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Dou C, Long Z, Li S, Zhou D, Jin Y, Zhang L, Zhang X, Zheng Y, Li L, Zhu X, Liu Z, He S, Yan W, Yang L, Xiong J, Fu X, Qi S, Ren H, Chen S, Dai L, Wang B, Cheng W. Crystal structure and catalytic mechanism of the MbnBC holoenzyme required for methanobactin biosynthesis. Cell Res 2022; 32:302-314. [PMID: 35110668 PMCID: PMC8888699 DOI: 10.1038/s41422-022-00620-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/12/2022] [Indexed: 02/08/2023] Open
Abstract
Methanobactins (Mbns) are a family of copper-binding peptides involved in copper uptake by methanotrophs, and are potential therapeutic agents for treating diseases characterized by disordered copper accumulation. Mbns are produced via modification of MbnA precursor peptides at cysteine residues catalyzed by the core biosynthetic machinery containing MbnB, an iron-dependent enzyme, and MbnC. However, mechanistic details underlying the catalysis of the MbnBC holoenzyme remain unclear. Here, we present crystal structures of MbnABC complexes from two distinct species, revealing that the leader peptide of the substrate MbnA binds MbnC for recruitment of the MbnBC holoenzyme, while the core peptide of MbnA resides in the catalytic cavity created by the MbnB-MbnC interaction which harbors a unique tri-iron cluster. Ligation of the substrate sulfhydryl group to the tri-iron center achieves a dioxygen-dependent reaction for oxazolone-thioamide installation. Structural analysis of the MbnABC complexes together with functional investigation of MbnB variants identified a conserved catalytic aspartate residue as a general base required for MbnBC-mediated MbnA modification. Together, our study reveals the similar architecture and function of MbnBC complexes from different species, demonstrating an evolutionarily conserved catalytic mechanism of the MbnBC holoenzymes.
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Affiliation(s)
- Chao Dou
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Zhaolin Long
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Shoujie Li
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Dan Zhou
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Ying Jin
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Li Zhang
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Xuan Zhang
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, China
| | - Yanhui Zheng
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Lin Li
- National Institute of Biological Sciences, NIBS, Beijing, China
| | - Xiaofeng Zhu
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China.,College of Life Science, Sichuan University, Chengdu, Sichuan, China
| | - Zheng Liu
- Beijing National Laboratory for Molecular Sciences (BNLMS), Beijing Key Laboratory for Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Siyu He
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Weizhu Yan
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Lulu Yang
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Jie Xiong
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Xianghui Fu
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Shiqian Qi
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Haiyan Ren
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - She Chen
- National Institute of Biological Sciences, NIBS, Beijing, China
| | - Lunzhi Dai
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Binju Wang
- State Key Laboratory of Structural Chemistry of Solid Surface and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian, China
| | - Wei Cheng
- Division of Respiratory and Critical Care Medicine, Respiratory Infection and Intervention Laboratory of Frontiers Science Center for Disease-related Molecular Network, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
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Gong B, Bai E, Feng X, Yi L, Wang Y, Chen X, Zhu X, Duan Y, Huang Y. Characterization of Chalkophomycin, a Copper(II) Metallophore with an Unprecedented Molecular Architecture. J Am Chem Soc 2021; 143:20579-20584. [PMID: 34851100 DOI: 10.1021/jacs.1c09311] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Metals play essential roles in life by coordination with small molecules, proteins, and nucleic acids. Although the coordination of copper ions in many proteins and methanobactins is known, the coordination chemistry of Cu(II) in natural products and their biological functions remain underexplored. Herein, we report the discovery of a Cu(II)-binding natural product, chalkophomycin (CHM, 1), from Streptomyces sp. CB00271, featuring an asymmetric square-coordination system of a bidentate diazeniumdiolate and a conjugated 1H-pyrrole 1-oxide-oxazoline. The structure of 1 may inspire the synthesis of Cu(II) chelators against neurodegenerative diseases or Cu(II)-based antitumor therapeutics.
