1
|
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.
Collapse
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
| |
Collapse
|
2
|
Atanasoff-Kardjalieff AK, Lünne F, Kalinina S, Strauss J, Humpf HU, Studt L. Biosynthesis of Fusapyrone Depends on the H3K9 Methyltransferase, FmKmt1, in Fusarium mangiferae. FRONTIERS IN FUNGAL BIOLOGY 2021; 2:671796. [PMID: 37744112 PMCID: PMC10512364 DOI: 10.3389/ffunb.2021.671796] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/09/2021] [Indexed: 09/26/2023]
Abstract
The phytopathogenic fungus Fusarium mangiferae belongs to the Fusarium fujikuroi species complex (FFSC). Members of this group cause a wide spectrum of devastating diseases on diverse agricultural crops. F. mangiferae is the causal agent of the mango malformation disease (MMD) and as such detrimental for agriculture in the southern hemisphere. During plant infection, the fungus produces a plethora of bioactive secondary metabolites (SMs), which most often lead to severe adverse defects on plants health. Changes in chromatin structure achieved by posttranslational modifications (PTM) of histones play a key role in regulation of fungal SM biosynthesis. Posttranslational tri-methylation of histone 3 lysine 9 (H3K9me3) is considered a hallmark of heterochromatin and established by the SET-domain protein Kmt1. Here, we show that FmKmt1 is involved in H3K9me3 in F. mangiferae. Loss of FmKmt1 only slightly though significantly affected fungal hyphal growth and stress response and is required for wild type-like conidiation. While FmKmt1 is largely dispensable for the biosynthesis of most known SMs, removal of FmKMT1 resulted in an almost complete loss of fusapyrone and deoxyfusapyrone, γ-pyrones previously only known from Fusarium semitectum. Here, we identified the polyketide synthase (PKS) FmPKS40 to be involved in fusapyrone biosynthesis, delineate putative cluster borders by co-expression studies and provide insights into its regulation.
Collapse
Affiliation(s)
- Anna K. Atanasoff-Kardjalieff
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna (BOKU), Tulln an der Donau, Austria
| | - Friederike Lünne
- Institute of Food Chemistry, Westfälische Wilhelms-Universität, Münster, Germany
| | - Svetlana Kalinina
- Institute of Food Chemistry, Westfälische Wilhelms-Universität, Münster, Germany
| | - Joseph Strauss
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna (BOKU), Tulln an der Donau, Austria
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, Westfälische Wilhelms-Universität, Münster, Germany
| | - Lena Studt
- Department of Applied Genetics and Cell Biology, Institute of Microbial Genetics, University of Natural Resources and Life Sciences, Vienna (BOKU), Tulln an der Donau, Austria
| |
Collapse
|
3
|
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.
Collapse
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
Collapse
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
| |
Collapse
|
4
|
Morris JS, Yu L, Facchini PJ. A single residue determines substrate preference in benzylisoquinoline alkaloid N-methyltransferases. PHYTOCHEMISTRY 2020; 170:112193. [PMID: 31765874 DOI: 10.1016/j.phytochem.2019.112193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 06/10/2023]
Abstract
N-methylation is a recurring feature in the biosynthesis of many plant specialized metabolites, including alkaloids. A crucial step in the conserved central pathway that provides intermediates for the biosynthesis of benzylisoquinoline alkaloids (BIAs) involves conversion of the secondary amine (S)-coclaurine into the tertiary amine (S)-N-methylcoclaurine by coclaurine N-methyltransferase (CNMT). Subsequent enzymatic steps yield the core intermediate (S)-reticuline, from which various branch pathways for the biosynthesis of major BIAs such as morphine, noscapine and sanguinarine diverge. An additional N-methylation yielding quaternary BIAs is catalyzed by reticuline N-methyltransferase (RNMT), such as in the branch pathway leading to the taxonomically widespread and ecologically significant alkaloid magnoflorine. Despite their functional differences, analysis of primary sequence information has been unable to accurately distinguish between CNMT-like and RNMT-like enzymes, necessitating laborious in vitro screening. Furthermore, despite a recent emphasis on structural characterization of BIA NMTs, the features and mechanisms underlying the CNMT-RNMT functional dichotomy were unknown. We report the identification of structural variants tightly correlated with function in known BIA NMTs and show through reciprocal mutagenesis that a single residue acts as a switch between CNMT- and RNMT-like functions. We use yeast in vivo screening to show that this discovery allows for accurate prediction of activity strictly from primary sequence information and, on this basis, improve the annotation of previously reported putative BIA NMTs. Our results highlight the unusually short mutational distance separating ancestral CNMT-like enzymes from more evolutionarily advanced RNMT-like enzymes, and thus help explain the widespread yet sporadic occurrence of quaternary BIAs in plants. While this is the first report of structural variants controlling mono-versus di-methylation activity among plant NMT enzymes, comparison with bacterial MT enzymes also suggests possible convergent evolution.
Collapse
Affiliation(s)
- Jeremy S Morris
- University of Calgary, Department of Biological Sciences, Calgary, Alberta, T2N 1N4, Canada
| | - Lisa Yu
- University of Calgary, Department of Biological Sciences, Calgary, Alberta, T2N 1N4, Canada
| | - Peter J Facchini
- University of Calgary, Department of Biological Sciences, Calgary, Alberta, T2N 1N4, Canada.
| |
Collapse
|
5
|
Abstract
A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as vlasoulamine A from Vladimiria souliei.
Collapse
|