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Mota C, Webster M, Saidi M, Kapp U, Zubieta C, Giachin G, Manso JA, de Sanctis D. Metal ion activation and DNA recognition by the Deinococcus radiodurans manganese sensor DR2539. FEBS J 2024; 291:3384-3402. [PMID: 38652591 DOI: 10.1111/febs.17140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/14/2024] [Accepted: 04/10/2024] [Indexed: 04/25/2024]
Abstract
The accumulation of manganese ions is crucial for scavenging reactive oxygen species and protecting the proteome of Deinococcus radiodurans (Dr). However, metal homeostasis still needs to be tightly regulated to avoid toxicity. DR2539, a dimeric transcription regulator, plays a key role in Dr manganese homeostasis. Despite comprising three well-conserved domains - a DNA-binding domain, a dimerisation domain, and an ancillary domain - the mechanisms underlying both, metal ion activation and DNA recognition remain elusive. In this study, we present biophysical analyses and the structure of the dimerisation and DNA-binding domains of DR2539 in its holo-form and in complex with the 21 base pair pseudo-palindromic repeat of the dr1709 promoter region, shedding light on these activation and recognition mechanisms. The dimer presents eight manganese binding sites that induce structural conformations essential for DNA binding. The analysis of the protein-DNA interfaces elucidates the significance of Tyr59 and helix α3 sequence in the interaction with the DNA. Finally, the structure in solution as determined by small-angle X-ray scattering experiments and supported by AlphaFold modeling provides a model illustrating the conformational changes induced upon metal binding.
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Affiliation(s)
- Cristiano Mota
- ESRF - The European Synchrotron, Grenoble, France
- Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
- UCIBIO, Applied Molecular Biosciences Unit, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | | | | | - Ulrike Kapp
- ESRF - The European Synchrotron, Grenoble, France
| | | | | | - José Antonio Manso
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
- I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal
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2
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Schwab S, Dame RT. Identification, characterization and classification of prokaryotic nucleoid-associated proteins. Mol Microbiol 2024. [PMID: 39039769 DOI: 10.1111/mmi.15298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 07/02/2024] [Accepted: 07/06/2024] [Indexed: 07/24/2024]
Abstract
Common throughout life is the need to compact and organize the genome. Possible mechanisms involved in this process include supercoiling, phase separation, charge neutralization, macromolecular crowding, and nucleoid-associated proteins (NAPs). NAPs are special in that they can organize the genome at multiple length scales, and thus are often considered as the architects of the genome. NAPs shape the genome by either bending DNA, wrapping DNA, bridging DNA, or forming nucleoprotein filaments on the DNA. In this mini-review, we discuss recent advancements of unique NAPs with differing architectural properties across the tree of life, including NAPs from bacteria, archaea, and viruses. To help the characterization of NAPs from the ever-increasing number of metagenomes, we recommend a set of cheap and simple in vitro biochemical assays that give unambiguous insights into the architectural properties of NAPs. Finally, we highlight and showcase the usefulness of AlphaFold in the characterization of novel NAPs.
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Affiliation(s)
- Samuel Schwab
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands
| | - Remus T Dame
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands
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3
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Shi H, Fu Y, Kodyte V, Andreas A, Sachla AJ, Miller K, Shrestha R, Helmann JD, Glasfeld A, Ahuja S. Structural basis for transcription activation through cooperative recruitment of MntR. RESEARCH SQUARE 2024:rs.3.rs-4657015. [PMID: 39070638 PMCID: PMC11275975 DOI: 10.21203/rs.3.rs-4657015/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
The manganese transport regulator (MntR) from B. subtilis is a dual regulatory protein that responds to heightened Mn2+ availability in the cell by both repressing the expression of uptake transporters and activating the expression of efflux proteins. Recent work indicates that, in its role as an activator, MntR binds several sites upstream of the genes encoding Mn2+ exporters, leading to a cooperative response to manganese. Here, we use cryo-EM to explore the molecular basis of gene activation by MntR and report a structure of four MntR dimers bound to four 18-base pair sites across an 84-base pair regulatory region of the mneP promoter. Our structures, along with solution studies including mass photometry and in vivo transcription assays, reveal that MntR dimers employ polar and non-polar contacts to bind cooperatively to an array of low-affinity DNA-binding sites. These results reveal the molecular basis for cooperativity in the activation of manganese efflux.
