48:98-122. [PMID: 23249187 DOI: 10.3109/10409238.2012.745476] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Polyketide synthases (PKSs) are responsible for synthesizing a myriad of natural products with agricultural, medicinal relevance. The PKSs consist of multiple functional domains of which each can catalyze a specified chemical reaction leading to the synthesis of polyketides. Biochemical studies showed that protein-substrate and protein-protein interactions play crucial roles in these complex regio-/stereo-selective biochemical processes. Recent developments on X-ray crystallography and protein NMR techniques have allowed us to understand the biosynthetic mechanism of these enzymes from their structures. These structural studies have facilitated the elucidation of the sequence-function relationship of PKSs and will ultimately contribute to the prediction of product structure. This review will focus on the current knowledge of type I PKS structures and the protein-protein interactions in this system.
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Affiliation(s)
- Wei Xu
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
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39
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Yuzawa S, Kim W, Katz L, Keasling JD. Heterologous production of polyketides by modular type I polyketide synthases in Escherichia coli. Curr Opin Biotechnol 2012; 23:727-35. [DOI: 10.1016/j.copbio.2011.12.029] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 12/19/2011] [Accepted: 12/21/2011] [Indexed: 11/15/2022]
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40
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Crosby J, Crump MP. The structural role of the carrier protein--active controller or passive carrier. Nat Prod Rep 2012; 29:1111-37. [PMID: 22930263 DOI: 10.1039/c2np20062g] [Citation(s) in RCA: 132] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Common to all FASs, PKSs and NRPSs is a remarkable component, the acyl or peptidyl carrier protein (A/PCP). These take the form of small individual proteins in type II systems or discrete folded domains in the multi-domain type I systems and are characterized by a fold consisting of three major α-helices and between 60-100 amino acids. This protein is central to these biosynthetic systems and it must bind and transport a wide variety of functionalized ligands as well as mediate numerous protein-protein interactions, all of which contribute to efficient enzyme turnover. This review covers the structural and biochemical characterization of carrier proteins, as well as assessing their interactions with different ligands, and other synthase components. Finally, their role as an emerging tool in biotechnology is discussed.
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Affiliation(s)
- John Crosby
- School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK
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41
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Bučević-Popović V, Šprung M, Soldo B, Pavela-Vrančič M. The A9 Core Sequence from NRPS Adenylation Domain Is Relevant for Thioester Formation. Chembiochem 2012; 13:1913-20. [DOI: 10.1002/cbic.201200309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Indexed: 11/11/2022]
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42
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Bergeret F, Gavalda S, Chalut C, Malaga W, Quémard A, Pedelacq JD, Daffé M, Guilhot C, Mourey L, Bon C. Biochemical and structural study of the atypical acyltransferase domain from the mycobacterial polyketide synthase Pks13. J Biol Chem 2012; 287:33675-90. [PMID: 22825853 DOI: 10.1074/jbc.m111.325639] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pks13 is a type I polyketide synthase involved in the final biosynthesis step of mycolic acids, virulence factors, and essential components of the Mycobacterium tuberculosis envelope. Here, we report the biochemical and structural characterization of a 52-kDa fragment containing the acyltransferase domain of Pks13. This fragment retains the ability to load atypical extender units, unusually long chain acyl-CoA with a predilection for carboxylated substrates. High resolution crystal structures were determined for the apo, palmitoylated, and carboxypalmitoylated forms. Structural conservation with type I polyketide synthases and related fatty-acid synthases also extends to the interdomain connections. Subtle changes could be identified both in the active site and in the upstream and downstream linkers in line with the organization displayed by this singular polyketide synthase. More importantly, the crystallographic analysis illustrated for the first time how a long saturated chain can fit in the core structure of an acyltransferase domain through a dedicated channel. The structures also revealed the unexpected binding of a 12-mer peptide that might provide insight into domain-domain interaction.
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Affiliation(s)
- Fabien Bergeret
- Institut de Pharmacologie et de Biologie Structurale (IPBS), CNRS, Toulouse, France
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43
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Liew CW, Nilsson M, Chen MW, Sun H, Cornvik T, Liang ZX, Lescar J. Crystal structure of the acyltransferase domain of the iterative polyketide synthase in enediyne biosynthesis. J Biol Chem 2012; 287:23203-15. [PMID: 22589546 DOI: 10.1074/jbc.m112.362210] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Biosynthesis of the enediyne natural product dynemicin in Micromonospora chersina is initiated by DynE8, a highly reducing iterative type I polyketide synthase that assembles polyketide intermediates from the acetate units derived solely from malonyl-CoA. To understand the substrate specificity and the evolutionary relationship between the acyltransferase (AT) domains of DynE8, fatty acid synthase, and modular polyketide synthases, we overexpressed a 44-kDa fragment of DynE8 (hereafter named AT(DYN10)) encompassing its entire AT domain and the adjacent linker domain. The crystal structure at 1.4 Å resolution unveils a α/β hydrolase and a ferredoxin-like subdomain with the Ser-His catalytic dyad located in the cleft between the two subdomains. The linker domain also adopts a α/β fold abutting the AT catalytic domain. Co-crystallization with malonyl-CoA yielded a malonyl-enzyme covalent complex that most likely represents the acyl-enzyme intermediate. The structure explains the preference for malonyl-CoA with a conserved arginine orienting the carboxylate group of malonate and several nonpolar residues that preclude α-alkyl malonyl-CoA binding. Co-crystallization with acetyl-CoA revealed two noncovalently bound acetates generated by the enzymatic hydrolysis of acetyl-CoA that acts as an inhibitor for DynE8. This suggests that the AT domain can upload the acyl groups from either malonyl-CoA or acetyl-CoA onto the catalytic Ser(651) residue. However, although the malonyl group can be transferred to the acyl carrier protein domain, transfer of the acetyl group to the acyl carrier protein domain is suppressed. Local structural differences may account for the different stability of the acyl-enzyme intermediates.
