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Burgardt NI, Melian NA, González Flecha FL. Copper resistance in the cold: Genome analysis and characterisation of a P IB-1 ATPase in Bizionia argentinensis. ENVIRONMENTAL MICROBIOLOGY REPORTS 2024; 16:e13278. [PMID: 38943264 PMCID: PMC11213822 DOI: 10.1111/1758-2229.13278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 04/19/2024] [Indexed: 07/01/2024]
Abstract
Copper homeostasis is a fundamental process in organisms, characterised by unique pathways that have evolved to meet specific needs while preserving core resistance mechanisms. While these systems are well-documented in model bacteria, information on copper resistance in species adapted to cold environments is scarce. This study investigates the potential genes related to copper homeostasis in the genome of Bizionia argentinensis (JUB59-T), a psychrotolerant bacterium isolated from Antarctic seawater. We identified several genes encoding proteins analogous to those crucial for copper homeostasis, including three sequences of copper-transport P1B-type ATPases. One of these, referred to as BaCopA1, was chosen for cloning and expression in Saccharomyces cerevisiae. BaCopA1 was successfully integrated into yeast membranes and subsequently extracted with detergent. The purified BaCopA1 demonstrated the ability to catalyse ATP hydrolysis at low temperatures. Structural models of various BaCopA1 conformations were generated and compared with mesophilic and thermophilic homologous structures. The significant conservation of critical residues and structural similarity among these proteins suggest a shared reaction mechanism for copper transport. This study is the first to report a psychrotolerant P1B-ATPase that has been expressed and purified in a functional form.
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Affiliation(s)
- Noelia I. Burgardt
- Laboratorio de Biofísica Molecular, Facultad de Farmacia y Bioquímica, Instituto de Química y Fisicoquímica BiológicasUniversidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
- Present address:
Departamento de Ciencia y TecnologíaUniversidad Nacional de QuilmesBernalArgentina
| | - Noelia A. Melian
- Laboratorio de Biofísica Molecular, Facultad de Farmacia y Bioquímica, Instituto de Química y Fisicoquímica BiológicasUniversidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
| | - F. Luis González Flecha
- Laboratorio de Biofísica Molecular, Facultad de Farmacia y Bioquímica, Instituto de Química y Fisicoquímica BiológicasUniversidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y TécnicasBuenos AiresArgentina
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Njenga R, Boele J, Öztürk Y, Koch HG. Coping with stress: How bacteria fine-tune protein synthesis and protein transport. J Biol Chem 2023; 299:105163. [PMID: 37586589 PMCID: PMC10502375 DOI: 10.1016/j.jbc.2023.105163] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/18/2023] Open
Abstract
Maintaining a functional proteome under different environmental conditions is challenging for every organism, in particular for unicellular organisms, such as bacteria. In order to cope with changing environments and stress conditions, bacteria depend on strictly coordinated proteostasis networks that control protein production, folding, trafficking, and degradation. Regulation of ribosome biogenesis and protein synthesis are cornerstones of this cellular adaptation in all domains of life, which is rationalized by the high energy demand of both processes and the increased resistance of translationally silent cells against internal or external poisons. Reduced protein synthesis ultimately also reduces the substrate load for protein transport systems, which are required for maintaining the periplasmic, inner, and outer membrane subproteomes. Consequences of impaired protein transport have been analyzed in several studies and generally induce a multifaceted response that includes the upregulation of chaperones and proteases and the simultaneous downregulation of protein synthesis. In contrast, generally less is known on how bacteria adjust the protein targeting and transport machineries to reduced protein synthesis, e.g., when cells encounter stress conditions or face nutrient deprivation. In the current review, which is mainly focused on studies using Escherichia coli as a model organism, we summarize basic concepts on how ribosome biogenesis and activity are regulated under stress conditions. In addition, we highlight some recent developments on how stress conditions directly impair protein targeting to the bacterial membrane. Finally, we describe mechanisms that allow bacteria to maintain the transport of stress-responsive proteins under conditions when the canonical protein targeting pathways are impaired.
