1
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Zhang DK, Song KY, Yan YQ, Zheng JT, Xu J, Da LT, Xu MJ. Structural and mechanistic investigations on CC bond forming α-oxoamine synthase allowing L-glutamate as substrate. Int J Biol Macromol 2024; 268:131696. [PMID: 38642679 DOI: 10.1016/j.ijbiomac.2024.131696] [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: 01/07/2024] [Revised: 03/23/2024] [Accepted: 04/17/2024] [Indexed: 04/22/2024]
Abstract
Carbon‑carbon (C-C) bonds serve as the fundamental structural backbone of organic molecules. As a critical CC bond forming enzyme, α-oxoamine synthase is responsible for the synthesis of α-amino ketones by performing the condensation reaction between amino acids and acyl-CoAs. We previously identified an α-oxoamine synthase (AOS), named as Alb29, involved in albogrisin biosynthesis in Streptomyces albogriseolus MGR072. This enzyme belongs to the α-oxoamine synthase family, a subfamily under the pyridoxal 5'-phosphate (PLP) dependent enzyme superfamily. In this study, we report the crystal structures of Alb29 bound to PLP and L-Glu, which provide the atomic-level structural insights into the substrate recognition by Alb29. We discover that Alb29 can catalyze the amino transformation from L-Gln to L-Glu, besides the condensation of L-Glu with β-methylcrotonyl coenzyme A. Subsequent structural analysis has revealed that one flexible loop in Alb29 plays an important role in both amino transformation and condensation. Based on the crystal structure of the S87G mutant in the loop region, we capture two distinct conformations of the flexible loop in the active site, compared with the wild-type Alb29. Our study offers valuable insights into the catalytic mechanism underlying substrate recognition of Alb29.
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Affiliation(s)
- Dai-Ke Zhang
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Kai-Yuan Song
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Ya-Qian Yan
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Jian-Ting Zheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Jun Xu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Lin-Tai Da
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
| | - Min-Juan Xu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.
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2
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Ogonkov A, Dieterich CL, Meoded RA, Piel J, Fraley AE, Sasso S. Characterization of an Unusual α-Oxoamine Synthase Off-Loading Domain from a Cyanobacterial Type I Fatty Acid Synthase. Chembiochem 2023; 24:e202300209. [PMID: 37144248 DOI: 10.1002/cbic.202300209] [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: 03/17/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 05/06/2023]
Abstract
Type I fatty acid synthases (FASs) are known from higher eukaryotes and fungi. We report the discovery of FasT, a rare type I FAS from the cyanobacterium Chlorogloea sp. CCALA695. FasT possesses an unusual off-loading domain, which was heterologously expressed in E. coli and found to act as an α-oxoamine synthase (AOS) in vitro. Similar to serine palmitoyltransferases from sphingolipid biosynthesis, the AOS off-loading domain catalyzes a decarboxylative Claisen condensation between l-serine and a fatty acyl thioester. While the AOS domain was strictly specific for l-serine, thioesters with saturated fatty acyl chains of six carbon atoms and longer were tolerated, with the highest activity observed for stearoyl-coenzyme A (C18 ). Our findings suggest a novel route to α-amino ketones via the direct condensation of iteratively produced long-chain fatty acids with l-serine by a FAS with a cis-acting AOS off-loading domain.
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Affiliation(s)
- Andrei Ogonkov
- Department of Biology, Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
- Institute of Biology, Leipzig University, Johannisallee 23, 04107, Leipzig, Germany
| | - Cora L Dieterich
- Department of Biology, Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
| | - Roy A Meoded
- Department of Biology, Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
| | - Jörn Piel
- Department of Biology, Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
| | - Amy E Fraley
- Department of Biology, Institute of Microbiology, ETH Zurich, Vladimir-Prelog-Weg 4, 8093, Zurich, Switzerland
| | - Severin Sasso
- Institute of Biology, Leipzig University, Johannisallee 23, 04107, Leipzig, Germany
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3
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Abassi S, Kim HS, Bui QTN, Ki JS. Effects of nitrate on the saxitoxins biosynthesis revealed by sxt genes in the toxic dinoflagellate Alexandrium pacificum (group IV). HARMFUL ALGAE 2023; 127:102473. [PMID: 37544673 DOI: 10.1016/j.hal.2023.102473] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/09/2023] [Accepted: 06/10/2023] [Indexed: 08/08/2023]
Abstract
The dinoflagellate Alexandrium pacificum (group IV) is of particular interest because of its involvement in harmful algal blooms and production of saxitoxin (STX), which causes paralytic shellfish poisoning. The toxicity from STX and its analogues (STXs) is suspected to be affected by nitrogen (N) availability. However, the toxicity-associated behavior and STX-biosynthesis gene responses of the toxic A. pacificum under N fluctuations have not been sufficiently investigated. In the present study, we identified the sxtI gene involved in sxt biosynthesis pathway and evaluated the effects of nitrate (NO3-) on STXs production and the expression of four sxt core genes (sxtA4, sxtG, sxtB, and sxtI). Quantification of total STXs levels in the cultures under different NO3- regimes showed that NO3- concentration influenced STXs production. In addition, the proportion and concentration of STXs varied depending on the NO3- concentration. Core sxt transcript abundance was also influenced by available NO3- in a time-dependent manner. Expressional levels and patterns of sxtI were correlated with those of sxtA and sxtB. The relationship between the toxins and sxt responses in A. pacificum under various NO3- regimes suggests the direct involvement of N in the STXs biosynthesis pathway. Understanding this link would provide a tool to understand the toxin dynamics of dinoflagellates following N shifts in marine environments.