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Affiliation(s)
- Haoyuan Shi
- Department of Chemistry, Reed College, Portland, Oregon 97202, USA
- Current address: Department of Chemical Pharmacology & Biochemistry, Oregon Health & Science University, Portland, OR 97239
| | - Yu Fu
- Department of Chemistry, Reed College, Portland, Oregon 97202, USA
- Current address: Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Vilmante Kodyte
- Department of Chemistry, Reed College, Portland, Oregon 97202, USA
| | - Amelie Andreas
- Department of Chemistry, Reed College, Portland, Oregon 97202, USA
| | - Ankita J. Sachla
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101
| | - Keiki Miller
- Department of Chemistry, Reed College, Portland, Oregon 97202, USA
| | | | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101
| | - Arthur Glasfeld
- Department of Chemistry, Reed College, Portland, Oregon 97202, USA
| | - Shivani Ahuja
- Department of Chemistry, Reed College, Portland, Oregon 97202, USA
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Shi H, Fu Y, Kodyte V, Andreas A, Sachla AJ, Miller K, Shrestha R, Helmann JD, Glasfeld A, Ahuja S. Structural basis for transcription activation through cooperative recruitment of MntR. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601288. [PMID: 38979284 PMCID: PMC11230367 DOI: 10.1101/2024.06.28.601288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The manganese transport regulator (MntR) from B. subtilis is a dual regulatory protein that responds to heightened Mn 2+ availability in the cell by both repressing the expression of uptake transporters and activating the expression of efflux proteins. Recent work indicates that, in its role as an activator, MntR binds several sites upstream of the genes encoding Mn 2+ exporters, leading to a cooperative response to manganese. Here, we use cryo-EM to explore the molecular basis of gene activation by MntR and report a structure of four MntR dimers bound to four 18-base pair sites across an 84-base pair regulatory region of the mneP promoter. Our structures, along with solution studies including mass photometry and in vivo transcription assays, reveal that MntR dimers employ polar and non-polar contacts to bind cooperatively to an array of low-affinity DNA-binding sites. These results reveal the molecular basis for cooperativity in the activation of manganese efflux.
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Radman K, Jelić Matošević Z, Žilić D, Crnolatac I, Bregović N, Kveder M, Piantanida I, Fernandes PA, Ašler IL, Bertoša B. Structural and dynamical changes of the Streptococcus gordonii metalloregulatory ScaR protein induced by Mn 2+ ion binding. Int J Biol Macromol 2023; 253:127572. [PMID: 37866578 DOI: 10.1016/j.ijbiomac.2023.127572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 10/24/2023]
Abstract
Divalent metal ions are essential micronutrients for many intercellular reactions. Maintaining their homeostasis is necessary for the survival of bacteria. In Streptococcus gordonii, one of the primary colonizers of the tooth surface, the cellular concentration of manganese ions (Mn2+) is regulated by the manganese-sensing transcriptional factor ScaR which controls the expression of proteins involved in manganese homeostasis. To resolve the molecular mechanism through which the binding of Mn2+ ions increases the binding affinity of ScaR to DNA, a variety of computational (QM and MD) and experimental (ITC, DSC, EMSA, EPR, and CD) methods were applied. The computational results showed that Mn2+ binding induces a conformational change in ScaR that primarily affects the position of the DNA binding domains and, consequently, the DNA binding affinity of the protein. In addition, experimental results revealed a 1:4 binding stoichiometry between ScaR dimer and Mn2+ ions, while the computational results showed that the binding of Mn2+ ions in the primary binding sites is sufficient to induce the observed conformational change of ScaR.
