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Senges CHR, Warmuth HL, Vázquez-Hernández M, Uzun HD, Sagurna L, Dietze P, Schmidt C, Mücher B, Herlitze S, Krämer U, Ott I, Pomorski TG, Bandow JE. Effects of 4-Br-A23187 on Bacillus subtilis cells and unilamellar vesicles reveal it to be a potent copper ionophore. Proteomics 2022; 22:e2200061. [PMID: 35666003 PMCID: PMC10140759 DOI: 10.1002/pmic.202200061] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/19/2022] [Accepted: 06/03/2022] [Indexed: 11/12/2022]
Abstract
Ionophores are small molecules or peptides that transport metal ions across biological membranes. Their transport capabilities are typically characterized in vitro using vesicles and single ion species. It is difficult to infer from these data which effects ionophores have on living cells in a complex environment (e.g. culture medium), since net ion movement is influenced by many factors including ion composition of the medium, concentration gradients, pH gradient, and protein-mediated transport processes across the membrane. To gain insights into the antibacterial mechanism of action of the semisynthetic polyether ionophore 4-Br-A23187, known to efficiently transport zinc and manganese in vitro, we investigated its effects on the gram-positive model organism Bacillus subtilis. In addition to monitoring cellular ion concentrations, the physiological impact of treatment was assessed on the proteome level. 4-Br-A23187 treatment resulted in an increase in intracellular copper levels, the extent of which depended on the copper concentration of the medium. Effects of copper accumulation mirrored by the proteomic response included oxidative stress, disturbance of proteostasis, metal and sulfur homeostasis. The antibiotic effect of 4-Br-A23187 is further aggravated by a decrease in intracellular manganese and magnesium. A liposome model confirmed that 4-Br-A23187 acts as copper ionophore in vitro. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Christoph H R Senges
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Helen L Warmuth
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Melissa Vázquez-Hernández
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Huriye Deniz Uzun
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801, Bochum, Germany
| | - Leonie Sagurna
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Pascal Dietze
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Claudia Schmidt
- Inorganic and Organometallic Medicinal Chemistry, Faculty of Life Sciences, Technical University Braunschweig, 38106, Braunschweig, Germany.,Institute for Drug Research, Hebrew University of Jerusalem, Jerusalem, 9112001, Israel
| | - Brix Mücher
- Department of Zoology and Neurobiology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Stefan Herlitze
- Department of Zoology and Neurobiology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Ute Krämer
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801, Bochum, Germany
| | - Ingo Ott
- Inorganic and Organometallic Medicinal Chemistry, Faculty of Life Sciences, Technical University Braunschweig, 38106, Braunschweig, Germany
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry, Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801, Bochum, Germany
| | - Julia E Bandow
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44801, Bochum, Germany
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Pilotto S, Fouqueau T, Lukoyanova N, Sheppard C, Lucas-Staat S, Díaz-Santín LM, Matelska D, Prangishvili D, Cheung ACM, Werner F. Structural basis of RNA polymerase inhibition by viral and host factors. Nat Commun 2021; 12:5523. [PMID: 34535646 PMCID: PMC8448823 DOI: 10.1038/s41467-021-25666-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/19/2021] [Indexed: 12/26/2022] Open
Abstract
RNA polymerase inhibition plays an important role in the regulation of transcription in response to environmental changes and in the virus-host relationship. Here we present the high-resolution structures of two such RNAP-inhibitor complexes that provide the structural bases underlying RNAP inhibition in archaea. The Acidianus two-tailed virus encodes the RIP factor that binds inside the DNA-binding channel of RNAP, inhibiting transcription by occlusion of binding sites for nucleic acid and the transcription initiation factor TFB. Infection with the Sulfolobus Turreted Icosahedral Virus induces the expression of the host factor TFS4, which binds in the RNAP funnel similarly to eukaryotic transcript cleavage factors. However, TFS4 allosterically induces a widening of the DNA-binding channel which disrupts trigger loop and bridge helix motifs. Importantly, the conformational changes induced by TFS4 are closely related to inactivated states of RNAP in other domains of life indicating a deep evolutionary conservation of allosteric RNAP inhibition.
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Affiliation(s)
- Simona Pilotto
- RNAP Laboratory, Institute for Structural and Molecular Biology, University College London, London, UK
| | - Thomas Fouqueau
- RNAP Laboratory, Institute for Structural and Molecular Biology, University College London, London, UK
| | - Natalya Lukoyanova
- Institute for Structural and Molecular Biology, Birkbeck College, London, UK
| | - Carol Sheppard
- Section of Virology, Department of Infectious disease, Imperial College London, London, UK
| | | | | | - Dorota Matelska
- RNAP Laboratory, Institute for Structural and Molecular Biology, University College London, London, UK
| | | | | | - Finn Werner
- RNAP Laboratory, Institute for Structural and Molecular Biology, University College London, London, UK.
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Wenck BR, Santangelo TJ. Archaeal transcription. Transcription 2020; 11:199-210. [PMID: 33112729 PMCID: PMC7714419 DOI: 10.1080/21541264.2020.1838865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 12/15/2022] Open
Abstract
Increasingly sophisticated biochemical and genetic techniques are unraveling the regulatory factors and mechanisms that control gene expression in the Archaea. While some similarities in regulatory strategies are universal, archaeal-specific regulatory strategies are emerging to complement a complex patchwork of shared archaeal-bacterial and archaeal-eukaryotic regulatory mechanisms employed in the archaeal domain. The prokaryotic archaea encode core transcription components with homology to the eukaryotic transcription apparatus and also share a simplified eukaryotic-like initiation mechanism, but also deploy tactics common to bacterial systems to regulate promoter usage and influence elongation-termination decisions. We review the recently established complete archaeal transcription cycle, highlight recent findings of the archaeal transcription community and detail the expanding post-initiation regulation imposed on archaeal transcription.
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Affiliation(s)
- Breanna R. Wenck
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
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Effects on growth by changes of the balance between GreA, GreB, and DksA suggest mutual competition and functional redundancy in Escherichia coli. J Bacteriol 2011; 194:261-73. [PMID: 22056927 DOI: 10.1128/jb.06238-11] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It is well known that ppGpp and DksA interact with bacterial RNA polymerase (RNAP) to alter promoter activity. This study suggests that GreA plays a major role and GreB plays a minor role in the ppGpp-DksA regulatory network. We present evidence that DksA and GreA/GreB are redundant and/or share similar functions: (i) on minimal medium GreA overproduction suppresses the growth defects of a dksA mutant; (ii) GreA and DksA overexpression partially suppresses the auxotrophy of a ppGpp-deficient strain; (iii) microarrays show that many genes are regulated similarly by GreA and DksA. We also find instances where GreA and DksA seem to act in opposition: (i) complete suppression of auxotrophy occurs by overexpression of GreA or DksA only in the absence of the other protein; (ii) PgadA and PgadE promoter fusions, along with many other genes, are dramatically affected in vivo by GreA overproduction only when DksA is absent; (iii) GreA and DksA show opposite regulation of a subset of genes. Mutations in key acidic residues of GreA and DksA suggest that properties seen here probably are not explained by known biochemical activities of these proteins. Our results indicate that the general pattern of gene expression and, in turn, the ability of Escherichia coli to grow under a defined condition are the result of a complex interplay between GreA, GreB, and DksA that also involves mutual control of their gene expression, competition for RNA polymerase binding, and similar or opposite action on RNA polymerase activity.
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