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Affiliation(s)
- Sofia Abassi
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea
| | - Han-Sol Kim
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea
| | - Quynh Thi Nhu Bui
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea
| | - Jang-Seu Ki
- Department of Biotechnology, Sangmyung University, Seoul, 03016, Republic of Korea.
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4
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Ashley B, Baslé A, Sajjad M, el Ashram A, Kelis P, Marles-Wright J, Campopiano DJ. Versatile Chemo-Biocatalytic Cascade Driven by a Thermophilic and Irreversible C-C Bond-Forming α-Oxoamine Synthase. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2023; 11:7997-8002. [PMID: 37266354 PMCID: PMC10230504 DOI: 10.1021/acssuschemeng.3c00243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/24/2023] [Indexed: 06/03/2023]
Abstract
We report a chemo-biocatalytic cascade for the synthesis of substituted pyrroles, driven by the action of an irreversible, thermostable, pyridoxal 5'-phosphate (PLP)-dependent, C-C bond-forming biocatalyst (ThAOS). The ThAOS catalyzes the Claisen-like condensation between various amino acids and acyl-CoA substrates to generate a range of α-aminoketones. These products are reacted with β-keto esters in an irreversible Knorr pyrrole reaction. The determination of the 1.6 Å resolution crystal structure of the PLP-bound form of ThAOS lays the foundation for future engineering and directed evolution. This report establishes the AOS family as useful and versatile C-C bond-forming biocatalysts.
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Affiliation(s)
- Ben Ashley
- School
of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster
Road, Edinburgh EH9 3FJ, United Kingdom
| | - Arnaud Baslé
- Biosciences
Institute, Faculty of Medical Sciences, Newcastle University, Newcastle
upon Tyne NE2 4HH, United Kingdom
| | - Mariyah Sajjad
- School
of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster
Road, Edinburgh EH9 3FJ, United Kingdom
| | - Ahmed el Ashram
- School
of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster
Road, Edinburgh EH9 3FJ, United Kingdom
| | - Panayiota Kelis
- School
of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster
Road, Edinburgh EH9 3FJ, United Kingdom
| | - Jon Marles-Wright
- Biosciences
Institute, Faculty of Medical Sciences, Newcastle University, Newcastle
upon Tyne NE2 4HH, United Kingdom
| | - Dominic J. Campopiano
- School
of Chemistry, University of Edinburgh, Joseph Black Building, David Brewster
Road, Edinburgh EH9 3FJ, United Kingdom
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5
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Lao Y, Skiba MA, Chun SW, Narayan ARH, Smith JL. Structural Basis for Control of Methylation Extent in Polyketide Synthase Metal-Dependent C-Methyltransferases. ACS Chem Biol 2022; 17:2088-2098. [PMID: 35594521 PMCID: PMC9462956 DOI: 10.1021/acschembio.2c00085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Installation of methyl groups can significantly improve the binding of small-molecule drugs to protein targets; however, site-selective methylation often presents a significant synthetic challenge. Metal- and S-adenosyl-methionine (SAM)-dependent methyltransferases (MTs) in natural-product biosynthetic pathways are powerful enzymatic tools for selective or chemically challenging C-methylation reactions. Each of these MTs selectively catalyzes one or two methyl transfer reactions. Crystal structures and biochemical assays of the Mn2+-dependent monomethyltransferase from the saxitoxin biosynthetic pathway (SxtA MT) revealed the structural basis for control of methylation extent. The SxtA monomethyltransferase was converted to a dimethyltransferase by modification of the metal binding site, addition of an active site base, and an amino acid substitution to provide space in the substrate pocket for two methyl substituents. A reciprocal change converted a related dimethyltransferase into a monomethyltransferase, supporting our hypothesis that steric hindrance can prevent a second methylation event. A novel understanding of MTs will accelerate the development of MT-based catalysts and MT engineering for use in small-molecule synthesis.