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Affiliation(s)
- Robert Njenga
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany; Faculty of Biology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Julian Boele
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany.
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Ishihara JI, Mekubo T, Kusaka C, Kondo S, Oiko R, Igarashi K, Aiba H, Ishikawa S, Ogasawara N, Oshima T, Takahashi H. A critical role of the periplasm in copper homeostasis in Gram-negative bacteria. Biosystems 2023; 231:104980. [PMID: 37453610 DOI: 10.1016/j.biosystems.2023.104980] [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: 03/14/2023] [Revised: 06/18/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
Copper is essential for life, but is toxic in excess. Copper homeostasis is achieved in the cytoplasm and the periplasm as a unique feature of Gram-negative bacteria. Especially, it has become clear the role of the periplasm and periplasmic proteins regarding whole-cell copper homeostasis. Here, we addressed the role of the periplasm and periplasmic proteins in copper homeostasis using a Systems Biology approach integrating experiments with models. Our analysis shows that most of the copper-bound molecules localize in the periplasm but not cytoplasm, suggesting that Escherichia coli utilizes the periplasm to sense the copper concentration in the medium and sequester copper ions. In particular, a periplasmic multi-copper oxidase CueO and copper-responsive transcriptional factor CusS contribute both to protection against Cu(I) toxicity and to incorporating copper into the periplasmic components/proteins. We propose that Gram-negative bacteria have evolved mechanisms to sense and store copper in the periplasm to expand their living niches.
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Affiliation(s)
- Jun-Ichi Ishihara
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba, 260-8673, Japan
| | - Tomohiro Mekubo
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Chikako Kusaka
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Suguru Kondo
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Ryotaro Oiko
- Graduate School of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu City, Toyama, 939-0398, Japan
| | - Kensuke Igarashi
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2-17-2-1 Tsukisamu-Higashi, Toyohiraku, Sapporo, Hokkaido, 062-8517, Japan
| | - Hirofumi Aiba
- Graduate School of Pharmaceutical Sciences, Nagoya University, Pharmaceutical Sciences Building, Furocho, Chikusa-ku, Aichi, 464-8601, Japan
| | - Shu Ishikawa
- Graduate School of Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku Kobe, 657-8501, Japan
| | - Naotake Ogasawara
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Taku Oshima
- Graduate School of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu City, Toyama, 939-0398, Japan.
| | - Hiroki Takahashi
- Medical Mycology Research Center, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba, 260-8673, Japan; Molecular Chirality Research Center, Chiba University, Chiba, Japan; Plant Molecular Science Center, Chiba University, Chiba, Japan.
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Metabolic Sensing of Extracytoplasmic Copper Availability via Translational Control by a Nascent Exported Protein. mBio 2023; 14:e0304022. [PMID: 36598193 PMCID: PMC9973294 DOI: 10.1128/mbio.03040-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Metabolic sensing is a crucial prerequisite for cells to adjust their physiology to rapidly changing environments. In bacteria, the response to intra- and extracellular ligands is primarily controlled by transcriptional regulators, which activate or repress gene expression to ensure metabolic acclimation. Translational control, such as ribosomal stalling, can also contribute to cellular acclimation and has been shown to mediate responses to changing intracellular molecules. In the current study, we demonstrate that the cotranslational export of the Rhodobacter capsulatus protein CutF regulates the translation of the downstream cutO-encoded multicopper oxidase CutO in response to extracellular copper (Cu). Our data show that CutF, acting as a Cu sensor, is cotranslationally exported by the signal recognition particle pathway. The binding of Cu to the periplasmically exposed Cu-binding motif of CutF delays its cotranslational export via its C-terminal ribosome stalling-like motif. This allows for the unfolding of an mRNA stem-loop sequence that shields the ribosome-binding site of cutO, which favors its subsequent translation. Bioinformatic analyses reveal that CutF-like proteins are widely distributed in bacteria and are often located upstream of genes involved in transition metal homeostasis. Our overall findings illustrate a highly conserved control mechanism using the cotranslational export of a protein acting as a sensor to integrate the changing availability of extracellular nutrients into metabolic acclimation. IMPORTANCE Metabolite sensing is a fundamental biological process, and the perception of dynamic changes in the extracellular environment is of paramount importance for the survival of organisms. Bacteria usually adjust their metabolisms to changing environments via transcriptional regulation. Here, using Rhodobacter capsulatus, we describe an alternative translational mechanism that controls the bacterial response to the presence of copper, a toxic micronutrient. This mechanism involves a cotranslationally secreted protein that, in the presence of copper, undergoes a process resembling ribosomal stalling. This allows for the unfolding of a downstream mRNA stem-loop and enables the translation of the adjacent Cu-detoxifying multicopper oxidase. Bioinformatic analyses reveal that such proteins are widespread, suggesting that metabolic sensing using ribosome-arrested nascent secreted proteins acting as sensors may be a common strategy for the integration of environmental signals into metabolic adaptations.
