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Brahma R, Raghuraman H. Characterization of a novel MgtE homolog and its structural dynamics in membrane mimetics. Biophys J 2024; 123:1968-1983. [PMID: 38042987 PMCID: PMC11309985 DOI: 10.1016/j.bpj.2023.11.3402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/03/2023] [Accepted: 11/30/2023] [Indexed: 12/04/2023] Open
Abstract
Magnesium (Mg2+) is the most abundant divalent cation in the cell and is critical for numerous cellular processes. Despite its importance, the mechanisms of intracellular Mg2+ transport and its regulation are poorly understood. MgtE is the main Mg2+ transport system in almost half of bacterial species and is an ortholog of mammalian SLC41A1 transporters, which are implicated in neurodegenerative diseases and cancer. To date, only MgtE from Thermus thermophilus (MgtETT) has been extensively characterized, mostly in detergent micelles, and gating-related structural dynamics in biologically relevant membranes are scarce. The MgtE homolog from Bacillus firmus (MgtEBF) is unique since it lacks the entire Mg2+-sensing N-domain but has conserved structural motifs in the TM-domain for Mg2+ transport. In this work, we have successfully purified this novel homolog in a stable and functional form, and ColabFold structure prediction analysis suggests a homodimer. Further, microscale thermophoresis experiments show that MgtEBF binds Mg2+ and ATP, similar to MgtETT. Importantly, we show that, despite lacking the N-domain, MgtEBF mediates Mg2+ transport function in the presence of an inwardly directed Mg2+ gradient in reconstituted proteoliposomes. Furthermore, comparison of the organization and dynamics of Trp residues in the TM-domain of MgtEBF in membrane mimetics, in apo- and Mg2+-bound forms, suggests that the cytoplasmic binding of Mg2+ might involve modest gating-related conformational changes at the TM-domain. Overall, our results show that the gating-related structural dynamics (hydration dynamics, conformational heterogeneity) of the full-length MgtEBF is significantly changed in functionally pertinent membrane environment, emphasizing the importance of lipid-protein interactions in MgtE gating mechanisms.
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Affiliation(s)
- Rupasree Brahma
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, India; Homi Bhabha National Institute, Training School Complex, Mumbai, India
| | - H Raghuraman
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, India; Homi Bhabha National Institute, Training School Complex, Mumbai, India.
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2
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Zeinert R, Zhou F, Franco P, Zöller J, Lessen HJ, Aravind L, Langer JD, Sodt AJ, Storz G, Matthies D. Magnesium Transporter MgtA revealed as a Dimeric P-type ATPase. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.28.582502. [PMID: 38464158 PMCID: PMC10925321 DOI: 10.1101/2024.02.28.582502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Magnesium (Mg2+) uptake systems are present in all domains of life given the vital role of this ion. Bacteria acquire Mg2+ via conserved Mg2+ channels and transporters. The transporters are required for growth when Mg2+ is limiting or during bacterial pathogenesis, but, despite their significance, there are no known structures for these transporters. Here we report the first structure of the Mg2+ transporter MgtA solved by single particle cryo-electron microscopy (cryo-EM). Using mild membrane extraction, we obtained high resolution structures of both a homodimeric form (2.9 Å), the first for a P-type ATPase, and a monomeric form (3.6 Å). Each monomer unit of MgtA displays a structural architecture that is similar to other P-type ATPases with a transmembrane domain and two soluble domains. The dimer interface consists of contacts between residues in adjacent soluble nucleotide binding and phosphotransfer regions of the haloacid dehalogenase (HAD) domain. We suggest oligomerization is a conserved structural feature of the diverse family of P-type ATPase transporters. The ATP binding site and conformational dynamics upon nucleotide binding to MgtA were characterized using a combination of cryo-EM, molecular dynamics simulations, hydrogen-deuterium exchange mass spectrometry, and mutagenesis. Our structure also revealed a Mg2+ ion in the transmembrane segments, which, when combined with sequence conservation and mutagenesis studies, allowed us to propose a model for Mg2+ transport across the lipid bilayer. Finally, our work revealed the N-terminal domain structure and cytoplasmic Mg2+ binding sites, which have implications for related P-type ATPases defective in human disease.
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Affiliation(s)
- Rilee Zeinert
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - Fei Zhou
- Unit on Structural Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - Pedro Franco
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Jonathan Zöller
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Henry J. Lessen
- Unit on Membrane Chemical Physics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - L. Aravind
- National Center for Biotechnology Information, National Institutes of Health, Bethesda MD 20892, USA
| | - Julian D. Langer
- Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Alexander J. Sodt
- Unit on Membrane Chemical Physics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
| | - Doreen Matthies
- Unit on Structural Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda MD 20892, USA
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3
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Metaane S, Monteil V, Douché T, Giai Gianetto Q, Matondo M, Maufrais C, Norel F. Loss of CorA, the primary magnesium transporter of Salmonella, is alleviated by MgtA and PhoP-dependent compensatory mechanisms. PLoS One 2023; 18:e0291736. [PMID: 37713445 PMCID: PMC10503707 DOI: 10.1371/journal.pone.0291736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/05/2023] [Indexed: 09/17/2023] Open
Abstract
In many Gram-negative bacteria, the stress sigma factor of RNA polymerase, σS/RpoS, remodels global gene expression to reshape the physiology of stationary phase cells and ensure their survival under non-optimal growth conditions. In the foodborne pathogen Salmonella enterica serovar Typhimurium, σS is also required for biofilm formation and virulence. We have recently shown that a ΔrpoS mutation decreases the magnesium content and expression level of the housekeeping Mg2+-transporter CorA in stationary phase Salmonella. The other two Mg2+-transporters of Salmonella are encoded by the PhoP-activated mgtA and mgtB genes and are expressed under magnesium starvation. The σS control of corA prompted us to evaluate the impact of CorA in stationary phase Salmonella cells, by using global and analytical proteomic analyses and physiological assays. The ΔcorA mutation conferred a competitive disadvantage to exit from stationary phase, and slightly impaired motility, but had no effect on total and free cellular magnesium contents. In contrast to the wild-type strain, the ΔcorA mutant produced MgtA, but not MgtB, in the presence of high extracellular magnesium concentration. Under these conditions, MgtA production in the ΔcorA mutant did not require PhoP. Consistently, a ΔmgtA, but not a ΔphoP, mutation slightly reduced the magnesium content of the ΔcorA mutant. Synthetic phenotypes were observed when the ΔphoP and ΔcorA mutations were combined, including a strong reduction in growth and motility, independently of the extracellular magnesium concentration. The abundance of several proteins involved in flagella formation, chemotaxis and secretion was lowered by the ΔcorA and ΔphoP mutations in combination, but not alone. These findings unravel the importance of PhoP-dependent functions in the absence of CorA when magnesium is sufficient. Altogether, our data pinpoint a regulatory network, where the absence of CorA is sensed by the cell and compensated by MgtA and PhoP- dependent mechanisms.
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Affiliation(s)
- Selma Metaane
- Biochimie des Interactions Macromoléculaires, Institut Pasteur, CNRS UMR3528, Université Paris Cité, Paris, France
| | - Véronique Monteil
- Biochimie des Interactions Macromoléculaires, Institut Pasteur, CNRS UMR3528, Université Paris Cité, Paris, France
| | - Thibaut Douché
- Proteomic Platform, Mass Spectrometry for Biology Unit, Institut Pasteur, CNRS UAR 2024, Université Paris Cité, Paris, France
| | - Quentin Giai Gianetto
- Proteomic Platform, Mass Spectrometry for Biology Unit, Institut Pasteur, CNRS UAR 2024, Université Paris Cité, Paris, France
| | - Mariette Matondo
- Proteomic Platform, Mass Spectrometry for Biology Unit, Institut Pasteur, CNRS UAR 2024, Université Paris Cité, Paris, France
| | - Corinne Maufrais
- Bioinformatics and Biostatistics Hub, Institut Pasteur, Université Paris Cité, Paris, France
| | - Françoise Norel
- Biochimie des Interactions Macromoléculaires, Institut Pasteur, CNRS UMR3528, Université Paris Cité, Paris, France
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Padhi Y, Chatterjee S. XdfA, a novel membrane-associated DedA family protein of Xanthomonas campestris, is required for optimum virulence, maintenance of magnesium, and membrane homeostasis. mBio 2023; 14:e0136123. [PMID: 37498088 PMCID: PMC10470534 DOI: 10.1128/mbio.01361-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 06/15/2023] [Indexed: 07/28/2023] Open
Abstract
Xanthomonas campestris is an important member of the Xanthomonas group of phytopathogens that causes diseases in crucifers. In X. campestris, several virulence-associated functions, including some belonging to unknown predicted functions, have been implicated in the colonization and disease processes. However, the role of many of these unknown predicted proteins in Xanthomonas-host interaction and their exact physiological function is not clearly known. In this study, we identified a novel membrane-associated protein belonging to the DedA super family, XdfA, which is required for virulence in X. campestris. The DedA family of proteins are generally ubiquitous in bacteria; however, their function and actual physiological role are largely elusive. Characterization of ∆xdfA by homology modeling, membrane localization, and physiological studies indicated that XdfA is a membrane-associated protein that plays a role in the maintenance of membrane integrity. Furthermore, functional homology modeling analysis revealed that the XdfA exhibits structural similarity to a CorA-like magnesium transporter and is required for optimum growth under low magnesium ion concentration. We report for the first time that a putative DedA family of protein in Xanthomonas is required for optimum virulence and plays a role in the maintenance of membrane-associated functions and magnesium homeostasis. IMPORTANCE Bacterial DedA family proteins are involved in a range of cellular processes such as ion transport, signal transduction, and cell division. Here, we have discussed about a novel DedA family protein XdfA in Xanthomonas campestris pv. campestris that has a role in membrane homeostasis, magnesium transport, and virulence. Understanding membrane and magnesium homeostasis will aid in our comprehension of bacterial physiology and eventually will help us devise effective antimicrobial strategies to safeguard horticulturally and agriculturally important crop plants.
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Affiliation(s)
- Yasobanta Padhi
- Laboratory of Plant-Microbe Interactions, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
- Graduate Studies, Manipal Academy of Higher Education, Udupi, Karnataka, India
| | - Subhadeep Chatterjee
- Laboratory of Plant-Microbe Interactions, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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Tang L, Xiao L, Chen E, Lei X, Ren J, Yang Y, Xiao B, Gong C. Magnesium transporter CsMGT10 of tea plants plays a key role in chlorosis leaf vein greening. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107842. [PMID: 37352698 DOI: 10.1016/j.plaphy.2023.107842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/28/2023] [Accepted: 06/13/2023] [Indexed: 06/25/2023]
Abstract
Magnesium (Mg2+), as the central atom of chlorophyll, is the most abundant divalent cation for plant growth and development in living cells. MRS2/MGT magnesium transporters play important roles in coping with magnesium stress, chloroplast development and photosynthesis. However, the molecular mechanism of MGT influencing tea plant leaf vein color remains unknown. Here, we demonstrate that CsMGT10 may be a potential transporter influencing leaf vein color. CsMGT10 belongs to Clade A member of MRS2/MGT family. CsMGT10 has the highest expression level in leaves of tea plants. And it is mainly expressed in aboveground parts, especially in vascular bundles. Moreover, CsMGT10 localizes to the chloroplast envelope of tea plants with a high affinity to Mg2+. And the GMN motif is required for its magnesium transport function. Ectopic expression of CsMGT10 in Arabidopsis leaf variegation mutant var5-1 can restore green color of chlorosis leaf veins, and the contents of chlorophyll and carotenoid change significantly, proving its essential role in leaf vein greening. Furthermore, the chlorophyll and carotenoid of tea leaves treated with CsMGT10 antisense oligonucleotides also decrease significantly. Our findings indicate that CsMGT10 mainly acts as Mg2+ transporter in chloroplast envelope of leaf veins, which may play a key role in leaf vein greening of tea plants.
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Affiliation(s)
- Lei Tang
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Luodan Xiao
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China; Yibin Research Institute of Tea Industry, Yibin, 644000, China
| | - Enxiang Chen
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Xingyu Lei
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Jiejie Ren
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China
| | - Yajun Yang
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China; Tea Research Institute, Chinese Academy of Agricultural Sciences /National Center for Tea Improvement/Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agriculture and Rural Affairs, Hangzhou, 310008, China.
| | - Bin Xiao
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
| | - Chunmei Gong
- College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.