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Affiliation(s)
- Katarina Radman
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
| | - Zoe Jelić Matošević
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
| | - Dijana Žilić
- Division of Physical Chemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia.
| | - Ivo Crnolatac
- Division of Organic Chemistry & Biochemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia.
| | - Nikola Bregović
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
| | - Marina Kveder
- Division of Physical Chemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia.
| | - Ivo Piantanida
- Division of Organic Chemistry & Biochemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia.
| | - Pedro A Fernandes
- LAQV, REQUIMTE, Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal.
| | - Ivana Leščić Ašler
- Division of Physical Chemistry, Ruđer Bošković Institute, 10000 Zagreb, Croatia.
| | - Branimir Bertoša
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia.
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Abanoz-Seçgin B, Otur Ç, Okay S, Kurt-Kızıldoğan A. The regulatory role of Fur-encoding SCLAV_3199 in iron homeostasis in Streptomyces clavuligerus. Gene 2023:147594. [PMID: 37364696 DOI: 10.1016/j.gene.2023.147594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/09/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
Iron homeostasis is strictly regulated by complex cascades connected with secondary metabolism in bacteria. Ferric uptake regulators ('Fur's), siderophores, efflux systems, and two-component signal transduction systems are the leading players in response stimuli. However, these regulatory mechanisms remain to be elucidated in Streptomyces clavuligerus. Our study focused on unraveling a possible role of SCLAV_3199 which encodes a Fur family transcriptional regulator, particularly in iron regulation and at the global level in this species. We deleted the SCLAV_3199 gene in S. clavuligerus and compared gene expression differences with the wild-type strain based on iron availability by RNA-seq. We found a potential regulatory effect of SCLAV_3199 on many transcriptional regulators and transporters. Besides, the genes encoding iron sulfur binding proteins were overexpressed in the mutant in the presence of iron. Notably, catechol (SCLAV_5397), and hydroxamate-type (SCLAV_1952, SCLAV_4680) siderophore-related genes were upregulated in the mutant strain in iron scarcity. Concomitantly, S. clavuligerus Δ3199 produced 1.65 and 1.9 times more catechol and hydroxamate-type siderophores, respectively, than that of the wild type strain under iron depletion. Iron containing chemically defined medium did not favor antibiotic production in S. clavuligerus Δ3199 while fermentation in starch-asparagine medium led to improved cephamycin C (2.23-fold) and clavulanic acid (2.56-fold) production in the mutant compared to the control. However, better tunicamycin yield (2.64-fold) was obtained in trypticase soy broth-grown cultures of S. clavuligerus Δ3199. Our findings demonstrate that the SCLAV_3199 gene plays a significant role in regulating both iron homeostasis and secondary metabolite biosynthesis in S. clavuligerus.
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Affiliation(s)
- Büşra Abanoz-Seçgin
- Department of Agricultural Biotechnology, Ondokuz Mayıs University, Samsun 55139, Türkiye
| | - Çiğdem Otur
- Department of Agricultural Biotechnology, Ondokuz Mayıs University, Samsun 55139, Türkiye
| | - Sezer Okay
- Department of Vaccine Technology, Vaccine Institute, Hacettepe University, Ankara, 06230, Türkiye
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Marcos-Torres FJ, Juniar L, Griese JJ. The molecular mechanisms of the bacterial iron sensor IdeR. Biochem Soc Trans 2023:233013. [PMID: 37140254 DOI: 10.1042/bst20221539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/12/2023] [Accepted: 04/18/2023] [Indexed: 05/05/2023]
Abstract
Life came to depend on iron as a cofactor for many essential enzymatic reactions. However, once the atmosphere was oxygenated, iron became both scarce and toxic. Therefore, complex mechanisms have evolved to scavenge iron from an environment in which it is poorly bioavailable, and to tightly regulate intracellular iron contents. In bacteria, this is typically accomplished with the help of one key regulator, an iron-sensing transcription factor. While Gram-negative bacteria and Gram-positive species with low guanine-cytosine (GC) content generally use Fur (ferric uptake regulator) proteins to regulate iron homeostasis, Gram-positive species with high GC content use the functional homolog IdeR (iron-dependent regulator). IdeR controls the expression of iron acquisition and storage genes, repressing the former, and activating the latter in an iron-dependent manner. In bacterial pathogens such as Corynebacterium diphtheriae and Mycobacterium tuberculosis, IdeR is also involved in virulence, whereas in non-pathogenic species such as Streptomyces, it regulates secondary metabolism as well. Although in recent years the focus of research on IdeR has shifted towards drug development, there is much left to learn about the molecular mechanisms of IdeR. Here, we summarize our current understanding of how this important bacterial transcriptional regulator represses and activates transcription, how it is allosterically activated by iron binding, and how it recognizes its DNA target sites, highlighting the open questions that remain to be addressed.