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Affiliation(s)
- Yongtong Lao
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Meredith A Skiba
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Stephanie W Chun
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Alison R H Narayan
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Janet L Smith
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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6
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Huang ZY, Yang H, Jiang ZY, Zhou L, Li QH, Zhao ZG. In(OTf)3 catalyzed regioselective acyloin rearrangement of 1-acyl-1-indanols. Tetrahedron Lett 2022. [DOI: 10.1016/j.tetlet.2022.153987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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7
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Radka CD, Miller DJ, Frank MW, Rock CO. Biochemical characterization of the first step in sulfonolipid biosynthesis in Alistipes finegoldii. J Biol Chem 2022; 298:102195. [PMID: 35760102 PMCID: PMC9304779 DOI: 10.1016/j.jbc.2022.102195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/16/2022] [Accepted: 06/21/2022] [Indexed: 12/01/2022] Open
Abstract
Sulfonolipids are unusual lipids found in the outer membranes of Gram-negative bacteria in the phylum Bacteroidetes. Sulfonolipid and its deacylated derivative, capnine, are sulfur analogs of ceramide-1-phosphate and sphingosine-1-phosphate, respectively; thus, sulfonolipid biosynthesis is postulated to be similar to the sphingolipid biosynthetic pathway. Here, we identify the first enzyme in sulfonolipid synthesis in Alistipes finegoldii, an anaerobic gut commensal bacterium, as the product of the alfi_1224 gene, cysteate acyl-acyl carrier protein (ACP) transferase (SulA). We show SulA catalyzes the condensation of acyl-ACP and cysteate (3-sulfo-alanine) to form 3-ketocapnine. Acyl-CoA is a poor substrate. We show SulA has a bound pyridoxal phosphate (PLP) cofactor that undergoes a spectral redshift in the presence of cysteate, consistent with the transition of the lysine-aldimine complex to a substrate-aldimine complex. Furthermore, the SulA crystal structure shows the same prototypical fold found in bacterial serine palmitoyltransferases (Spt), enveloping the PLP cofactor bound to Lys251. We observed the SulA and Spt active sites are identical except for Lys281 in SulA, which is an alanine in Spt. Additionally, SulA(K281A) is catalytically inactive, but binds cysteate and forms the external aldimine normally, highlighting the structural role of the Lys281 side chain in walling off the active site from bulk solvent. Finally, the electropositive groove on the protein surface adjacent to the active site entrance provides a landing pad for the electronegative acyl-ACP surface. Taken together, these data identify the substrates, products, and mechanism of SulA, the PLP-dependent condensing enzyme that catalyzes the first step in sulfonolipid synthesis in a gut commensal bacterium.
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Affiliation(s)
- Christopher D Radka
- Departments of, Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, 38015, USA.
| | - Darcie J Miller
- Departments of, Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee, 38015, USA
| | - Matthew W Frank
- Departments of, Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, 38015, USA
| | - Charles O Rock
- Departments of, Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee, 38015, USA
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8
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Colas K, V. D. dos Santos AC, Kohlhepp SV, Mendoza A. Direct Addition of Grignard Reagents to Aliphatic Carboxylic Acids Enabled by Bulky
turbo
‐Organomagnesium Anilides. Chemistry 2022; 28:e202104053. [PMID: 35084063 PMCID: PMC9306512 DOI: 10.1002/chem.202104053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Indexed: 12/22/2022]
Abstract
The synthesis of ketones through addition of organometallic reagents to aliphatic carboxylic acids is a straightforward strategy that is limited to organolithium reagents. More desirable Grignard reagents can be activated and controlled with a bulky aniline‐derived turbo‐Hauser base. This operationally simple procedure allows the straightforward preparation of a variety of aliphatic and perfluoroalkyl ketones alike from functionalized alkyl, aryl and heteroaryl Grignard reagents.