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6
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Uthayabalan S, Vishnu N, Madesh M, Stathopulos PB. The human MRS2 magnesium-binding domain is a regulatory feedback switch for channel activity. Life Sci Alliance 2023; 6:e202201742. [PMID: 36754568 PMCID: PMC9909464 DOI: 10.26508/lsa.202201742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/25/2023] [Accepted: 01/26/2023] [Indexed: 02/10/2023] Open
Abstract
Mitochondrial RNA splicing 2 (MRS2) forms a magnesium (Mg2+) entry protein channel in mitochondria. Whereas MRS2 contains two transmembrane domains constituting a pore on the inner mitochondrial membrane, most of the protein resides within the matrix. Yet, the precise structural and functional role of this obtrusive amino terminal domain (NTD) in human MRS2 is unknown. Here, we show that the MRS2 NTD self-associates into a homodimer, contrasting the pentameric assembly of CorA, an orthologous bacterial channel. Mg2+ and calcium suppress lower and higher order oligomerization of MRS2 NTD, whereas cobalt has no effect on the NTD but disassembles full-length MRS2. Mutating-pinpointed residues-mediating Mg2+ binding to the NTD not only selectively decreases Mg2+-binding affinity ∼sevenfold but also abrogates Mg2+ binding-induced secondary, tertiary, and quaternary structure changes. Disruption of NTD Mg2+ binding strikingly potentiates mitochondrial Mg2+ uptake in WT and Mrs2 knockout cells. Our work exposes a mechanism for human MRS2 autoregulation by negative feedback from the NTD and identifies a novel gain of function mutant with broad applicability to future Mg2+ signaling research.
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Affiliation(s)
- Sukanthathulse Uthayabalan
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - Neelanjan Vishnu
- Center for Mitochondrial Medicine, Department of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Muniswamy Madesh
- Center for Mitochondrial Medicine, Department of Medicine, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
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7
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Madaris TR, Venkatesan M, Maity S, Stein MC, Vishnu N, Venkateswaran MK, Davis JG, Ramachandran K, Uthayabalan S, Allen C, Osidele A, Stanley K, Bigham NP, Bakewell TM, Narkunan M, Le A, Karanam V, Li K, Mhapankar A, Norton L, Ross J, Aslam MI, Reeves WB, Singh BB, Caplan J, Wilson JJ, Stathopulos PB, Baur JA, Madesh M. Limiting Mrs2-dependent mitochondrial Mg 2+ uptake induces metabolic programming in prolonged dietary stress. Cell Rep 2023; 42:112155. [PMID: 36857182 PMCID: PMC10134742 DOI: 10.1016/j.celrep.2023.112155] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/28/2022] [Accepted: 02/08/2023] [Indexed: 03/02/2023] Open
Abstract
The most abundant cellular divalent cations, Mg2+ (mM) and Ca2+ (nM-μM), antagonistically regulate divergent metabolic pathways with several orders of magnitude affinity preference, but the physiological significance of this competition remains elusive. In mice consuming a Western diet, genetic ablation of the mitochondrial Mg2+ channel Mrs2 prevents weight gain, enhances mitochondrial activity, decreases fat accumulation in the liver, and causes prominent browning of white adipose. Mrs2 deficiency restrains citrate efflux from the mitochondria, making it unavailable to support de novo lipogenesis. As citrate is an endogenous Mg2+ chelator, this may represent an adaptive response to a perceived deficit of the cation. Transcriptional profiling of liver and white adipose reveals higher expression of genes involved in glycolysis, β-oxidation, thermogenesis, and HIF-1α-targets, in Mrs2-/- mice that are further enhanced under Western-diet-associated metabolic stress. Thus, lowering mMg2+ promotes metabolism and dampens diet-induced obesity and metabolic syndrome.
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Affiliation(s)
- Travis R Madaris
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Manigandan Venkatesan
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Soumya Maity
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Miriam C Stein
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Neelanjan Vishnu
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Mridula K Venkateswaran
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - James G Davis
- Department of Physiology and Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania, Philadelphia, PA 19103, USA
| | - Karthik Ramachandran
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | | | - Cristel Allen
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Ayodeji Osidele
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Kristen Stanley
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Nicholas P Bigham
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Terry M Bakewell
- Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Melanie Narkunan
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Amy Le
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Varsha Karanam
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Kang Li
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Aum Mhapankar
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Luke Norton
- Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Jean Ross
- Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - M Imran Aslam
- Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - W Brian Reeves
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Brij B Singh
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Jeffrey Caplan
- Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Justin J Wilson
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Peter B Stathopulos
- Department of Physiology and Pharmacology, Western University, London, ON N6A 5C1, Canada
| | - Joseph A Baur
- Department of Physiology and Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania, Philadelphia, PA 19103, USA.
| | - Muniswamy Madesh
- Department of Medicine, Center for Mitochondrial Medicine, University of Texas Health San Antonio, San Antonio, TX 78229, USA; Department of Medicine, Cardiology/Diabetes Divisions, University of Texas Health San Antonio, San Antonio, TX 78229, USA.
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8
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Pang J, Guo Q, Lu Z. The catalytic mechanism, metal dependence, substrate specificity, and biodiversity of ribonuclease H. Front Microbiol 2022; 13:1034811. [PMID: 36478866 PMCID: PMC9719913 DOI: 10.3389/fmicb.2022.1034811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 10/31/2022] [Indexed: 11/29/2023] Open
Abstract
Ribonucleoside monophosphates are inevitably misincorporated into the DNA genome inside cells, and they need to be excised to avoid chromosome instability. Ribonucleases H (RNases H) are enzymes that specifically hydrolyze the RNA strand of RNA/DNA hybrids or the RNA moiety from DNA containing a stretch of RNA, they therefore are required for DNA integrity. Extensive studies have drawn a mostly clear picture of the mechanisms of RNase H catalysis, but some questions are still lacking definitive answers. This review summarizes three alternative models of RNase H catalysis. The two-metal model is prevalent, but a three-metal model suggests the involvement of a third cation in catalysis. Apparently, the mechanisms underlying metal-dependent hydrolyzation are more complicated than initially thought. We also discuss the metal choices of RNases H and analyze how chemically similar cations function differently. Substrate and cleavage-site specificities vary among RNases H, and this is explicated in detail. An intriguing phenomenon is that organisms have diverse RNase H combinations, which may provide important hints to how rnh genes were transferred during evolution. Whether RNase H is essential for cellular growth, a key question in the study of in vivo functions, is also discussed. This article may aid in understanding the mechanisms underlying RNase H and in developing potentially promising applications of it.
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Affiliation(s)
| | | | - Zheng Lu
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, China
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9
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Induction of the Prenylated Stilbenoids Arachidin-1 and Arachidin-3 and Their Semi-Preparative Separation and Purification from Hairy Root Cultures of Peanut ( Arachis hypogaea L.). MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27186118. [PMID: 36144847 PMCID: PMC9504991 DOI: 10.3390/molecules27186118] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/09/2022] [Accepted: 09/15/2022] [Indexed: 11/29/2022]
Abstract
Prenylated stilbenoids such as arachidin-1 and arachidin-3 are stilbene derivatives that exhibit multiple pharmacological activities. We report an elicitation strategy using different combinations of cyclodextrin, hydrogen peroxide, methyl jasmonate and magnesium chloride to increase arachidin-1 and arachidin-3 production in peanut hairy root cultures. The treatment of hairy root cultures with cyclodextrin with hydrogen peroxide selectively enhanced arachidin-1 yield (132.6 ± 20.4 mg/L), which was 1.8-fold higher than arachidin-3. Similarly, cyclodextrin combined with methyl jasmonate selectively enhanced arachidin-3 yield (178.2 ± 6.8 mg/L), which was 5.5-fold higher than arachidin-1. Re-elicitation of the hairy root cultures further increased the levels of arachidin-1 and arachidin-3 by 24% and 42%, respectively. The ethyl acetate extract of the culture medium was consecutively fractionated by normal- and reversed-phase column chromatography, followed by semi-preparative HPLC purification on a C18 column to yield arachidin-1 with a recovery rate of 32% and arachidin-3 with a recovery rate of 39%, both at higher than 95% purity. This study provided a sustainable strategy to produce high-purity arachidin-1 and arachidin-3 using hairy root cultures of peanuts combined with column chromatography and semi-preparative HPLC.
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10
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Jin F, Huang Y, Hattori M. Recent Advances in the Structural Biology of Mg 2+ Channels and Transporters. J Mol Biol 2022; 434:167729. [PMID: 35841930 DOI: 10.1016/j.jmb.2022.167729] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 10/17/2022]
Abstract
Magnesium ions (Mg2+) are the most abundant divalent cations in living organisms and are essential for various physiological processes, including ATP utilization and the catalytic activity of numerous enzymes. Therefore, the homeostatic mechanisms associated with cellular Mg2+ are crucial for both eukaryotic and prokaryotic organisms and are thus strictly controlled by Mg2+ channels and transporters. Technological advances in structural biology, such as the expression screening of membrane proteins, in meso phase crystallization, and recent cryo-EM techniques, have enabled the structure determination of numerous Mg2+ channels and transporters. In this review article, we provide an overview of the families of Mg2+ channels and transporters (MgtE/SLC41, TRPM6/7, CorA/Mrs2, CorC/CNNM), and discuss the structural biology prospects based on the known structures of MgtE, TRPM7, CorA and CorC.
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Affiliation(s)
- Fei Jin
- State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Bioactive Small Molecules, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yichen Huang
- State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Bioactive Small Molecules, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Shanghai Key Laboratory of Bioactive Small Molecules, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai 200438, China.
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11
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Mo X, Pang P, Wang Y, Jiang D, Zhang M, Li Y, Wang P, Geng Q, Xie C, Du HN, Zhong B, Li D, Yao J. Tyrosine phosphorylation tunes chemical and thermal sensitivity of TRPV2 ion channel. eLife 2022; 11:78301. [PMID: 35686730 PMCID: PMC9282855 DOI: 10.7554/elife.78301] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/09/2022] [Indexed: 11/21/2022] Open
Abstract
Transient receptor potential vanilloid 2 (TRPV2) is a multimodal ion channel implicated in diverse physiopathological processes. Its important involvement in immune responses has been suggested such as in the macrophages’ phagocytosis process. However, the endogenous signaling cascades controlling the gating of TRPV2 remain to be understood. Here, we report that enhancing tyrosine phosphorylation remarkably alters the chemical and thermal sensitivities of TRPV2 endogenously expressed in rat bone marrow-derived macrophages and dorsal root ganglia (DRG) neurons. We identify that the protein tyrosine kinase JAK1 mediates TRPV2 phosphorylation at the molecular sites Tyr(335), Tyr(471), and Tyr(525). JAK1 phosphorylation is required for maintaining TRPV2 activity and the phagocytic ability of macrophages. We further show that TRPV2 phosphorylation is dynamically balanced by protein tyrosine phosphatase non-receptor type 1 (PTPN1). PTPN1 inhibition increases TRPV2 phosphorylation, further reducing the activation temperature threshold. Our data thus unveil an intrinsic mechanism where the phosphorylation/dephosphorylation dynamic balance sets the basal chemical and thermal sensitivity of TRPV2. Targeting this pathway will aid therapeutic interventions in physiopathological contexts. All the cells in our body have a membrane that separates their interior from the outside environment. However, studded across this barrier are numerous ion channels which allow the cell to sense and react to changes in its surroundings. This includes the ion channel TRPV2, which opens in response to mechanical pressure, certain chemical signals, or rising temperature levels. Many types of cell express TRPV2, including cells in the nervous system, muscle, and the immune system. However, despite being extensively studied, it is still not clear how TRPV2 opens and closes upon encountering high temperatures. In particular, previous work suggested that TRPV2 only responds when a cell’s surroundings reach around 52°C, which is a much higher temperature than cells inside our body normally encounter, even during a fever. To help resolve this mystery, Mo, Pang et al. studied TRPV2 in neurons responsible for sending sensory information and in immune cells called macrophages which had been extracted from rodents and grown in the laboratory. They found that when the cells were bathed in solutions containing magnesium ions, their TRPV2 channels were more sensitive to a number of different cues, including temperature. Further biochemical experiments showed that magnesium ions do not directly affect TRPV2, but increase the activity of another protein called JAK1. The magnesium ions caused JAK1 to attach specialized structures called phosphorylation tags to TRPV2. This modification (known as phosphorylation) made the channel more sensitive, allowing it to open in response to temperatures as low as 40°C. Mo, Pang et al. found that inhibiting JAK1 reduced the activity of TRPV2. Conversely, inhibiting the enzyme that removes the phosphorylation tags, called PTPN1, increased the channel’s activity. They also discovered that when JAK1 was blocked, macrophages were less able to ‘eat up’ bacteria, which is one of their main roles in the immune system. Taken together these experiments advance our understanding of how TRPV2 becomes active. The balance between the phosphorylation by JAK1 and the dephosphorylation by PTPN1 controls the temperature at which TRPV2 opens. Since TRPV2 contributes to several biological functions, including the development of the nervous system, the maintenance of heart muscles, and inflammation, these findings will be important to scientists in a broad range of fields.