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Affiliation(s)
- Francisco Javier Marcos-Torres
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-CSIC, 18011 Granada, Spain
| | - Linda Juniar
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
| | - Julia J Griese
- Department of Cell and Molecular Biology, Uppsala University, 751 24 Uppsala, Sweden
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Jelić Matošević Z, Radman K, Loubser J, Crnolatac I, Piantanida I, Cukrowski I, Ašler IL, Bertoša B. Structural Dynamics of the Bacillus subtilis MntR Transcription Factor Is Locked by Mn 2+ Binding. Int J Mol Sci 2023; 24:ijms24020957. [PMID: 36674477 PMCID: PMC9861239 DOI: 10.3390/ijms24020957] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/21/2022] [Accepted: 12/29/2022] [Indexed: 01/06/2023] Open
Abstract
Manganese (II) ions are essential for a variety of bacterial cellular processes. The transcription factor MntR is a metallosensor that regulates Mn2+ ion homeostasis in the bacterium Bacillus subtilis. Its DNA-binding affinity is increased by Mn2+ ion binding, allowing it to act as a transcriptional repressor of manganese import systems. Although experimentally well-researched, the molecular mechanism that regulates this process is still a puzzle. Computational simulations supported by circular dichroism (CD), differential scanning calorimetry (DSC) and native gel electrophoresis (native-PAGE) experiments were employed to study MntR structural and dynamical properties in the presence and absence of Mn2+ ions. The results of molecular dynamics (MD) simulations revealed that Mn2+ ion binding reduces the structural dynamics of the MntR protein and shifts the dynamic equilibrium towards the conformations adequate for DNA binding. Results of CD and DSC measurements support the computational results showing the change in helical content and stability of the MntR protein upon Mn2+ ion binding. Further, MD simulations show that Mn2+ binding induces polarization of the protein electrostatic potential, increasing the positive electrostatic potential of the DNA-binding helices in particular. In order to provide a deeper understanding of the changes in protein structure and dynamics due to Mn2+ binding, a mutant in which Mn2+ binding is mimicked by a cysteine bridge was constructed and also studied computationally and experimentally.
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Affiliation(s)
- Zoe Jelić Matošević
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia
| | - Katarina Radman
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia
| | - Jolene Loubser
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Ivo Crnolatac
- Division of Organic Chemistry & Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Ivo Piantanida
- Division of Organic Chemistry & Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Ignacy Cukrowski
- Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of Pretoria, Lynnwood Road, Hatfield, Pretoria 0002, South Africa
| | - Ivana Leščić Ašler
- Division of Physical Chemistry, Ruđer Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb, Croatia
| | - Branimir Bertoša
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102a, HR-10000 Zagreb, Croatia
- Correspondence: ; Tel.: +385-1-4606-132
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Rodriguez GM, Sharma N, Biswas A, Sharma N. The Iron Response of Mycobacterium tuberculosis and Its Implications for Tuberculosis Pathogenesis and Novel Therapeutics. Front Cell Infect Microbiol 2022; 12:876667. [PMID: 35646739 PMCID: PMC9132128 DOI: 10.3389/fcimb.2022.876667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/25/2022] [Indexed: 12/16/2022] Open
Abstract
Most pathogenic bacteria require iron for growth. However, this metal is not freely available in the mammalian host. Due to its poor solubility and propensity to catalyze the generation of reactive oxygen species, host iron is kept in solution bound to specialized iron binding proteins. Access to iron is an important factor in the outcome of bacterial infections; iron limitation frequently induces virulence and drives pathogenic interactions with host cells. Here, we review the response of Mycobacterium tuberculosis to changes in iron availability, the relevance of this response to TB pathogenesis, and its potential for the design of new therapeutic interventions.
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