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Affiliation(s)
- Chong Wai Liew
- School of Biological Sciences, Nanyang Technological University, Singapore 637551
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44
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Condurso HL, Bruner SD. Structure guided approaches toward exploiting and manipulating nonribosomal peptide and polyketide biosynthetic pathways. Curr Opin Chem Biol 2012; 16:162-9. [DOI: 10.1016/j.cbpa.2012.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 01/31/2012] [Accepted: 02/02/2012] [Indexed: 11/28/2022]
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45
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Prasad G, Amoroso JW, Borketey LS, Schnarr NA. N-activated β-lactams as versatile reagents for acyl carrier protein labeling. Org Biomol Chem 2012; 10:1992-2002. [PMID: 22293823 DOI: 10.1039/c2ob06846j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Acyl carrier proteins are critical components of fatty acid and polyketide biosynthesis. Their primary function is to shuttle intermediates between active sites via a covalently bound phosphopantetheine arm. Small molecules capable of acylating this prosthetic group will provide a simple and reversible means of introducing novel functionality onto carrier protein domains. A series of N-activated β-lactams are prepared to examine site-specific acylation of the phosphopantetheine-thiol. In general, β-lactams are found to be significantly more reactive than our previously studied β-lactones. Selectivity for the holo over apo-form of acyl carrier proteins is demonstrated indicating that only the phosphopantetheine-thiol is modified. Incorporation of an N-propargyloxycarbonyl group provides an alkyne handle for conjugation to fluorophores and affinity labels. The utility of these groups for mechanistic interrogation of a critical step in polyketide biosynthesis is examined through comparison to traditional probes. In all, we expect the probes described in this study to serve as valuable and versatile tools for mechanistic interrogation.
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Affiliation(s)
- Gitanjeli Prasad
- Department of Chemistry, University of Massachusetts, 710 N. Pleasant Street, Amherst, Massachusetts 01003, USA
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46
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Musiol EM, Weber T. Discrete acyltransferases involved in polyketide biosynthesis. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20048a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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47
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Wong FT, Jin X, Mathews II, Cane DE, Khosla C. Structure and mechanism of the trans-acting acyltransferase from the disorazole synthase. Biochemistry 2011; 50:6539-48. [PMID: 21707057 DOI: 10.1021/bi200632j] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The 1.51 Å resolution X-ray crystal structure of the trans-acyltransferase (AT) from the "AT-less" disorazole synthase (DSZS) and that of its acetate complex at 1.35 Å resolution are reported. Separately, comprehensive alanine-scanning mutagenesis of one of its acyl carrier protein substrates (ACP1 from DSZS) led to the identification of a conserved Asp45 residue on the ACP, which contributes to the substrate specificity of this unusual enzyme. Together, these experimental findings were used to derive a model for the selective association of the DSZS AT and its ACP substrate. With a goal of structurally characterizing the AT-ACP interface, a strategy was developed for covalently cross-linking the active site Ser → Cys mutant of the DSZS AT to its ACP substrate and for purifying the resulting AT-ACP complex to homogeneity. The S86C DSZS AT mutant was found to be functional, albeit with a transacylation efficiency 200-fold lower than that of its wild-type counterpart. Our findings provide new insights as well as new opportunities for high-resolution analysis of an important protein-protein interface in polyketide synthases.
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Affiliation(s)
- Fong T Wong
- Department of Chemical Engineering, Department of Chemistry, and §Department of Biochemistry, Stanford University , Stanford, California 94305, United States
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Molecular recognition between ketosynthase and acyl carrier protein domains of the 6-deoxyerythronolide B synthase. Proc Natl Acad Sci U S A 2010; 107:22066-71. [PMID: 21127271 DOI: 10.1073/pnas.1014081107] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Every polyketide synthase module has an acyl carrier protein (ACP) and a ketosynthase (KS) domain that collaborate to catalyze chain elongation. The same ACP then engages the KS domain of the next module to facilitate chain transfer. Understanding the mechanism for this orderly progress of the growing polyketide chain represents a fundamental challenge in assembly line enzymology. Using both experimental and computational approaches, the molecular basis for KS-ACP interactions in the 6-deoxyerythronolide B synthase has been decoded. Surprisingly, KS-ACP recognition is controlled at different interfaces during chain elongation versus chain transfer. In fact, chain elongation is controlled at a docking site remote from the catalytic center. Not only do our findings reveal a new principle in the modular control of polyketide antibiotic biosynthesis, they also provide a rationale for the mandatory homodimeric structure of polyketide synthases, in contrast to the monomeric nonribosomal peptide synthetases.
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Zheng J, Taylor CA, Piasecki SK, Keatinge-Clay AT. Structural and Functional Analysis of A-Type Ketoreductases from the Amphotericin Modular Polyketide Synthase. Structure 2010; 18:913-22. [DOI: 10.1016/j.str.2010.04.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Revised: 04/19/2010] [Accepted: 04/22/2010] [Indexed: 01/10/2023]
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50
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Tran L, Broadhurst RW, Tosin M, Cavalli A, Weissman KJ. Insights into Protein-Protein and Enzyme-Substrate Interactions in Modular Polyketide Synthases. ACTA ACUST UNITED AC 2010; 17:705-16. [DOI: 10.1016/j.chembiol.2010.05.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 04/26/2010] [Accepted: 05/03/2010] [Indexed: 11/29/2022]
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