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Affiliation(s)
- Xiaoyi Mo
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Peiyuan Pang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Yulin Wang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Dexiang Jiang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Mengyu Zhang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Yang Li
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Peiyu Wang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Qizhi Geng
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Chang Xie
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Hai-Ning Du
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Bo Zhong
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Dongdong Li
- Neuroscience Paris Seine, CNRS, INSERM, Sorbonne Université, Paris, France
| | - Jing Yao
- Department of Anesthesiology, Wuhan University, Wuhan, China
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12
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The stress sigma factor σS/RpoS counteracts Fur repression of genes involved in iron and manganese metabolism and modulates the ionome of Salmonella enterica serovar Typhimurium. PLoS One 2022; 17:e0265511. [PMID: 35358211 PMCID: PMC8970401 DOI: 10.1371/journal.pone.0265511] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/02/2022] [Indexed: 11/24/2022] Open
Abstract
In many Gram-negative bacteria, the stress sigma factor of RNA polymerase, σS/RpoS, remodels global gene expression to reshape the physiology of quiescent cells and ensure their survival under non-optimal growth conditions. In the foodborne pathogen Salmonella enterica serovar Typhimurium, σS is also required for biofilm formation and virulence. We have previously identified sRNAs genes positively controlled by σS in Salmonella, including the two paralogous sRNA genes, ryhB1 and ryhB2/isrE. Expression of ryhB1 and ryhB2 is repressed by the ferric uptake regulator Fur when iron is available. In this study, we show that σS alleviates Fur-mediated repression of the ryhB genes and of additional Fur target genes. Moreover, σS induces transcription of the manganese transporter genes mntH and sitABCD and prevents their repression, not only by Fur, but also by the manganese-responsive regulator MntR. These findings prompted us to evaluate the impact of a ΔrpoS mutation on the Salmonella ionome. Inductively coupled plasma mass spectrometry analyses revealed a significant effect of the ΔrpoS mutation on the cellular concentration of manganese, magnesium, cobalt and potassium. In addition, transcriptional fusions in several genes involved in the transport of these ions were regulated by σS. This study suggests that σS controls fluxes of ions that might be important for the fitness of quiescent cells. Consistent with this hypothesis, the ΔrpoS mutation extended the lag phase of Salmonella grown in rich medium supplemented with the metal ion chelator EDTA, and this effect was abolished when magnesium, but not manganese or iron, was added back. These findings unravel the importance of σS and magnesium in the regrowth potential of quiescent cells.
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Ge H, Wang Y, Chen J, Zhang B, Chen R, Lan W, Luan S, Yang L. An Arabidopsis vasculature distributed metal tolerance protein facilitates xylem magnesium diffusion to shoots under high-magnesium environments. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:166-182. [PMID: 34761874 DOI: 10.1111/jipb.13187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/10/2021] [Indexed: 06/13/2023]
Abstract
Magnesium (Mg2+ ) is an essential metal for plant growth; however, its over-accumulation in cells can be cytotoxic. The metal tolerance protein family (MTP) belongs to an ubiquitous family of cation diffusion facilitator (CDF) proteins that export divalent metal cations for metal homeostasis and tolerance in all organisms. We describe here the identification of MTP10 to be critical for xylem Mg homeostasis in Arabidopsis under high Mg2+ conditions. The Arabidopsis plant contains 12 MTP genes, and only knockout of MTP10 decreased the tolerance of high-Mg stress. The functional complementation assays in a Mg2+ -uptake-deficient bacterial strain MM281 confirmed that MTP10 conducted Mg2+ transport. MTP10 is localized to the plasma membrane of parenchyma cells around the xylem. Reciprocal grafting analysis further demonstrated that MTP10 functions in the shoot to determine the shoot growth phenotypes under high Mg2+ conditions. Moreover, compared to the wild type, the mtp10 mutant accumulated more Mg2+ in xylem sap under high-Mg stress. This study reveals that MTP10 facilitates Mg2+ diffusion from the xylem to shoots and thus determines Mg homeostasis in shoot vascular tissues during high-Mg stress.
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Affiliation(s)
- Haiman Ge
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Yuan Wang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai, 201602, China
| | - Jinlin Chen
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Bin Zhang
- Chinese Education Ministry's Key Laboratory of Western Resources and Modern Biotechnology, Key Laboratory of Biotechnology Shaanxi Province, College of Life Sciences, Northwest University, Xi'an, 710069, China
| | - Rui Chen
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Wenzhi Lan
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, California, 94702, USA
| | - Lei Yang
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, 210093, China
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14
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Wang R, Belew AT, Achuthan V, El Sayed N, DeStefano JJ. Physiological magnesium concentrations increase fidelity of diverse reverse transcriptases from HIV-1, HIV-2, and foamy virus, but not MuLV or AMV. J Gen Virol 2021; 102:001708. [PMID: 34904939 PMCID: PMC10019084 DOI: 10.1099/jgv.0.001708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Reverse transcriptases (RTs) are typically assayed using optimized Mg2+ concentrations (~5-10 mM) several-fold higher than physiological cellular free Mg2+ (~0.5 mM). Recent analyses demonstrated that HIV-1, but not Moloney murine leukaemia (MuLV) or avain myeloblastosis (AMV) virus RTs has higher fidelity in low Mg2+. In the current report, lacZα-based α-complementation assays were used to measure the fidelity of several RTs including HIV-1 (subtype B and A/E), several drug-resistant HIV-1 derivatives, HIV-2, and prototype foamy virus (PFV), all which showed higher fidelity using physiological Mg2+, while MuLV and AMV RTs demonstrated equivalent fidelity in low and high Mg2+. In 0.5 mM Mg2+, all RTs demonstrated approximately equal fidelity, except for PFV which showed higher fidelity. A Next Generation Sequencing (NGS) approach that used barcoding to determine mutation profiles was used to examine the types of mutations made by HIV-1 RT (type B) in low (0.5 mM) and high (6 mM) Mg2+ on a lacZα template. Unlike α-complementation assays which are dependent on LacZα activity, the NGS assay scores mutations at all positions and of every type. Consistent with α-complementation assays, a ~four-fold increase in mutations was observed in high Mg2+. These findings help explain why HIV-1 RT displays lower fidelity in vitro (with high Mg2+ concentrations) than other RTs (e.g. MuLV and AMV), yet cellular fidelity for these viruses is comparable. Establishing in vitro conditions that accurately represent RT's activity in cells is pivotal to determining the contribution of RT and other factors to the mutation profile observed with HIV-1.
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Affiliation(s)
- Ruofan Wang
- Department of Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, Maryland 20742, USA.,Present address: Vigene Biosciences, Rockville Maryland, USA
| | - Ashton T Belew
- Department of Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, Maryland 20742, USA
| | - Vasudevan Achuthan
- Department of Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, Maryland 20742, USA.,Present address: CRISPR Therapeutics, Cambridge, Massachusetts, USA
| | - Najib El Sayed
- Department of Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, Maryland 20742, USA.,Maryland Pathogen Research Institute, College Park, Maryland, USA
| | - Jeffrey J DeStefano
- Department of Cell Biology and Molecular Genetics, Bioscience Research Building, University of Maryland, College Park, Maryland 20742, USA.,Maryland Pathogen Research Institute, College Park, Maryland, USA
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16
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Abstract
Mg2+ is the most abundant divalent cation in living cells. It is essential for charge neutralization, macromolecule stabilization, and the assembly and activity of ribosomes and as a cofactor for enzymatic reactions. When experiencing low cytoplasmic Mg2+, bacteria adopt two main strategies: They increase the abundance and activity of Mg2+ importers and decrease the abundance of Mg2+-chelating ATP and rRNA. These changes reduce regulated proteolysis by ATP-dependent proteases and protein synthesis in a systemic fashion. In many bacterial species, the transcriptional regulator PhoP controls expression of proteins mediating these changes. The 5' leader region of some mRNAs responds to low cytoplasmic Mg2+ or to disruptions in translation of open reading frames in the leader regions by furthering expression of the associated coding regions, which specify proteins mediating survival when the cytoplasmic Mg2+ concentration is low. Microbial species often utilize similar adaptation strategies to cope with low cytoplasmic Mg2+ despite relying on different genes to do so.
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Affiliation(s)
- Eduardo A Groisman
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536, USA; .,Yale Microbial Sciences Institute, West Haven, Connecticut 06516, USA
| | - Carissa Chan
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut 06536, USA;
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17
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Wang X, An P, Gu Z, Luo Y, Luo J. Mitochondrial Metal Ion Transport in Cell Metabolism and Disease. Int J Mol Sci 2021; 22:ijms22147525. [PMID: 34299144 PMCID: PMC8305404 DOI: 10.3390/ijms22147525] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 12/19/2022] Open
Abstract
Mitochondria are vital to life and provide biological energy for other organelles and cell physiological processes. On the mitochondrial double layer membrane, there are a variety of channels and transporters to transport different metal ions, such as Ca2+, K+, Na+, Mg2+, Zn2+ and Fe2+/Fe3+. Emerging evidence in recent years has shown that the metal ion transport is essential for mitochondrial function and cellular metabolism, including oxidative phosphorylation (OXPHOS), ATP production, mitochondrial integrity, mitochondrial volume, enzyme activity, signal transduction, proliferation and apoptosis. The homeostasis of mitochondrial metal ions plays an important role in maintaining mitochondria and cell functions and regulating multiple diseases. In particular, channels and transporters for transporting mitochondrial metal ions are very critical, which can be used as potential targets to treat neurodegeneration, cardiovascular diseases, cancer, diabetes and other metabolic diseases. This review summarizes the current research on several types of mitochondrial metal ion channels/transporters and their functions in cell metabolism and diseases, providing strong evidence and therapeutic strategies for further insights into related diseases.
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Affiliation(s)
- Xuan Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
| | - Peng An
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA;
| | - Yongting Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
- Correspondence: (Y.L.); (J.L.)
| | - Junjie Luo
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; (X.W.); (P.A.)
- Correspondence: (Y.L.); (J.L.)
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18
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Jin F, Sun M, Fujii T, Yamada Y, Wang J, Maturana AD, Wada M, Su S, Ma J, Takeda H, Kusakizako T, Tomita A, Nakada-Nakura Y, Liu K, Uemura T, Nomura Y, Nomura N, Ito K, Nureki O, Namba K, Iwata S, Yu Y, Hattori M. The structure of MgtE in the absence of magnesium provides new insights into channel gating. PLoS Biol 2021; 19:e3001231. [PMID: 33905418 PMCID: PMC8104411 DOI: 10.1371/journal.pbio.3001231] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 05/07/2021] [Accepted: 04/12/2021] [Indexed: 12/15/2022] Open
Abstract
MgtE is a Mg2+ channel conserved in organisms ranging from prokaryotes to eukaryotes, including humans, and plays an important role in Mg2+ homeostasis. The previously determined MgtE structures in the Mg2+-bound, closed-state, and structure-based functional analyses of MgtE revealed that the binding of Mg2+ ions to the MgtE cytoplasmic domain induces channel inactivation to maintain Mg2+ homeostasis. There are no structures of the transmembrane (TM) domain for MgtE in Mg2+-free conditions, and the pore-opening mechanism has thus remained unclear. Here, we determined the cryo-electron microscopy (cryo-EM) structure of the MgtE-Fab complex in the absence of Mg2+ ions. The Mg2+-free MgtE TM domain structure and its comparison with the Mg2+-bound, closed-state structure, together with functional analyses, showed the Mg2+-dependent pore opening of MgtE on the cytoplasmic side and revealed the kink motions of the TM2 and TM5 helices at the glycine residues, which are important for channel activity. Overall, our work provides structure-based mechanistic insights into the channel gating of MgtE.