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Affiliation(s)
- Bang Gong
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China
| | - Enhe Bai
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China
| | - Xueqiong Feng
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China
| | - Liwei Yi
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China
| | - Yeji Wang
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China
| | - Xin Chen
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China
| | - Xiangcheng Zhu
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China.,Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, Changsha, 410011, Hunan, China.,National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, 410011, Changsha, Hunan, China
| | - Yanwen Duan
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China.,Hunan Engineering Research Center of Combinatorial Biosynthesis and Natural Product Drug Discovery, Changsha, 410011, Hunan, China.,National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, 410011, Changsha, Hunan, China
| | - Yong Huang
- Xiangya International Academy of Translational Medicine at Central South University, Changsha, 410013, Hunan, China.,National Engineering Research Center of Combinatorial Biosynthesis for Drug Discovery, 410011, Changsha, Hunan, China
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Abstract
Methanobactins (Mbns) are ribosomally produced, post-translationally modified peptide (RiPP) natural products that bind copper with high affinity using nitrogen-containing heterocycles and thioamide groups. In some methanotrophic bacteria, Mbns are secreted under conditions of copper starvation and then re-internalized as a copper source for the enzyme particulate methane monooxygenase (pMMO). Genome mining studies have led to the identification and classification of operons encoding the Mbn precursor peptide (MbnA) as well as a number of putative transport, regulatory, and biosynthetic proteins. These Mbn operons are present in non-methanotrophic bacteria as well, suggesting a broader role in and perhaps beyond copper acquisition. Genetic and biochemical studies indicate that specific operon-encoded proteins are involved in Mbn transport and provide insight into copper-responsive gene regulation in methanotrophs. Mbn biosynthesis is not yet understood, but combined analysis of Mbn structures, MbnA sequences, and operon content represents a powerful approach to elucidating the roles of specific biosynthetic enzymes. Future work will likely lead to the discovery of unique pathways for natural product biosynthesis and new mechanisms of microbial metal homeostasis.
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Affiliation(s)
- Laura M K Dassama
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
| | - Grace E Kenney
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA.
| | - Amy C Rosenzweig
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA. and Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
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An Aminotransferase Is Responsible for the Deamination of the N-Terminal Leucine and Required for Formation of Oxazolone Ring A in Methanobactin of Methylosinus trichosporium OB3b. Appl Environ Microbiol 2016; 83:AEM.02619-16. [PMID: 27795312 DOI: 10.1128/aem.02619-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 10/14/2016] [Indexed: 01/27/2023] Open
Abstract
Gene expression in methanotrophs has been shown to be affected by the availability of a variety of metals, most notably copper-regulating expression of alternative forms of methane monooxygenase. A copper-binding compound, or chalkophore, called methanobactin plays a key role in copper uptake in methanotrophs. Methanobactin is a ribosomally synthesized and posttranslationally modified peptide (RiPP) with two heterocyclic rings with an associated thioamide for each ring, formed from X-Cys dipeptide sequences that bind copper. The gene coding for the precursor polypeptide of methanobactin, mbnA, is part of a gene cluster, but the role of other genes in methanobactin biosynthesis is unclear. To begin to elucidate the function of these genes, we constructed an unmarked deletion of mbnABCMN in Methylosinus trichosporium OB3b and then homologously expressed mbnABCM using a broad-host-range cloning vector to determine the function of mbnN, annotated as coding for an aminotransferase. Methanobactin produced by this strain was found to be substantially different from wild-type methanobactin in that the C-terminal methionine was missing and only one of the two oxazolone rings was formed. Rather, in place of the N-terminal 3-methylbutanoyl-oxazolone-thioamide group, a leucine and a thioamide-containing glycine (Gly-Ψ) were found, indicating that MbnN is used for deamination of the N-terminal leucine of methanobactin and that this posttranslational modification is critical for closure of the N-terminal oxazolone ring in M. trichosporium OB3b. These studies provide new insights into methanobactin biosynthesis and also provide a platform for understanding the function of other genes in the methanobactin gene cluster. IMPORTANCE Methanotrophs, microbes that play a critical role in the carbon cycle, are influenced by copper, with gene expression and enzyme activity changing as copper levels change. Methanotrophs produce a copper-binding compound, or chalkophore, called methanobactin for copper uptake, and methanobactin plays a key role in controlling methanotrophic activity. Methanobactin has also been shown to be effective in the treatment of Wilson disease, an autosomal recessive disorder where the human body cannot correctly assimilate copper. It is important to characterize the methanobactin biosynthesis pathway to understand how methanotrophs respond to their environment as well as to optimize the use of methanobactin for the treatment of copper-related diseases such as Wilson disease. Here we show that mbnN, encoding an aminotransferase, is involved in the deamination of the N-terminal leucine and necessary for the formation of one but not both of the heterocyclic rings in methanobactin that are responsible for copper binding.
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