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Zou N, Zhou D, Chen Y, Lin P, Chen Y, Wang W, Xie J, Wang M. A Novel Antifungal Actinomycete Streptomyces sp. Strain H3-2 Effectively Controls Banana Fusarium Wilt. Front Microbiol 2021; 12:706647. [PMID: 34497593 PMCID: PMC8419470 DOI: 10.3389/fmicb.2021.706647] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 07/15/2021] [Indexed: 11/13/2022] Open
Abstract
Banana Fusarium wilt disease caused by Fusarium oxyspoum f. sp. cubense (Foc) seriously threatens the banana industry. Foc tropical race 4 (Foc TR4) can infect almost all banana cultivars. Compared with traditional physical and chemical practices, biocontrol strategy using beneficial microbes is considered as an environmentally sound option to manage fungal disease. In this study, a strain, H3-2, isolated from a non-infected banana orchard, exhibited high antifungal activity against Foc TR4. According to its morphological, physiological, and biochemical characteristics, the strain H3-2 was identified as Streptomyces sp. and convinced by the polymorphic phylogenic analysis of 16S rRNA sequences. Extracts of the strain H3-2 suppressed the growth and spore germination of Foc TR4 in vitro by destroying cell membrane integrity and mycelial ultrastructure. Notably, the strain and its extracts showed broad-spectrum antifungal activity against the selected seven fungal phytopathogens. Fourteen chemical compounds in the extracts were identified by gas chromatography–mass spectrometer (GC-MS), primarily phenolic compounds. Additional pot inoculation experiment demonstrated that the fermentation broth of the strain H3-2 promoted the growth of banana seedlings by efficiently inhibiting the spread of banana Fusarium wilt disease. This study demonstrated the potential application of the novel Streptomyces sp. H3-2 for the management of banana Fusarium wilt.
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Affiliation(s)
- Niexia Zou
- Institute of Horticultural Science and Engineering, Huaqiao University, Xiamen, China.,Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Dengbo Zhou
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Yinglong Chen
- School of Agriculture and Environment, The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Ping Lin
- Institute of Horticultural Science and Engineering, Huaqiao University, Xiamen, China
| | - Yufeng Chen
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Wei Wang
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Jianghui Xie
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Mingyuan Wang
- Institute of Horticultural Science and Engineering, Huaqiao University, Xiamen, China
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Park SH, Park J, Lee SJ, Yang WS, Park S, Kim K, Park ZY, Song HK. A host dTMP-bound structure of T4 phage dCMP hydroxymethylase mutant using an X-ray free electron laser. Sci Rep 2019; 9:16316. [PMID: 31705139 PMCID: PMC6841964 DOI: 10.1038/s41598-019-52825-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 10/22/2019] [Indexed: 01/21/2023] Open
Abstract
The hydroxymethylation of cytosine bases plays a vital role in the phage DNA protection system inside the host Escherichia coli. This modification is known to be catalyzed by the dCMP hydroxymethylase from bacteriophage T4 (T4dCH); structural information on the complexes with the substrate, dCMP and the co-factor, tetrahydrofolate is currently available. However, the detailed mechanism has not been understood clearly owing to a lack of structure in the complex with a reaction intermediate. We have applied the X-ray free electron laser (XFEL) technique to determine a high-resolution structure of a T4dCH D179N active site mutant. The XFEL structure was determined at room temperature and exhibited several unique features in comparison with previously determined structures. Unexpectedly, we observed a bulky electron density at the active site of the mutant that originated from the physiological host (i.e., E. coli). Mass-spectrometric analysis and a cautious interpretation of an electron density map indicated that it was a dTMP molecule. The bound dTMP mimicked the methylene intermediate from dCMP to 5′-hydroxymethy-dCMP, and a critical water molecule for the final hydroxylation was convincingly identified. Therefore, this study provides information that contributes to the understanding of hydroxymethylation.
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Affiliation(s)
- Si Hoon Park
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, South Korea
| | - Jaehyun Park
- PAL-XFEL, Pohang Accelerator Laboratory, POSTECH, Pohang, Gyeongbuk, 37673, South Korea
| | - Sang Jae Lee
- PAL-XFEL, Pohang Accelerator Laboratory, POSTECH, Pohang, Gyeongbuk, 37673, South Korea
| | - Woo Seok Yang
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, South Korea
| | - Sehan Park
- PAL-XFEL, Pohang Accelerator Laboratory, POSTECH, Pohang, Gyeongbuk, 37673, South Korea
| | - Kyungdo Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Zee-Yong Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, 61005, South Korea
| | - Hyun Kyu Song
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, South Korea.