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Affiliation(s)
- Fei Jin
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Shanghai Key Laboratory of Bioactive Small Molecules, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
| | - Minxuan Sun
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Shanghai Key Laboratory of Bioactive Small Molecules, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
| | - Takashi Fujii
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Riken Quantitative Biology Center, Osaka, Japan
| | - Yurika Yamada
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Jin Wang
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Andrés D. Maturana
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Miki Wada
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Shichen Su
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Multiscale Research Institute for Complex Systems, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Hironori Takeda
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Atsuhiro Tomita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yoshiko Nakada-Nakura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kehong Liu
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tomoko Uemura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yayoi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Norimichi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Koichi Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Riken Quantitative Biology Center, Osaka, Japan
| | - So Iwata
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
- RIKEN SPring-8 Center, Kouto, Hyogo, Japan
| | - Ye Yu
- School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Shanghai Key Laboratory of Bioactive Small Molecules, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
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19
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Chaudhry AH, Nayab S, Hussain SB, Ali M, Pan Z. Current Understandings on Magnesium Deficiency and Future Outlooks for Sustainable Agriculture. Int J Mol Sci 2021; 22:1819. [PMID: 33673043 PMCID: PMC7917752 DOI: 10.3390/ijms22041819] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 11/24/2022] Open
Abstract
The productivity of agricultural produce is fairly dependent on the availability of nutrients and efficient use. Magnesium (Mg2+) is an essential macronutrient of living cells and is the second most prevalent free divalent cation in plants. Mg2+ plays a role in several physiological processes that support plant growth and development. However, it has been largely forgotten in fertilization management strategies to increase crop production, which leads to severe reductions in plant growth and yield. In this review, we discuss how the Mg2+ shortage induces several responses in plants at different levels: morphological, physiological, biochemical and molecular. Additionally, the Mg2+ uptake and transport mechanisms in different cellular organelles and the role of Mg2+ transporters in regulating Mg2+ homeostasis are also discussed. Overall, in this review, we critically summarize the available information about the responses of Mg deficiency on plant growth and development, which would facilitate plant scientists to create Mg2+-deficiency-resilient crops through agronomic and genetic biofortification.
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Affiliation(s)
- Ahmad Hassan Chaudhry
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China;
| | - Shafa Nayab
- Department of Horticulture, Muhammad Nawaz Shareef University of Agriculture, Multan 60000, Pakistan; (S.N.); (S.B.H.)
| | - Syed Bilal Hussain
- Department of Horticulture, Muhammad Nawaz Shareef University of Agriculture, Multan 60000, Pakistan; (S.N.); (S.B.H.)
| | - Muqarrab Ali
- Department of Agronomy, Muhammad Nawaz Shareef University of Agriculture, Multan 60000, Pakistan;
| | - Zhiyong Pan
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China;
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Vogel K, Greinert T, Reichard M, Held C, Harms H, Maskow T. Thermodynamics and Kinetics of Glycolytic Reactions. Part II: Influence of Cytosolic Conditions on Thermodynamic State Variables and Kinetic Parameters. Int J Mol Sci 2020; 21:ijms21217921. [PMID: 33113841 PMCID: PMC7663428 DOI: 10.3390/ijms21217921] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/18/2020] [Accepted: 10/20/2020] [Indexed: 01/22/2023] Open
Abstract
For systems biology, it is important to describe the kinetic and thermodynamic properties of enzyme-catalyzed reactions and reaction cascades quantitatively under conditions prevailing in the cytoplasm. While in part I kinetic models based on irreversible thermodynamics were tested, here in part II, the influence of the presumably most important cytosolic factors was investigated using two glycolytic reactions (i.e., the phosphoglucose isomerase reaction (PGI) with a uni-uni-mechanism and the enolase reaction with an uni-bi-mechanism) as examples. Crowding by macromolecules was simulated using polyethylene glycol (PEG) and bovine serum albumin (BSA). The reactions were monitored calorimetrically and the equilibrium concentrations were evaluated using the equation of state ePC-SAFT. The pH and the crowding agents had the greatest influence on the reaction enthalpy change. Two kinetic models based on irreversible thermodynamics (i.e., single parameter flux-force and two-parameter Noor model) were applied to investigate the influence of cytosolic conditions. The flux-force model describes the influence of cytosolic conditions on reaction kinetics best. Concentrations of magnesium ions and crowding agents had the greatest influence, while temperature and pH-value had a medium influence on the kinetic parameters. With this contribution, we show that the interplay of thermodynamic modeling and calorimetric process monitoring allows a fast and reliable quantification of the influence of cytosolic conditions on kinetic and thermodynamic parameters.
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Affiliation(s)
- Kristina Vogel
- UFZ - Helmholtz Centre for Environmental Research, Department Environmental Microbiology, Leipzig, Permoserstr. 15, D-04318 Leipzig, Germany; (K.V.); (M.R.); (H.H.)
- Institute for Drug Development, Leipzig University Medical School, Leipzig University, Bruederstr. 34, 04103 Leipzig, Germany
| | - Thorsten Greinert
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, Technische Universitaet Dortmund, Emil-Figge-Str. 70, 44227 Dortmund, Germany;
| | - Monique Reichard
- UFZ - Helmholtz Centre for Environmental Research, Department Environmental Microbiology, Leipzig, Permoserstr. 15, D-04318 Leipzig, Germany; (K.V.); (M.R.); (H.H.)
| | - Christoph Held
- Laboratory of Thermodynamics, Department of Biochemical and Chemical Engineering, Technische Universitaet Dortmund, Emil-Figge-Str. 70, 44227 Dortmund, Germany;
- Correspondence: (C.H.); (T.M.)
| | - Hauke Harms
- UFZ - Helmholtz Centre for Environmental Research, Department Environmental Microbiology, Leipzig, Permoserstr. 15, D-04318 Leipzig, Germany; (K.V.); (M.R.); (H.H.)
| | - Thomas Maskow
- UFZ - Helmholtz Centre for Environmental Research, Department Environmental Microbiology, Leipzig, Permoserstr. 15, D-04318 Leipzig, Germany; (K.V.); (M.R.); (H.H.)
- Correspondence: (C.H.); (T.M.)
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Chatterjee S, Brahma R, Raghuraman H. Gating-related Structural Dynamics of the MgtE Magnesium Channel in Membrane-Mimetics Utilizing Site-Directed Tryptophan Fluorescence. J Mol Biol 2020; 433:166691. [PMID: 33203509 DOI: 10.1016/j.jmb.2020.10.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/17/2020] [Accepted: 10/19/2020] [Indexed: 12/25/2022]
Abstract
Magnesium is the most abundant divalent cation present in the cell, and an abnormal Mg2+ homeostasis is associated with several diseases in humans. However, among ion channels, the mechanisms of intracellular regulation and transport of Mg2+ are poorly understood. MgtE is a homodimeric Mg2+-selective channel and is negatively regulated by high intracellular Mg2+ concentration where the cytoplasmic domain of MgtE acts as a Mg2+ sensor. Most of the previous biophysical studies on MgtE have been carried out in detergent micelles and the information regarding gating-related structural dynamics of MgtE in physiologically-relevant membrane environment is scarce. In this work, we monitored the changes in gating-related structural dynamics, hydration dynamics and conformational heterogeneity of MgtE in micelles and membranes using the intrinsic site-directed Trp fluorescence. For this purpose, we have engineered six single-Trp mutants in the functional Trp-less background of MgtE to obtain site-specific information on the gating-related structural dynamics of MgtE in membrane-mimetic systems. Our results indicate that Mg2+-induced gating might involve the possibility of a 'conformational wave' from the cytosolic N-domain to transmembrane domain of MgtE. Although MgtE is responsive to Mg2+-induced gating in both micelles and membranes, the organization and dynamics of MgtE is substantially altered in physiologically important phospholipid membranes compared to micelles. This is accompanied by significant changes in hydration dynamics and conformational heterogeneity. Overall, our results highlight the importance of lipid-protein interactions and are relevant for understanding gating mechanism of magnesium channels in general, and MgtE in particular.
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Affiliation(s)
- Satyaki Chatterjee
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, 1/AF Bidhannagar, Kolkata, India
| | - Rupasree Brahma
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, 1/AF Bidhannagar, Kolkata, India
| | - H Raghuraman
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, 1/AF Bidhannagar, Kolkata, India.
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22
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Minen RI, Martinez MP, Iglesias AA, Figueroa CM. Biochemical characterization of recombinant UDP-sugar pyrophosphorylase and galactinol synthase from Brachypodium distachyon. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 155:780-788. [PMID: 32866791 DOI: 10.1016/j.plaphy.2020.08.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 06/11/2023]
Abstract
Raffinose (Raf) protects plant cells during seed desiccation and under different abiotic stress conditions. The biosynthesis of Raf starts with the production of UDP-galactose by UDP-sugar pyrophosphorylase (USPPase) and continues with the synthesis of galactinol by galactinol synthase (GolSase). Galactinol is then used by Raf synthase to produce Raf. In this work, we report the biochemical characterization of USPPase (BdiUSPPase) and GolSase 1 (BdiGolSase1) from Brachypodium distachyon. The catalytic efficiency of BdiUSPPase was similar with galactose 1-phosphate and glucose 1-phosphate, but 5- to 17-fold lower with other sugar 1-phosphates. The catalytic efficiency of BdiGolSase1 with UDP-galactose was three orders of magnitude higher than with UDP-glucose. A structural model of BdiGolSase1 allowed us to determine the residues putatively involved in the binding of substrates. Among these, we found that Cys261 lies within the putative catalytic pocket. BdiGolSase1 was inactivated by oxidation with diamide and H2O2. The activity of the diamide-oxidized enzyme was recovered by reduction with dithiothreitol or E. coli thioredoxin, suggesting that BdiGolSase1 is redox-regulated.
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Affiliation(s)
- Romina I Minen
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - María P Martinez
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - Alberto A Iglesias
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina
| | - Carlos M Figueroa
- Instituto de Agrobiotecnología del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina.
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Gagnon V, Rodrigue-Morin M, Tremblay J, Wasserscheid J, Champagne J, Bellenger JP, Greer CW, Roy S. Life in mine tailings: microbial population structure across the bulk soil, rhizosphere, and roots of boreal species colonizing mine tailings in northwestern Québec. ANN MICROBIOL 2020. [DOI: 10.1186/s13213-020-01582-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Abstract
Purpose
Mining activities have negative effects on soil characteristics and can result in low pH, high heavy metal content, and limited levels of essential nutrients. A tailings storage area located in northwestern Québec showed natural colonization by plants from the adjacent natural environment. The objective of the study was to determine the main edaphic parameters that structured microbial populations associated with the indigenous woody plants that had naturally colonized the site.
Methods
Microbial populations were studied in the bulk soil, the rhizosphere, and inside plant roots using Illumina sequencing, ordination analysis (i.e., redundancy analysis (RDA) and principal coordinates analysis (PCoA)), ternary plotting, and statistical analysis (MANOVA).
Results
The main variables that drove the microbial community patterns were plant species and the tailings pH. Indeed, the main bacterial classes were Gammaproteobacteria and Deltaproteobacteria in both the rhizosphere and root endosphere. Analysis revealed that some dominant operational taxonomic units (e.g., Pseudomonas sp., Acinetobacter sp., and Delftia sp.) were present in increased proportions in roots for each plant species under study. This study also revealed that many of the most abundant fungal genera (e.g., Claussenomyces, Eupenicillium, and Trichoderma) were more abundant in the rhizosphere than in the root endosphere.
Conclusions
This comprehensive study of the microbial community dynamics in the bulk soil, rhizosphere, and root endosphere of boreal trees and shrubs could be beneficial in facilitating the rehabilitation of disturbed ecosystems.