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Affiliation(s)
- Kilian Colas
- Dept. of Organic Chemistry Stockholm University Arrhenius Laboratory 106 91 Stockholm Sweden
| | | | - Stefanie V. Kohlhepp
- Dept. of Organic Chemistry Stockholm University Arrhenius Laboratory 106 91 Stockholm Sweden
| | - Abraham Mendoza
- Dept. of Organic Chemistry Stockholm University Arrhenius Laboratory 106 91 Stockholm Sweden
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9
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Cheng N, Cui SQ, Ma QQ, Wei ZL, Liao WW. α-Iminol Rearrangement Triggered by Pd-Catalyzed C-H Addition to Nitriles Sequences: Synthesis of Functionalized α-Amino Cyclopentanones. Org Lett 2021; 23:1021-1025. [PMID: 33496596 DOI: 10.1021/acs.orglett.0c04214] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A α-iminol rearrangement triggered by Pd-catalyzed C-H addition of electronic-rich heteroarenes to cyclobutanone-derived O-acyl cyanohydrins was described, which provided a practical and efficient protocol for the preparation of functionalized α-amino cyclopentanones in an atom- and step-economic fashion. In addition, further synthetic transformations of products have also been demonstrated.
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Affiliation(s)
- Na Cheng
- Department of Organic Chemistry, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P.R. China
| | - Shu-Qiang Cui
- Department of Organic Chemistry, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P.R. China
| | - Qian-Qian Ma
- Department of Organic Chemistry, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P.R. China
| | - Zhong-Lin Wei
- Department of Organic Chemistry, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P.R. China
| | - Wei-Wei Liao
- Department of Organic Chemistry, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P.R. China.,State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, P.R. China
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10
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Zhou T, Gao D, Li JX, Xu MJ, Xu J. Identification of an α-Oxoamine Synthase and a One-Pot Two-Step Enzymatic Synthesis of α-Amino Ketones. Org Lett 2020; 23:37-41. [PMID: 33284636 DOI: 10.1021/acs.orglett.0c03600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alb29, an α-oxoamine synthase involved in albogrisin biosynthesis in Streptomyces albogriseolus MGR072, was characterized and responsible for the incorporation of l-glutamate to acyl-coenzyme A substrates. Combined with Alb29 and Mgr36 (an acyl-coenzyme A ligase), a one-pot enzymatic system was established to synthesize seven α-amino ketones. When these α-amino ketones were fed into the alb29 knockout strain Δalb29, respectively, the albogrisin analogs with different side chains were observed.
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Affiliation(s)
- Ting Zhou
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.,Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Du Gao
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China.,Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Jia-Xin Li
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Min-Juan Xu
- Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Centre for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
| | - Jun Xu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, P. R. China
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11
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Zetzsche LE, Narayan ARH. Broadening the scope of biocatalytic C-C bond formation. Nat Rev Chem 2020; 4:334-346. [PMID: 34430708 PMCID: PMC8382263 DOI: 10.1038/s41570-020-0191-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/28/2020] [Indexed: 12/18/2022]
Abstract
The impeccable control over chemo-, site-, and stereoselectivity possible in enzymatic reactions has led to a surge in the development of new biocatalytic methods. Despite carbon-carbon (C-C) bonds providing the central framework for organic molecules, development of biocatalytic methods for their formation has been largely confined to the use of a select few lyases over the last several decades, limiting the types of C-C bond-forming transformations possible through biocatalytic methods. This Review provides an update on the suite of enzymes available for highly selective biocatalytic C-C bond formation. Examples will be discussed in reference to the (1) native activity of enzymes, (2) alteration of activity through protein or substrate engineering for broader applicability, and (3) utility of the biocatalyst for abiotic synthesis.
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Affiliation(s)
- Lara E. Zetzsche
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alison R. H. Narayan
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109, USA
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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12
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Dai L, Li X, Zeng Z, Dong S, Zhou Y, Liu X, Feng X. Catalytic Asymmetric Acyloin Rearrangements of α-Ketols, α-Hydroxy Aldehydes, and α-Iminols by N, N'-Dioxide-Metal Complexes. Org Lett 2020; 22:5041-5045. [PMID: 32610927 DOI: 10.1021/acs.orglett.0c01626] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A highly enantioselective acyloin rearrangement of cyclic α-ketols has been developed with a chiral Al(III)-N,N'-dioxide complex as catalyst. This strategy provided an array of optically active 2-acyl-2-hydroxy cyclohexanones in moderate to good yields with high enantioselectivities. The asymmetric isomerizations of acyclic α-hydroxy aldehydes and α-iminols were achieved as well under modified conditions, affording the corresponding chiral α-hydroxy ketones and α-amino ketones in moderate results. Moreover, further transformations of product to enantioenriched diols were carried out.