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Park SH, Suh SW, Song HK. A cytosine modification mechanism revealed by the structure of a ternary complex of deoxycytidylate hydroxymethylase from bacteriophage T4 with its cofactor and substrate. IUCRJ 2019; 6:206-217. [PMID: 30867918 PMCID: PMC6400193 DOI: 10.1107/s2052252518018274] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 12/24/2018] [Indexed: 06/09/2023]
Abstract
To protect viral DNA against the host bacterial restriction system, bacterio-phages utilize a special modification system - hydroxymethylation - in which dCMP hydroxymethylase (dCH) converts dCMP to 5-hydroxymethyl-dCMP (5hm-dCMP) using N5,N10-methylenetetrahydrofolate as a cofactor. Despite shared similarity with thymidylate synthase (TS), dCH catalyzes hydroxylation through an exocyclic methylene intermediate during the last step, which is different from the hydride transfer that occurs with TS. In contrast to the extensively studied TS, the hydroxymethylation mechanism of a cytosine base is not well understood due to the lack of a ternary complex structure of dCH in the presence of both its substrate and cofactor. This paper reports the crystal structure of the ternary complex of dCH from bacteriophage T4 (T4dCH) with dCMP and tetrahydrofolate at 1.9 Å resolution. The authors found key residues of T4dCH for accommodating the cofactor without a C-terminal tail, an optimized network of ordered water molecules and a hydrophobic gating mechanism for cofactor regulation. In combination with biochemical data on structure-based mutants, key residues within T4dCH and a substrate water molecule for hydroxymethylation were identified. Based on these results, a complete enzyme mechanism of dCH and signature residues that can identify dCH enzymes within the TS family have been proposed. These findings provide a fundamental basis for understanding the pyrimidine modification system.
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Affiliation(s)
- Si Hoon Park
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Se Won Suh
- Departments of Chemistry, Seoul National University, Kwanak-ro 1, Kwanak-gu, Seoul 08826, Republic of Korea
| | - Hyun Kyu Song
- Department of Life Sciences, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
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Myllykallio H, Sournia P, Heliou A, Liebl U. Unique Features and Anti-microbial Targeting of Folate- and Flavin-Dependent Methyltransferases Required for Accurate Maintenance of Genetic Information. Front Microbiol 2018; 9:918. [PMID: 29867829 PMCID: PMC5954106 DOI: 10.3389/fmicb.2018.00918] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/20/2018] [Indexed: 12/14/2022] Open
Abstract
Comparative genome analyses have led to the discovery and characterization of novel flavin- and folate-dependent methyltransferases that mainly function in DNA precursor synthesis and post-transcriptional RNA modification by forming (ribo) thymidylate and its derivatives. Here we discuss the recent literature on the novel mechanistic features of these enzymes sometimes referred to as “uracil methyltransferases,” albeit we prefer to refer to them as (ribo) thymidylate synthases. These enzyme families attest to the convergent evolution of nucleic acid methylation. Special focus is given to describing the unique characteristics of these flavin- and folate-dependent enzymes that have emerged as new models for studying the non-canonical roles of reduced flavin co-factors (FADH2) in relaying carbon atoms between enzyme substrates. This ancient enzymatic methylation mechanism with a very wide phylogenetic distribution may be more commonly used for biological methylation reactions than previously anticipated. This notion is exemplified by the recent discovery of additional substrates for these enzymes. Moreover, similar reaction mechanisms can be reversed by demethylases, which remove methyl groups e.g., from human histones. Future work is now required to address whether the use of different methyl donors facilitates the regulation of distinct methylation reactions in the cell. It will also be of great interest to address whether the low activity flavin-dependent thymidylate synthases ThyX represent ancestral enzymes that were eventually replaced by the more active thymidylate synthases of the ThyA family to facilitate the maintenance of larger genomes in fast-growing microbes. Moreover, we discuss the recent efforts from several laboratories to identify selective anti-microbial compounds that target flavin-dependent thymidylate synthase ThyX. Altogether we underline how the discovery of the alternative flavoproteins required for methylation of DNA and/or RNA nucleotides, in addition to providing novel targets for antibiotics, has provided new insight into microbial physiology and virulence.
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Affiliation(s)
- Hannu Myllykallio
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Palaiseau, France
| | - Pierre Sournia
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Palaiseau, France
| | - Alice Heliou
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Palaiseau, France.,Laboratoire d'Informatique de l'École Polytechnique, Ecole Polytechnique, Centre National de la Recherche Scientifique, Université Paris-Saclay, Palaiseau, France
| | - Ursula Liebl
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, Université Paris-Saclay, Palaiseau, France
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Niu G, Zheng J, Tan H. Biosynthesis and combinatorial biosynthesis of antifungal nucleoside antibiotics. SCIENCE CHINA-LIFE SCIENCES 2017; 60:939-947. [DOI: 10.1007/s11427-017-9116-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 05/08/2017] [Indexed: 11/28/2022]
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