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Klińska S, Jasieniecka-Gazarkiewicz K, Demski K, Banaś A. Editing of phosphatidic acid and phosphatidylethanolamine by acyl-CoA: lysophospholipid acyltransferases in developing Camelina sativa seeds. PLANTA 2020; 252:4. [PMID: 32524208 PMCID: PMC7286856 DOI: 10.1007/s00425-020-03408-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
The main source of polyunsaturated acyl-CoA in cytoplasmic acyl-CoA pool of Camelina sativa seeds are fatty acids derived from phosphatidylcholine followed by phosphatidic acid. Contribution of phosphatidylethanolamine is negligible. While phosphatidylethanolamine (PE) is the second most abundant phospholipid, phosphatidic acid (PA) only constitutes a small fraction of C. sativa seeds' polar lipids. In spite of this, the relative contribution of PA in providing fatty acids for the synthesis of acyl-CoA, supplying cytosolic acyl-CoA pool seems to be much higher than the contribution of PE. Our data indicate that up to 5% of fatty acids present in mature C. sativa seeds are first esterified with PA, in comparison to 2% first esterified with PE, before being transferred into acyl-CoA pool via backward reactions of either acyl-CoA:lysophosphatidic acid acyltransferases (CsLPAATs) or acyl-CoA:lysophoshatidylethanolamine acyltransferases (CsLPEATs). Those acyl-CoAs are later reused for lipid biosynthesis or remodelling. In the forward reactions both aforementioned acyltransferases display the highest activity at 30 °C. The spectrum of optimal pH differs for both enzymes with CsLPAATs most active between pH 7.5-9.0 and CsLPEATs between pH 9.0 to 10.0. Whereas addition of magnesium ions stimulates CsLPAATs, calcium and potassium ions inhibit them in concentrations of 0.05-2.0 mM. All three types of ions inhibit CsLPEATs activity. Both tested acyltransferases present the highest preferences towards 16:0-CoA and unsaturated 18-carbon acyl-CoAs in forward reactions. However, CsLPAATs preferentially utilise 18:1-CoA and CsLPEATs preferentially utilise 18:2-CoA while catalysing fatty acid remodelling of PA and PE, respectively.
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Affiliation(s)
- Sylwia Klińska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | | | - Kamil Demski
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
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25
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Precipitation of Inorganic Salts in Mitochondrial Matrix. MEMBRANES 2020; 10:membranes10050081. [PMID: 32349446 PMCID: PMC7281443 DOI: 10.3390/membranes10050081] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/17/2020] [Accepted: 04/19/2020] [Indexed: 11/17/2022]
Abstract
In the mitochondrial matrix, there are insoluble, osmotically inactive complexes that maintain a constant pH and calcium concentration. In the present paper, we examine the properties of insoluble calcium and magnesium salts, such as phosphates, carbonates and polyphosphates, which might play this role. We find that non-stoichiometric, magnesium-rich carbonated apatite, with very low crystallinity, precipitates in the matrix under physiological conditions. Precipitated salt acts as pH buffer, and, hence, can contribute in maintaining ATP production in ischemic conditions, which delays irreversible damage to heart and brain cells after stroke.
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Assessment of Cytotoxicity of Magnesium Oxide and Magnesium Hydroxide Nanoparticles using the Electric Cell-Substrate Impedance Sensing. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10062114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Magnesium (Mg)-based alloys have the potential for bone repair due to their properties of biodegradation, biocompatibility, and structural stability, which can eliminate the requirement for a second surgery for the removal of the implant. Nevertheless, uncontrolled degradation rate and possible cytotoxicity of the corrosion products at the implant sites are known current challenges for clinical applications. In this study, we assessed in vitro cytotoxicity of different concentrations (0 to 50 mM) of possible corrosion products in the form of magnesium oxide (MgO) and magnesium hydroxide (Mg(OH)2) nanoparticles (NPs) in human fetal osteoblast (hFOB) 1.19 cells. We measured cell proliferation, adhesion, migration, and cytotoxicity using a real-time, label-free, non-invasive electric cell-substrate impedance sensing (ECIS) system. Our results suggest that 1 mM concentrations of MgO/Mg(OH)2 NPs are tolerable in hFOB 1.19 cells. Based on our findings, we propose the development of innovative biodegradable Mg-based alloys for further in vivo animal testing and clinical trials in orthopedics.
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Beeby M, Ferreira JL, Tripp P, Albers SV, Mitchell DR. Propulsive nanomachines: the convergent evolution of archaella, flagella and cilia. FEMS Microbiol Rev 2020; 44:253-304. [DOI: 10.1093/femsre/fuaa006] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
ABSTRACT
Echoing the repeated convergent evolution of flight and vision in large eukaryotes, propulsive swimming motility has evolved independently in microbes in each of the three domains of life. Filamentous appendages – archaella in Archaea, flagella in Bacteria and cilia in Eukaryotes – wave, whip or rotate to propel microbes, overcoming diffusion and enabling colonization of new environments. The implementations of the three propulsive nanomachines are distinct, however: archaella and flagella rotate, while cilia beat or wave; flagella and cilia assemble at their tips, while archaella assemble at their base; archaella and cilia use ATP for motility, while flagella use ion-motive force. These underlying differences reflect the tinkering required to evolve a molecular machine, in which pre-existing machines in the appropriate contexts were iteratively co-opted for new functions and whose origins are reflected in their resultant mechanisms. Contemporary homologies suggest that archaella evolved from a non-rotary pilus, flagella from a non-rotary appendage or secretion system, and cilia from a passive sensory structure. Here, we review the structure, assembly, mechanism and homologies of the three distinct solutions as a foundation to better understand how propulsive nanomachines evolved three times independently and to highlight principles of molecular evolution.
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Affiliation(s)
- Morgan Beeby
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Josie L Ferreira
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Patrick Tripp
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - David R Mitchell
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
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Pohland AC, Schneider D. Mg2+ homeostasis and transport in cyanobacteria - at the crossroads of bacterial and chloroplast Mg2+ import. Biol Chem 2020; 400:1289-1301. [PMID: 30913030 DOI: 10.1515/hsz-2018-0476] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/19/2019] [Indexed: 12/29/2022]
Abstract
Magnesium cation (Mg2+) is the most abundant divalent cation in living cells, where it is required for various intracellular functions. In chloroplasts and cyanobacteria, established photosynthetic model systems, Mg2+ is the central ion in chlorophylls, and Mg2+ flux across the thylakoid membrane is required for counterbalancing the light-induced generation of a ΔpH across the thylakoid membrane. Yet, not much is known about Mg2+ homoeostasis, transport and distribution within cyanobacteria. However, Mg2+ transport across membranes has been studied in non-photosynthetic bacteria, and first observations and findings are reported for chloroplasts. Cyanobacterial cytoplasmic membranes appear to contain the well-characterized Mg2+ channels CorA and/or MgtE, which both facilitate transmembrane Mg2+ flux down the electrochemical gradient. Both Mg2+ channels are typical for non-photosynthetic bacteria. Furthermore, Mg2+ transporters of the MgtA/B family are also present in the cytoplasmic membrane to mediate active Mg2+ import into the bacterial cell. While the cytoplasmic membrane of cyanobacteria resembles a 'classical' bacterial membrane, essentially nothing is known about Mg2+ channels and/or transporters in thylakoid membranes of cyanobacteria or chloroplasts. As discussed here, at least one Mg2+ channelling protein must be localized within thylakoid membranes. Thus, either one of the 'typical' bacterial Mg2+ channels has a dual localization in the cytoplasmic plus the thylakoid membrane, or another, yet unidentified channel is present in cyanobacterial thylakoid membranes.
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Affiliation(s)
- Anne-Christin Pohland
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany
| | - Dirk Schneider
- Institut für Pharmazie und Biochemie, Johannes-Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany
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29
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Kwun MS, Lee DG. Quercetin-induced yeast apoptosis through mitochondrial dysfunction under the accumulation of magnesium in Candida albicans. Fungal Biol 2020; 124:83-90. [DOI: 10.1016/j.funbio.2019.11.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/23/2019] [Accepted: 11/25/2019] [Indexed: 02/02/2023]
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30
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Klińska S, Jasieniecka-Gazarkiewicz K, Banaś A. Acyl-CoA:lysophosphatidylcholine acyltransferases (LPCATs) of Camelina sativa seeds: biochemical properties and function. PLANTA 2019; 250:1655-1670. [PMID: 31407031 DOI: 10.1007/s00425-019-03248-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/25/2019] [Indexed: 05/20/2023]
Abstract
The transfer of polyunsaturated fatty acids from phosphatidylcholine to other lipids involves several enzymes. In Camelina sativa seeds, acyl-CoA:lysophosphatidylcholine acyltransferases could be one of the most important players in this process. The transfer of polyunsaturated fatty acids from the location of their synthesis (phosphatidylcholine) to other lipids, e.g., triacylglycerol, remains insufficiently understood. Several enzymes could be involved in this process. One of these enzymes is acyl-CoA:lysophosphatidylcholine acyltransferases (LPCATs). In Camelina sativa seeds, LPCATs could be one of the most important players in this process. Our data clearly indicate that the CsLPCATs present in developing seeds have the potential to transfer almost all polyunsaturated fatty acids synthesised on phosphatidylcholine to the acyl-CoA pool. CsLPCAT activity is the highest at 30 °C, and the enzymes operate well at a pH of 7.0-11.0, with the best activity at a pH of 9.0. The activity of CsLPCATs was inhibited by calcium and magnesium ions at a concentration of 0.05-2 mM. In the forward reaction, CsLPCATs preferentially utilise 18:2-CoA; however, other C18 unsaturated fatty acids are also well accepted. In the backward reactions, there is no clear discrimination between the C18 unsaturated fatty acids utilised by the enzymes for phosphatidylcholine remodelling. The activity of CsLPCATs does not differ much between the stages of seed development.
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Affiliation(s)
- Sylwia Klińska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
| | | | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307, Gdansk, Poland
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31
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Trachsel E, Redder P, Linder P, Armitano J. Genetic screens reveal novel major and minor players in magnesium homeostasis of Staphylococcus aureus. PLoS Genet 2019; 15:e1008336. [PMID: 31415562 PMCID: PMC6711546 DOI: 10.1371/journal.pgen.1008336] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/27/2019] [Accepted: 07/29/2019] [Indexed: 12/19/2022] Open
Abstract
Magnesium is one of the most abundant metal ions in living cells. Very specific and devoted transporters have evolved for transporting Mg2+ ions across the membrane and maintain magnesium homeostasis. Using genetic screens, we were able to identify the main players in magnesium homeostasis in the opportunistic pathogen Staphylococcus aureus. Here, we show that import of magnesium relies on the redundant activity of either CorA2 or MgtE since in absence of these two importers, bacteria require increased amounts of magnesium in the medium. A third CorA-like importer seems to play a minor role, at least under laboratory conditions. For export of magnesium, we identified two proteins, MpfA and MpfB. MpfA, is the main actor since it is essential for growth in high magnesium concentrations. We show that gain of function mutations or overexpression of the minor factor, MpfB, which is part of a sigmaB controlled stress response regulon, can compensate for the absence of MpfA.