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Affiliation(s)
- Li Dai
- Key Laboratory of Green Chemistry &Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xiangqiang Li
- Key Laboratory of Green Chemistry &Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Zi Zeng
- Key Laboratory of Green Chemistry &Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Shunxi Dong
- Key Laboratory of Green Chemistry &Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Yuqiao Zhou
- Key Laboratory of Green Chemistry &Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xiaohua Liu
- Key Laboratory of Green Chemistry &Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xiaoming Feng
- Key Laboratory of Green Chemistry &Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China
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13
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Chen Y, Liu Y, Li Z, Dong S, Liu X, Feng X. Tandem Insertion–[1,3]‐Rearrangement: Highly Enantioselective Construction of α‐Aminoketones. Angew Chem Int Ed Engl 2020; 59:8052-8056. [DOI: 10.1002/anie.201914645] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/28/2020] [Indexed: 12/17/2022]
Affiliation(s)
- Yushuang Chen
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Yun Liu
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Zhaojing Li
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Shunxi Dong
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Xiaohua Liu
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Xiaoming Feng
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
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14
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Chen Y, Liu Y, Li Z, Dong S, Liu X, Feng X. Tandem Insertion–[1,3]‐Rearrangement: Highly Enantioselective Construction of α‐Aminoketones. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201914645] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yushuang Chen
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Yun Liu
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Zhaojing Li
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Shunxi Dong
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Xiaohua Liu
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
| | - Xiaoming Feng
- Key Laboratory of Green Chemistry & TechnologyMinistry of EducationCollege of ChemistrySichuan University Chengdu 610064 China
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15
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D'Agostino PM, Al-Sinawi B, Mazmouz R, Muenchhoff J, Neilan BA, Moffitt MC. Identification of promoter elements in the Dolichospermum circinale AWQC131C saxitoxin gene cluster and the experimental analysis of their use for heterologous expression. BMC Microbiol 2020; 20:35. [PMID: 32070286 PMCID: PMC7027233 DOI: 10.1186/s12866-020-1720-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/03/2020] [Indexed: 01/06/2023] Open
Abstract
Background Dolichospermum circinale is a filamentous bloom-forming cyanobacterium responsible for biosynthesis of the paralytic shellfish toxins (PST), including saxitoxin. PSTs are neurotoxins and in their purified form are important analytical standards for monitoring the quality of water and seafood and biomedical research tools for studying neuronal sodium channels. More recently, PSTs have been recognised for their utility as local anaesthetics. Characterisation of the transcriptional elements within the saxitoxin (sxt) biosynthetic gene cluster (BGC) is a first step towards accessing these molecules for biotechnology. Results In D. circinale AWQC131C the sxt BGC is transcribed from two bidirectional promoter regions encoding five individual promoters. These promoters were identified experimentally using 5′ RACE and their activity assessed via coupling to a lux reporter system in E. coli and Synechocystis sp. PCC 6803. Transcription of the predicted drug/metabolite transporter (DMT) encoded by sxtPER was found to initiate from two promoters, PsxtPER1 and PsxtPER2. In E. coli, strong expression of lux from PsxtP, PsxtD and PsxtPER1 was observed while expression from Porf24 and PsxtPER2 was remarkably weaker. In contrast, heterologous expression in Synechocystis sp. PCC 6803 showed that expression of lux from PsxtP, PsxtPER1, and Porf24 promoters was statistically higher compared to the non-promoter control, while PsxtD showed poor activity under the described conditions. Conclusions Both of the heterologous hosts investigated in this study exhibited high expression levels from three of the five sxt promoters. These results indicate that the majority of the native sxt promoters appear active in different heterologous hosts, simplifying initial cloning efforts. Therefore, heterologous expression of the sxt BGC in either E. coli or Synechocystis could be a viable first option for producing PSTs for industrial or biomedical purposes.
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Affiliation(s)
- Paul M D'Agostino
- School of Science, Western Sydney University, Sydney, NSW, Australia.,School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Biosystems Chemistry, Department of Chemistry, Technische Universität München, Garching, Germany.,Technical Biochemistry, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, Germany
| | - Bakir Al-Sinawi
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Rabia Mazmouz
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Julia Muenchhoff
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia.,Centre for Healthy Brain Ageing, School of Psychiatry, University of New South Wales, Sydney, Australia
| | - Brett A Neilan
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia. .,School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia.
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