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Abstract
Copper is essential to most living beings but also highly toxic and as such is an important player at the host-pathogen interface. Bacteria have thus developed homeostatic mechanisms to tightly control its intracellular concentration. Known Cu export and import systems are under transcriptional control, whereas posttranscriptional regulatory mechanisms are yet to be characterized. We identified a three-gene operon, bp2923-bfrG-bp2921, downregulated by copper and notably encoding a TonB-dependent transporter in Bordetella pertussis. We show here that the protein encoded by the first gene, which is a member of the DUF2946 protein family, represents a new type of upstream Open Reading Frame (uORF) involved in posttranscriptional regulation of the downstream genes. In the absence of copper, the entire operon is transcribed and translated. Perception of copper by the nascent bp2923-coded protein via its conserved CXXC motif triggers Rho-dependent transcription termination between the first and second genes by relieving translation arrest on a conserved C-terminal RAPP motif. Homologs of bp2923 are widespread in bacterial genomes, where they head operons predicted to participate in copper homeostasis. This work has thus unveiled a new mode of genetic regulation by a transition metal and identified a regulatory function for a member of an uncharacterized family of bacterial proteins that we have named CruR, for copper-responsive upstream regulator.
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Novoa-Aponte L, Argüello JM. Unique underlying principles shaping copper homeostasis networks. J Biol Inorg Chem 2022; 27:509-528. [PMID: 35802193 PMCID: PMC9470648 DOI: 10.1007/s00775-022-01947-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/27/2022] [Indexed: 12/27/2022]
Abstract
Abstract Copper is essential in cells as a cofactor for key redox enzymes. Bacteria have acquired molecular components that sense, uptake, distribute, and expel copper ensuring that cuproenzymes are metallated and steady-state metal levels are maintained. Toward preventing deleterious reactions, proteins bind copper ions with high affinities and transfer the metal via ligand exchange, warranting that copper ions are always complexed. Consequently, the directional copper distribution within cell compartments and across cell membranes requires specific dynamic interactions and metal exchange between cognate holo-apo protein partners. These metal exchange reactions are determined by thermodynamic and kinetics parameters and influenced by mass action. Then, copper distribution can be conceptualized as a molecular system of singular interacting elements that maintain a physiological copper homeostasis. This review focuses on the impact of copper high-affinity binding and exchange reactions on the homeostatic mechanisms, the conceptual models to describe the cell as a homeostatic system, the various molecule functions that contribute to copper homeostasis, and the alternative system architectures responsible for copper homeostasis in model bacteria. Graphical Abstract ![]()
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Affiliation(s)
- Lorena Novoa-Aponte
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.,Genetics and Metabolism Section, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, 20892, USA
| | - José M Argüello
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 60 Prescott St, Worcester, MA, 01605, USA.
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