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Affiliation(s)
- Emilie Trachsel
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Peter Redder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- LMGM UMR5100, Centre de Biologie Integrative, Paul Sabatier University, Toulouse, France
| | - Patrick Linder
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Joshua Armitano
- Department of Microbiology and Molecular Medicine, CMU, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- * E-mail:
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Chatterjee S, Das A, Raghuraman H. Biochemical and biophysical characterization of a prokaryotic Mg 2+ ion channel: Implications for cost-effective purification of membrane proteins. Protein Expr Purif 2019; 161:8-16. [PMID: 31028884 DOI: 10.1016/j.pep.2019.04.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 04/19/2019] [Indexed: 10/26/2022]
Abstract
Although magnesium is the second most abundant cation present in the cell, the transport mechanism of Mg2+ across membranes is poorly understood. Importantly, the prokaryotic MgtE Mg2+ channel is related to mammalian SLC41A1 transporters and, therefore, biochemical and biophysical characterization of MgtE and its orthologs assumes significance. To date, the purification and structure determination of MgtE from Thermus thermophilus has been carried out using the widely used nonionic detergent, n-dodecyl-β-d-maltopyranoside (DDM). However, DDM is an expensive detergent and alternative methods to produce high-quality proteins in stable and functional form will be practically advantageous to carry out structural studies in a cost-effective manner. In this work, we have utilized 'dual-detergent strategy' to successfully purify MgtE channel in a stable and functional form by employing relatively inexpensive detergents (Triton X-100 and Anzergent 3-14) for membrane solubilization and subsequently changed to DDM during purification. Our results show that Triton X-100 and Anzergent 3-14 extract MgtE well and the quality of purified protein is comparable to DDM-extracted MgtE. Interestingly, addition of high concentration of salt and glycerol during solubilization does not significantly affect the quantity and quality of MgtE. Importantly, limited proteolysis assay, circular dichroism spectroscopy and ensemble tryptophan fluorescence strongly support the use of Triton X-100, in particular, as an inexpensive, alternative detergent for the purification of MgtE without compromising the structural integrity of the channel and Mg2+-induced gating-related conformational dynamics. Overall, these results are relevant for the cost-effective purification of stable and functional membrane proteins in general, and magnesium channels, in particular.
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Affiliation(s)
- Satyaki Chatterjee
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, 1/AF Bidhannagar, Kolkata, 700 064, India
| | - Anindita Das
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, 1/AF Bidhannagar, Kolkata, 700 064, India
| | - H Raghuraman
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute, 1/AF Bidhannagar, Kolkata, 700 064, India.
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33
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Yang M, Wang X. Interactions between Microcystis aeruginosa and coexisting bisphenol A at different phosphorus levels. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 658:439-448. [PMID: 30579201 DOI: 10.1016/j.scitotenv.2018.12.089] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 06/09/2023]
Abstract
Microcystis aeruginosa is known as the main contributor to cyanobacterial bloom, which is prevalent globally and degrades freshwater systems worldwide. The argument that the introduction of anthropogenic contaminants in fresh water stimulates cyanobacterial growth and microcystin production has attracted widespread attention. Bisphenol A (BPA), one of the most abundant endocrine-disrupting compounds, is often detected in various water bodies due to its notably high annual levels of production and use. Research on the combined effects of endocrine-disrupting compounds and environmental factors on cyanobacteria remains limited. To investigate the mechanism of interactions between contaminants and cyanobacteria at the cellular and proteomic levels, the growth rate, chlorophyll-a content, photosynthetic activities, microcystin-LR (MC-LR) production and release, reactive oxygen species (ROS) content, superoxide dismutase (SOD) activities, malondialdehyde (MDA) content, and proteome expression of M. aeruginosa under 1 μM BPA stress at a standard phosphorus level were investigated. The results showed that stress responses to BPA included increases in the growth rate, chlorophyll-a content, and Fv/Fm and rETRmax values under the low phosphorus condition. Responses involving ROS, SOD, and MDA indicated that phosphorus sufficiency and BPA caused oxidative stress in M. aeruginosa. Moreover, phosphorus sufficiency and BPA stimulated the production and release of MCs. Compared to levels in the non-BPA-treated group, exposure of M. aeruginosa to BPA caused 72 up-regulated proteins, which were primarily associated with photosynthesis, ribosome, fatty acid biosynthesis, glycolysis/glyconeogenesis, and carbon fixation in photosynthetic organisms. The 105 down-regulated proteins were related to quorum sensing, base excision repair, ABC transporters, longevity regulating and cell cycle-caulobacter, suggesting that the cytotoxicity of cyanobacterial cells induced by BPA was significantly increased. These findings provide insights into the molecular mechanism of the effects of BPA and phosphorus on M. aeruginosa, suggesting that coexisting pollutants may cause greater harm to and health risks in the environment.
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Affiliation(s)
- Meng Yang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Xiangrong Wang
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China.
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Heeney DD, Yarov-Yarovoy V, Marco ML. Sensitivity to the two peptide bacteriocin plantaricin EF is dependent on CorC, a membrane-bound, magnesium/cobalt efflux protein. Microbiologyopen 2019; 8:e827. [PMID: 30891921 PMCID: PMC6854853 DOI: 10.1002/mbo3.827] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 01/31/2019] [Accepted: 02/04/2019] [Indexed: 12/12/2022] Open
Abstract
Lactic acid bacteria produce a variety of antimicrobial peptides known as bacteriocins. Most bacteriocins are understood to kill sensitive bacteria through receptor‐mediated disruptions. Here, we report on the identification of the Lactobacillus plantarum plantaricin EF (PlnEF) receptor. Spontaneous PlnEF‐resistant mutants of the PlnEF‐indicator strain L. plantarum NCIMB 700965 (LP965) were isolated and confirmed to maintain cellular ATP levels in the presence of PlnEF. Genome comparisons resulted in the identification of a single mutated gene annotated as the membrane‐bound, magnesium/cobalt efflux protein CorC. All isolates contained a valine (V) at position 334 instead of a glycine (G) in a cysteine‐β‐synthase domain at the C‐terminal region of CorC. In silico template‐based modeling of this domain indicated that the mutation resides in a loop between two β‐strands. The relationship between PlnEF, CorC, and metal homeostasis was supported by the finding that PlnEF‐resistance was lost when PlnEF was applied together with high concentrations of Mg2+, Co2+, Zn2+, or Cu2+. Lastly, PlnEF sensitivity was increased upon heterologous expression of LP965 corC but not the G334V CorC mutant in the PlnEF‐resistant strain Lactobacillus casei BL23. These results show that PlnEF kills sensitive bacteria by targeting CorC.
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Affiliation(s)
- Dustin D Heeney
- Department of Food Science & Technology, University of California-Davis, Davis, California
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California-Davis, Davis, California
| | - Maria L Marco
- Department of Food Science & Technology, University of California-Davis, Davis, California
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Hameed S, Hans S, Singh S, Fatima Z. Harnessing Metal Homeostasis Offers Novel and Promising Targets Against Candida albicans. Curr Drug Discov Technol 2019; 17:415-429. [PMID: 30827249 DOI: 10.2174/1570163816666190227231437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 01/08/2019] [Accepted: 01/30/2019] [Indexed: 11/22/2022]
Abstract
Fungal infections, particularly of Candida species, which are the commensal organisms of human, are one of the major debilitating diseases in immunocompromised patients. The limited number of antifungal drugs available to treat Candida infections, with the concomitant increasing incidence of multidrug-resistant (MDR) strains, further worsens the therapeutic options. Thus, there is an urgent need for the better understanding of MDR mechanisms, and their reversal, by employing new strategies to increase the efficacy and safety profiles of currently used therapies against the most prevalent human fungal pathogen, Candida albicans. Micronutrient availability during C. albicans infection is regarded as a critical factor that influences the progression and magnitude of the disease. Intracellular pathogens colonize a variety of anatomical locations that are likely to be scarce in micronutrients, as a defense strategy adopted by the host, known as nutritional immunity. Indispensable critical micronutrients are required both by the host and by C. albicans, especially as a cofactor in important metabolic functions. Since these micronutrients are not freely available, C. albicans need to exploit host reservoirs to adapt within the host for survival. The ability of pathogenic organisms, including C. albicans, to sense and adapt to limited micronutrients in the hostile environment is essential for survival and confers the basis of its success as a pathogen. This review describes that micronutrients availability to C. albicans is a key attribute that may be exploited when one considers designing strategies aimed at disrupting MDR in this pathogenic fungi. Here, we discuss recent advances that have been made in our understanding of fungal micronutrient acquisition and explore the probable pathways that may be utilized as targets.
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Affiliation(s)
- Saif Hameed
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
| | - Sandeep Hans
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
| | - Shweta Singh
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
| | - Zeeshan Fatima
- Amity Institute of Biotechnology, Amity University Haryana, Gurugram (Manesar)-122413, India
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Zhang L, Peng Y, Li J, Tian X, Chen Z. OsMGT1 Confers Resistance to Magnesium Deficiency By Enhancing the Import of Mg in Rice. Int J Mol Sci 2019; 20:ijms20010207. [PMID: 30626062 PMCID: PMC6337559 DOI: 10.3390/ijms20010207] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/30/2018] [Accepted: 01/03/2019] [Indexed: 02/02/2023] Open
Abstract
Magnesium (Mg) is an essential nutrient element for plant growth and plays an important role in numerous physiological and biochemical processes. Mg deficiency inhibits plant growth and has become a growing problem for crop productions in agriculture. However, the molecular mechanisms for the resistance to Mg deficiency in plants were not well understood. In this study, we identified a Mg transporter gene OsMGT1 that confers resistance to Mg deficiency in rice (Oryza sativa). The expression of OsMGT1 was highly induced by Mg deficiency in shoots. Investigation of tissue expression patterns revealed that OsMGT1 was mainly expressed in the phloem region; however, Mg deficiency remarkably enhanced its expression in xylem parenchyma and mesophyll cells in shoots. Knockout of OsMGT1 resulted in a significant reduction in Mg content and biomass when grown at Mg-limited conditions. Furthermore, the sensitivity to low-Mg in mutants was intensified by excessive calcium supply. In addition, overexpression of OsMGT1 increased Mg content and biomass under low-Mg supply. In conclusion, our results indicate that OsMGT1 plays an important role in rice Mg import and is required for the resistance to Mg deficiency, which can be utilized for molecular breeding of low-Mg tolerant plants.
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Affiliation(s)
- Ludan Zhang
- Root Biology Center, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Yuyang Peng
- Root Biology Center, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Jian Li
- Root Biology Center, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Xinyue Tian
- College of Crop Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Zhichang Chen
- Root Biology Center, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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The Significant Roles of Mg/Ca Ratio, Cl− and SO42− in Carbonate Mineral Precipitation by the Halophile Staphylococcus epidermis Y2. MINERALS 2018. [DOI: 10.3390/min8120594] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Carbonate precipitation induced by microorganisms has become a hot topic in the field of carbonate sedimentology, although the effects of magnesium on biomineral formation have rarely been studied. In experiments described here, magnesium sulfate and magnesium chloride were used to investigate the significant role played by Mg2+ on carbonate precipitation. In this study, Staphylococcus epidermidis Y2 was isolated and identified by 16S ribosomal DNA (rDNA) homology comparison and ammonia, pH, carbonic anhydrase, carbonate, and bicarbonate ions were monitored during laboratory experiments. The mineral phase, morphology, and elemental composition of precipitates were analyzed by XRD and SEM-EDS. Ultrathin slices of bacteria were analyzed by HRTEM-SAED and STEM. The results show that this bacterium releases ammonia and carbonic anhydrase to increase pH, and raise supersaturation via the large number of carbonate and bicarbonate ions that are released through carbon dioxide hydration catalyzed by carbonic anhydrase. The crystal cell density of monohydrocalcite is lower in a magnesium chloride medium, compared to one of magnesium sulfate. Crystals grow in the mode of a spiral staircase in a magnesium sulfate medium, but in a concentric circular pattern in a magnesium chloride medium. There was no obvious intracellular biomineralization taking place. The results presented here contribute to our understanding of the mechanisms of biomineralization, and to the role of Mg2+ in crystal form.
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Pokharel R, Gerrits R, Schuessler JA, Frings PJ, Sobotka R, Gorbushina AA, von Blanckenburg F. Magnesium Stable Isotope Fractionation on a Cellular Level Explored by Cyanobacteria and Black Fungi with Implications for Higher Plants. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:12216-12224. [PMID: 30351034 DOI: 10.1021/acs.est.8b02238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In a controlled growth experiment we found that the cyanobacterium Nostoc punctiforme has a bulk cell 26Mg/24Mg ratio (expressed as δ26Mg) that is -0.27‰ lower than the growth solution at a pH of ca. 5.9. This contrasts with a recently published δ26Mg value that was 0.65‰ higher than growth solution for the black fungus Knufia petricola at similar laboratory conditions, interpreted to reflect loss of 24Mg during cell growth. By a mass balance model constrained by δ26Mg in chlorophyll extract we inferred the δ26 Mg value of the main Mg compartments in a cyanobacteria cell: free cytosolic Mg (-2.64‰), chlorophyll (1.85‰), and the nonchlorophyll-bonded Mg compartments like ATP and ribosomes (-0.64‰). The lower δ26Mg found in Nostoc punctiforme would thus result from the absence of significant Mg efflux during cell growth in combination with either (a) discrimination against 26Mg during uptake by desolvation of Mg or transport across protein channels or (b) discrimination against 24Mg in the membrane transporter during efflux. The model predicts the preferential incorporation of 26Mg in cells and plant organs low in Mg and the absence of isotope fractionation in those high in Mg, corroborated by a compilation of Mg isotope ratios from fungi, bacteria, and higher plants.
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Affiliation(s)
- Rasesh Pokharel
- GFZ German Research Centre for Geosciences , Section 3.3, Earth Surface Geochemistry, Telegrafenberg, 14473 Potsdam , Germany
- Institute of Geological Sciences , Freie Universität Berlin , 12249 Berlin , Germany
| | - Ruben Gerrits
- Department 4, Materials & Environment , BAM Federal Institute for Materials Research & Testing , 12205 Berlin , Germany
- Department of Biology, Chemistry and Pharmacy , Freie Universität Berlin , 14195 Berlin , Germany
| | - Jan A Schuessler
- GFZ German Research Centre for Geosciences , Section 3.3, Earth Surface Geochemistry, Telegrafenberg, 14473 Potsdam , Germany
| | - Patrick J Frings
- GFZ German Research Centre for Geosciences , Section 3.3, Earth Surface Geochemistry, Telegrafenberg, 14473 Potsdam , Germany
| | - Roman Sobotka
- Institute of Microbiology , Centre Algatech , 379 81 Třebon , Czech Republic
| | - Anna A Gorbushina
- Institute of Geological Sciences , Freie Universität Berlin , 12249 Berlin , Germany
- Department 4, Materials & Environment , BAM Federal Institute for Materials Research & Testing , 12205 Berlin , Germany
- Department of Biology, Chemistry and Pharmacy , Freie Universität Berlin , 14195 Berlin , Germany
| | - Friedhelm von Blanckenburg
- GFZ German Research Centre for Geosciences , Section 3.3, Earth Surface Geochemistry, Telegrafenberg, 14473 Potsdam , Germany
- Institute of Geological Sciences , Freie Universität Berlin , 12249 Berlin , Germany
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Kimura T, Lorenz-Fonfria VA, Douki S, Motoki H, Ishitani R, Nureki O, Higashi M, Furutani Y. Vibrational and Molecular Properties of Mg2+ Binding and Ion Selectivity in the Magnesium Channel MgtE. J Phys Chem B 2018; 122:9681-9696. [DOI: 10.1021/acs.jpcb.8b07967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Tetsunari Kimura
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan
- Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan
| | - Victor A. Lorenz-Fonfria
- Institute of Molecular Science (ICMol), Universitat de València, Catedràtic José Beltrán Martínez 2, 46980 Paterna, Spain
- Department of Biochemistry and Molecular Biology, Universitat de València, Carrer Doctor Moliner 50, 46100 Burjassot, Spain
| | - Shintaro Douki
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hideyoshi Motoki
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Nakagami, Okinawa 903-0213, Japan
| | - Ryuichiro Ishitani
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Osamu Nureki
- Department of Biophysics and Biochemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masahiro Higashi
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Nakagami, Okinawa 903-0213, Japan
| | - Yuji Furutani
- Department of Life and Coordination-Complex Molecular Science, Institute for Molecular Science, National Institutes of Natural Sciences, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan
- Department of Structural Molecular Science, The Graduate University for Advanced Studies (SOKENDAI), 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585, Japan
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Workinger JL, Doyle RP, Bortz J. Challenges in the Diagnosis of Magnesium Status. Nutrients 2018; 10:E1202. [PMID: 30200431 PMCID: PMC6163803 DOI: 10.3390/nu10091202] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 08/24/2018] [Accepted: 08/27/2018] [Indexed: 12/31/2022] Open
Abstract
Magnesium is a critical mineral in the human body and is involved in ~80% of known metabolic functions. It is currently estimated that 60% of adults do not achieve the average dietary intake (ADI) and 45% of Americans are magnesium deficient, a condition associated with disease states like hypertension, diabetes, and neurological disorders, to name a few. Magnesium deficiency can be attributed to common dietary practices, medications, and farming techniques, along with estimates that the mineral content of vegetables has declined by as much as 80⁻90% in the last 100 years. However, despite this mineral's importance, it is poorly understood from several standpoints, not the least of which is its unique mechanism of absorption and sensitive compartmental handling in the body, making the determination of magnesium status difficult. The reliance on several popular sample assays has contributed to a great deal of confusion in the literature. This review will discuss causes of magnesium deficiency, absorption, handling, and compartmentalization in the body, highlighting the challenges this creates in determining magnesium status in both clinical and research settings.
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Affiliation(s)
- Jayme L Workinger
- Human Nutrition and Pharma, Balchem Corporation, 52 Sunrise Park Road, New Hampton, NY 10958, USA.
| | - Robert P Doyle
- Department of Chemistry, Center for Science and Technology, Syracuse University, 111 College Place, Syracuse, NY 13244, USA.
| | - Jonathan Bortz
- Human Nutrition and Pharma, Balchem Corporation, 52 Sunrise Park Road, New Hampton, NY 10958, USA.
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41
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Sohrabipour S, Sharifi MR, Sharifi M, Talebi A, Soltani N. Effect of magnesium sulfate administration to improve insulin resistance in type 2 diabetes animal model: using the hyperinsulinemic-euglycemic clamp technique. Fundam Clin Pharmacol 2018; 32:603-616. [PMID: 29869808 DOI: 10.1111/fcp.12387] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 05/08/2018] [Accepted: 06/01/2018] [Indexed: 12/15/2022]
Abstract
This study attempted to elucidate the possible mechanism of magnesium sulfate (MgSO4 ) administration on reducing insulin resistance in type 2 diabetic rats. Fifty Wistar rats were divided into five groups: NDC was fed the normal diet, CD received high-fat diet with 35 mg/kg of streptozotocin, CD-Mg animals received MgSO4 via drinking water, CD-Ins1, and CD-Ins2 animals treated with low or high dose of insulin. Body weight and blood glucose levels were measured weekly. Intraperitoneal glucose tolerance test (IPGTT), insulin tolerance test, and metabolic cage assessment were performed monthly. After 12 weeks, the hyperinsulinemic-euglycemic clamp was performed for all animals and blood sample was taken to measure glycated hemoglobin (HbA1c), plasma insulin, glucagon, calcium, and magnesium levels. Liver and gastrocnemius muscle were isolated to measure glucagon receptor (GR), Glucose 6 phosphatase (G6Pase), Phosphoenolpyruvate carboxykinase (Pepck) and Glucose transporter 4 (Glut4) genes expression and GLUT4 protein translocation into the cell membrane. Consuming of high-fat diet generated insulin-resistant rats. Magnesium or insulin therapy altered insulin resistance, blood glucose, IPGTT, gluconeogenesis pathway, GR, body weight, the percentage of body fat, and HbA1C in diabetic rats. Administrations of MgSO4 or insulin in Type 2 diabetes mellitus animals increase GLUT4 gene and protein expression. Mg could improve glucose tolerance via stimulation of Glut4 gene expression and translocation and also suppression of the gluconeogenesis pathway and GR gene expression. Mg also increased glucose infusion rate and displayed beneficial effects in the treatment of glucose metabolism and improved insulin resistance.
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Affiliation(s)
- Shahla Sohrabipour
- Endocrinology and Metabolism Research Center, Hormozgan University of Medical Sciences, Bandar, Abbas, Iran
| | - Mohammad Reza Sharifi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammadreza Sharifi
- Department of Genetics and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Ardeshir Talebi
- Department of Clinical Pathology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Nepton Soltani
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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42
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Gutekunst K, Hoffmann D, Westernströer U, Schulz R, Garbe-Schönberg D, Appel J. In-vivo turnover frequency of the cyanobacterial NiFe-hydrogenase during photohydrogen production outperforms in-vitro systems. Sci Rep 2018; 8:6083. [PMID: 29666458 PMCID: PMC5904137 DOI: 10.1038/s41598-018-24430-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/28/2018] [Indexed: 12/12/2022] Open
Abstract
Cyanobacteria provide all components for sunlight driven biohydrogen production. Their bidirectional NiFe-hydrogenase is resistant against low levels of oxygen with a preference for hydrogen evolution. However, until now it was unclear if its catalytic efficiency can keep pace with the photosynthetic electron transfer rate. We identified NikKLMQO (sll0381-sll0385) as a nickel transporter, which is required for hydrogen production. ICP-MS measurements were used to quantify hydrogenase molecules per cell. We found 400 to 2000 hydrogenase molecules per cell depending on the conditions. In-vivo turnover frequencies of the enzyme ranged from 62 H2/s in the wild type to 120 H2/s in a mutant during photohydrogen production. These frequencies are above maximum in-vivo photosynthetic electron transfer rates of 47 e-/s (equivalent to 24 H2/s). They are also above those of existing in-vitro systems working with unlimited electron supply and show that in-vivo photohydrogen production is limited by electron delivery to the enzyme.
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Affiliation(s)
- Kirstin Gutekunst
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany
| | - Dörte Hoffmann
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany
| | | | - Rüdiger Schulz
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany
| | | | - Jens Appel
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany.
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43
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Maruyama T, Imai S, Kusakizako T, Hattori M, Ishitani R, Nureki O, Ito K, Maturana AD, Shimada I, Osawa M. Functional roles of Mg 2+ binding sites in ion-dependent gating of a Mg 2+ channel, MgtE, revealed by solution NMR. eLife 2018; 7:31596. [PMID: 29611805 PMCID: PMC5882242 DOI: 10.7554/elife.31596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 03/25/2018] [Indexed: 01/30/2023] Open
Abstract
Magnesium ions (Mg2+) are divalent cations essential for various cellular functions. Mg2+ homeostasis is maintained through Mg2+ channels such as MgtE, a prokaryotic Mg2+ channel whose gating is regulated by intracellular Mg2+ levels. Our previous crystal structure of MgtE in the Mg2+-bound, closed state revealed the existence of seven crystallographically-independent Mg2+-binding sites, Mg1-Mg7. The role of Mg2+-binding to each site in channel closure remains unknown. Here, we investigated Mg2+-dependent changes in the structure and dynamics of MgtE using nuclear magnetic resonance spectroscopy. Mg2+-titration experiments, using wild-type and mutant forms of MgtE, revealed that the Mg2+ binding sites Mg1, Mg2, Mg3, and Mg6, exhibited cooperativity and a higher affinity for Mg2+, enabling the remaining Mg2+ binding sites, Mg4, Mg5, and Mg7, to play important roles in channel closure. This study revealed the role of each Mg2+-binding site in MgtE gating, underlying the mechanism of cellular Mg2+ homeostasis.
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Affiliation(s)
- Tatsuro Maruyama
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Shunsuke Imai
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Tsukasa Kusakizako
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China.,Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China.,Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai, China
| | - Ryuichiro Ishitani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Koichi Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
| | - Andrès D Maturana
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Ichio Shimada
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Masanori Osawa
- Department of Physical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.,Division of Physics for Life Functions, Faculty of Pharmacy, Keio University, Tokyo, Japan
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Maldonado R, Filarsky M, Grummt I, Längst G. Purine- and pyrimidine-triple-helix-forming oligonucleotides recognize qualitatively different target sites at the ribosomal DNA locus. RNA (NEW YORK, N.Y.) 2018; 24:371-380. [PMID: 29222118 PMCID: PMC5824356 DOI: 10.1261/rna.063800.117] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/30/2017] [Indexed: 05/04/2023]
Abstract
Triplexes are noncanonical DNA structures, which are functionally associated with regulation of gene expression through ncRNA targeting to chromatin. Based on the rules of Hoogsteen base-pairing, polypurine sequences of a duplex can potentially form triplex structures with single-stranded oligonucleotides. Prediction of triplex-forming sequences by bioinformatics analyses have revealed enrichment of potential triplex targeting sites (TTS) at regulatory elements, mainly in promoters and enhancers, suggesting a potential function of RNA-DNA triplexes in transcriptional regulation. Here, we have quantitatively evaluated the potential of different sequences of human and mouse ribosomal RNA genes (rDNA) to form triplexes at different salt and pH conditions. We show by biochemical and biophysical approaches that some of these predicted sequences form triplexes with high affinity, following the canonical rules for triplex formation. We further show that RNA triplex-forming oligos (TFOs) are more stable than their DNA counterpart, and point mutations strongly affect triplex formation. We further show differential sequence requirements of pyrimidine and purine TFO sequences for efficient binding, depending on the G-C content of the TTS. The unexpected sequence specificity, revealing distinct sequence requirements for purine and pyrimidine TFOs, shows that in addition to the Hoogsteen pairing rules, a sequence code and mutations have to be taken into account to predict genomic TTS.
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Affiliation(s)
- Rodrigo Maldonado
- Biochemistry Centre Regensburg (BCR), Universität Regensburg, 93053 Regensburg, Germany
| | - Michael Filarsky
- Biochemistry Centre Regensburg (BCR), Universität Regensburg, 93053 Regensburg, Germany
| | - Ingrid Grummt
- Division of Molecular Biology of the Cell II, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Gernot Längst
- Biochemistry Centre Regensburg (BCR), Universität Regensburg, 93053 Regensburg, Germany
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45
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Giménez-Mascarell P, Schirrmacher CE, Martínez-Cruz LA, Müller D. Novel Aspects of Renal Magnesium Homeostasis. Front Pediatr 2018; 6:77. [PMID: 29686978 PMCID: PMC5900390 DOI: 10.3389/fped.2018.00077] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 03/13/2018] [Indexed: 12/29/2022] Open
Abstract
Magnesium (Mg2+) is indispensable for several vital functions, such as neurotransmission, cardiac conductance, blood glucose, blood pressure regulation, and proper function of more than 300 enzymes. Thus, Mg2+ homeostasis is subject to tight regulation. Besides the fast and immediate regulation of plasma Mg2+, a major part of Mg2+ homeostasis is realized by a concerted action of epithelial molecular structures that tightly control intestinal uptake and renal absorption. This mechanism is provided by a combination of para- and transcellular pathways. Whereas the first pathway provides the organism with a maximal amount of vital substances by a minimal energy expenditure, the latter enables controlling and fine-tuning by means of local and regional regulatory systems and also, hormonal control. The paracellular pathway is driven by an electrochemical gradient and realized in principal by the tight junction (TJ), a supramolecular organization of membrane-bound proteins and their adaptor and scaffolding proteins. TJ determinants are claudins (CLDN), a family of membrane spanning proteins that generate a barrier or a pore between two adjacent epithelial cells. Many insights into molecular mechanisms of Mg2+ handling have been achieved by the identification of alterations and mutations in human genes which cause disorders of paracellular Mg2+ pathways (CLDN10, CLDN14, CLDN16, CLDN19). Also, in the distal convoluted tubule, a basolateral protein, CNNM2, causes if mutated, familial dominant and also recessive renal Mg2+ wasting, albeit its true function has not been clarified yet, but is assumed to play a key role in the transcellular pathway. Moreover, mutations in human genes that are involved in regulating these proteins directly or indirectly cause, if mutated human diseases, mostly in combination with comorbidities as diabetes, cystic renal disease, or metabolic abnormalities. Generation and characterization of animal models harboring the corresponding mutations have further contributed to the elucidation of physiology and pathophysiology of Mg2+ disorders. Finally, high-end crystallization techniques allow understanding of Mg2+ handling in more detail. As this field is rapidly growing, we describe here the principles of physiology and pathophysiology of epithelial transport of renal Mg2+ homeostasis with emphasis on recently identified mechanisms involved.
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Affiliation(s)
| | - Carlotta Else Schirrmacher
- Department of Pediatric Gastroenterology, Nephrology and Metabolism, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Dominik Müller
- Department of Pediatric Gastroenterology, Nephrology and Metabolism, Charité - Universitätsmedizin Berlin, Berlin, Germany
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47
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Pokharel R, Gerrits R, Schuessler JA, Floor GH, Gorbushina AA, von Blanckenburg F. Mg Isotope Fractionation during Uptake by a Rock-Inhabiting, Model Microcolonial Fungus Knufia petricola at Acidic and Neutral pH. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:9691-9699. [PMID: 28758385 DOI: 10.1021/acs.est.7b01798] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The model rock-inhabiting microcolonial fungus Knufia petricola fractionates stable Mg isotopes in a time- and pH-dependent manner. During growth, the increase of 26Mg/24Mg in the fungal cells relative to the growth media amounted to 0.65 ± 0.14‰ at pH 6 and 1.11 ± 0.35‰ at pH 3. We suggest a constant equilibrium fractionation factor during incorporation of Mg into ribosomes and ATP as a cause of enrichment of 26Mg in the cells. We suggest too that the proton gradient across the cell wall and cytoplasmic membrane controls Mg2+ transport into the fungal cell. As the strength of this gradient is a function of extracellular solution pH, the pH-dependence on Mg isotope fractionation is thus due to differences in fungal cell mass fluxes. Through a mass balance model we show that Mg uptake into the fungal cell is not associated with a unique Mg isotope fractionation factor. This Mg isotope fractionation dependence on pH might also be observed in any organism with cells that follow similar Mg uptake and metabolic pathways and serves to reveal Mg cycling in ecosystems.
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Affiliation(s)
- Rasesh Pokharel
- Section 3.3, Earth Surface Geochemistry, GFZ German Research Centre for Geosciences , Telegrafenberg, 14473 Potsdam, Germany
- Institute of Geological Sciences, Freie Universität Berlin , 12249 Berlin, Germany
| | - Ruben Gerrits
- Department 4, Materials & Environment, BAM Federal Institute for Materials Research & Testing , 12205 Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin , 14195 Berlin, Germany
| | - Jan A Schuessler
- Section 3.3, Earth Surface Geochemistry, GFZ German Research Centre for Geosciences , Telegrafenberg, 14473 Potsdam, Germany
| | - Geerke H Floor
- Section 3.3, Earth Surface Geochemistry, GFZ German Research Centre for Geosciences , Telegrafenberg, 14473 Potsdam, Germany
| | - Anna A Gorbushina
- Institute of Geological Sciences, Freie Universität Berlin , 12249 Berlin, Germany
- Department 4, Materials & Environment, BAM Federal Institute for Materials Research & Testing , 12205 Berlin, Germany
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin , 14195 Berlin, Germany
| | - Friedhelm von Blanckenburg
- Section 3.3, Earth Surface Geochemistry, GFZ German Research Centre for Geosciences , Telegrafenberg, 14473 Potsdam, Germany
- Institute of Geological Sciences, Freie Universität Berlin , 12249 Berlin, Germany
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48
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Tomita A, Zhang M, Jin F, Zhuang W, Takeda H, Maruyama T, Osawa M, Hashimoto KI, Kawasaki H, Ito K, Dohmae N, Ishitani R, Shimada I, Yan Z, Hattori M, Nureki O. ATP-dependent modulation of MgtE in Mg 2+ homeostasis. Nat Commun 2017; 8:148. [PMID: 28747715 PMCID: PMC5529423 DOI: 10.1038/s41467-017-00082-w] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 05/26/2017] [Indexed: 11/09/2022] Open
Abstract
Magnesium is an essential ion for numerous physiological processes. MgtE is a Mg2+ selective channel involved in the maintenance of intracellular Mg2+ homeostasis, whose gating is regulated by intracellular Mg2+ levels. Here, we report that ATP binds to MgtE, regulating its Mg2+-dependent gating. Crystal structures of MgtE–ATP complex show that ATP binds to the intracellular CBS domain of MgtE. Functional studies support that ATP binding to MgtE enhances the intracellular domain affinity for Mg2+ within physiological concentrations of this divalent cation, enabling MgtE to function as an in vivo Mg2+ sensor. ATP dissociation from MgtE upregulates Mg2+ influx at both high and low intracellular Mg2+ concentrations. Using site-directed mutagenesis and structure based-electrophysiological and biochemical analyses, we identify key residues and main structural changes involved in the process. This work provides the molecular basis of ATP-dependent modulation of MgtE in Mg2+ homeostasis. MgtE is an Mg2+ transporter involved in Mg2+ homeostasis. Here, the authors report that ATP regulates the Mg+2-dependent gating of MgtE and use X-ray crystallography combined with functional studies to propose the molecular mechanisms involved in this process.
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Affiliation(s)
- Atsuhiro Tomita
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Mingfeng Zhang
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China
| | - Fei Jin
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China
| | - Wenhui Zhuang
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China
| | - Hironori Takeda
- Faculty of Life Science, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Tatsuro Maruyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Masanori Osawa
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Ken-Ichi Hashimoto
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Hisashi Kawasaki
- Department of Green and Sustainable Chemistry, Tokyo Denki University, 5 Asahi-cho, Senju, Adachi-ku, Tokyo, 120-8551, Japan
| | - Koichi Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba, 277-8562, Japan
| | - Naoshi Dohmae
- Biomolecular Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Ryuichiro Ishitani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Zhiqiang Yan
- State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center of Genetics and Development, Institute of Brain Science, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China. .,Department of Human Anatomy, School of Basic Medicine Sciences, Southwest Medical University, Luzhou, Sichuan, 646000, China.
| | - Motoyuki Hattori
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, 2005 Songhu Road, Yangpu District, Shanghai, 200438, China.
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
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49
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Chen Y, Gao T, Wang Y, Yang G. Investigating the Influence of Magnesium Ions on p53-DNA Binding Using Atomic Force Microscopy. Int J Mol Sci 2017; 18:ijms18071585. [PMID: 28754018 PMCID: PMC5536072 DOI: 10.3390/ijms18071585] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/10/2017] [Accepted: 07/18/2017] [Indexed: 12/22/2022] Open
Abstract
p53 is a tumor suppressor protein that plays a significant role in apoptosis and senescence, preserving genomic stability, and preventing oncogene expression. Metal ions, such as magnesium and zinc ions, have important influences on p53–DNA interactions for stabilizing the structure of the protein and enhancing its affinity to DNA. In the present study, we systematically investigated the interaction of full length human protein p53 with DNA in metal ion solution by atomic force microscopy (AFM). The p53–DNA complexes at various p53 concentrations were scanned by AFM and their images are used to measure the dissociation constant of p53–DNA binding by a statistical method. We found that the dissociation constant of p53 binding DNA is 328.02 nmol/L in physiological buffer conditions. The influence of magnesium ions on p53–DNA binding was studied by AFM at various ion strengths through visualization. We found that magnesium ions significantly stimulate the binding of the protein to DNA in a sequence-independent manner, different from that stimulated by zinc. Furthermore, the high concentrations of magnesium ions can promote p53 aggregation and even lead to the formation of self-assembly networks of DNA and p53 proteins. We propose an aggregation and self-assembly model based on the present observation and discuss its biological meaning.
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Affiliation(s)
- Yang Chen
- School of Physics and Electronic Information, Wenzhou University, Wenzhou 325035, China.
| | - Tianyong Gao
- School of Physics and Electronic Information, Wenzhou University, Wenzhou 325035, China.
| | - Yanwei Wang
- School of Physics and Electronic Information, Wenzhou University, Wenzhou 325035, China.
| | - Guangcan Yang
- School of Physics and Electronic Information, Wenzhou University, Wenzhou 325035, China.
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50
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Zhao Y, Zhang JY, Zhang ZY, Tong TJ, Hao YH, Tan Z. Real-Time Detection Reveals Responsive Cotranscriptional Formation of Persistent Intramolecular DNA and Intermolecular DNA:RNA Hybrid G-Quadruplexes Stabilized by R-Loop. Anal Chem 2017; 89:6036-6042. [DOI: 10.1021/acs.analchem.7b00625] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Yang Zhao
- Department
of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Peking University Research Center on Aging, Beijing 100083, P.R. China
| | - Jia-yu Zhang
- State
Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Zong-yu Zhang
- Department
of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Peking University Research Center on Aging, Beijing 100083, P.R. China
| | - Tan-jun Tong
- Department
of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Peking University Research Center on Aging, Beijing 100083, P.R. China
| | - Yu-hua Hao
- State
Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Zheng Tan
- State
Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P.R. China
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