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Harris L, Fondrie WE, Oh S, Noble WS. Evaluating Proteomics Imputation Methods with Improved Criteria. J Proteome Res 2023; 22:3427-3438. [PMID: 37861703 PMCID: PMC10949645 DOI: 10.1021/acs.jproteome.3c00205] [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] [Indexed: 10/21/2023]
Abstract
Quantitative measurements produced by tandem mass spectrometry proteomics experiments typically contain a large proportion of missing values. Missing values hinder reproducibility, reduce statistical power, and make it difficult to compare across samples or experiments. Although many methods exist for imputing missing values, in practice, the most commonly used methods are among the worst performing. Furthermore, previous benchmarking studies have focused on relatively simple measurements of error such as the mean-squared error between imputed and held-out values. Here we evaluate the performance of commonly used imputation methods using three practical, "downstream-centric" criteria. These criteria measure the ability to identify differentially expressed peptides, generate new quantitative peptides, and improve the peptide lower limit of quantification. Our evaluation comprises several experiment types and acquisition strategies, including data-dependent and data-independent acquisition. We find that imputation does not necessarily improve the ability to identify differentially expressed peptides but that it can identify new quantitative peptides and improve the peptide lower limit of quantification. We find that MissForest is generally the best performing method per our downstream-centric criteria. We also argue that existing imputation methods do not properly account for the variance of peptide quantifications and highlight the need for methods that do.
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Affiliation(s)
- Lincoln Harris
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, United States
| | | | - Sewoong Oh
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, Washington 98195, United States
| | - William S Noble
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, United States
- Paul G. Allen School of Computer Science and Engineering, University of Washington, Seattle, Washington 98195, United States
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2
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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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3
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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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Dey P, Malik A, Singh DK, Haange SB, von Bergen M, Jehmlich N. Insight Into the Molecular Mechanisms Underpinning the Mycoremediation of Multiple Metals by Proteomic Technique. Front Microbiol 2022; 13:872576. [PMID: 35756008 PMCID: PMC9221998 DOI: 10.3389/fmicb.2022.872576] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
We investigated the fungus Aspergillus fumigatus PD-18 responses when subjected to the multimetal combination (Total Cr, Cd2+, Cu2+, Ni2+, Pb2+, and Zn2+) in synthetic composite media. To understand how multimetal stress impacts fungal cells at the molecular level, the cellular response of A. fumigatus PD-18 to 30 mg/L multimetal stress (5 mg/L of each heavy metal) was determined by proteomics. The comparative fungal proteomics displayed the remarkable inherent intracellular and extracellular mechanism of metal resistance and tolerance potential of A. fumigatus PD-18. This study reported 2,238 proteins of which 434 proteins were exclusively expressed in multimetal extracts. The most predominant functional class expressed was for cellular processing and signaling. The type of proteins and the number of proteins that were upregulated due to various stress tolerance mechanisms were post-translational modification, protein turnover, and chaperones (42); translation, ribosomal structure, and biogenesis (60); and intracellular trafficking, secretion, and vesicular transport (18). In addition, free radical scavenging antioxidant proteins, such as superoxide dismutase, were upregulated upto 3.45-fold and transporter systems, such as protein transport (SEC31), upto 3.31-fold to combat the oxidative stress caused by the multiple metals. Also, protein–protein interaction network analysis revealed that cytochrome c oxidase and 60S ribosomal protein played key roles to detoxify the multimetal. To the best of our knowledge, this study of A. fumigatus PD-18 provides valuable insights toward the growing research in comprehending the metal microbe interactions in the presence of multimetal. This will facilitate in development of novel molecular markers for contaminant bioremediation.
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Affiliation(s)
- Priyadarshini Dey
- Applied Microbiology Lab, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research, Helmholtz Association of German Research Centres (HZ), Leipzig, Germany
- Department of Biotechnology, MS Ramaiah Institute of Technology, Bengaluru, India
| | - Anushree Malik
- Applied Microbiology Lab, Centre for Rural Development and Technology, Indian Institute of Technology Delhi, New Delhi, India
| | - Dileep Kumar Singh
- Department of Zoology, Faculty of Science, University of Delhi, New Delhi, India
| | - Sven-Bastiaan Haange
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research, Helmholtz Association of German Research Centres (HZ), Leipzig, Germany
| | - Martin von Bergen
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research, Helmholtz Association of German Research Centres (HZ), Leipzig, Germany
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Leipzig, Germany
- German Centre for Integrative Biodiversity, Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Nico Jehmlich
- Department of Molecular Systems Biology, Helmholtz Centre for Environmental Research, Helmholtz Association of German Research Centres (HZ), Leipzig, Germany
- *Correspondence: Nico Jehmlich,
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Durand A, Fouesnard M, Bourbon ML, Steunou AS, Lojou E, Dorlet P, Ouchane S. A periplasmic cupredoxin with a green CuT1.5 center is involved in bacterial copper tolerance. Metallomics 2021; 13:6428408. [PMID: 34791351 DOI: 10.1093/mtomcs/mfab067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 11/05/2021] [Indexed: 12/26/2022]
Abstract
The importance of copper resistance pathways in pathogenic bacteria is now well recognized, since macrophages use copper to fight bacterial infections. Additionally, considering the increase of antibiotic resistance, growing attention is given to the antimicrobial properties of copper. It is of primary importance to understand how bacteria deal with copper. The Cu-resistant cuproprotein CopI is present in many human bacterial pathogens and environmental bacteria and crucial under microaerobiosis (conditions for most pathogens to thrive within their host). Hence, understanding its mechanism of function is essential. CopI proteins share conserved histidine, cysteine, and methionine residues that could be ligands for different copper binding sites, among which the cupredoxin center could be involved in the protein function. Here, we demonstrated that Vibrio cholerae and Pseudomonas aeruginosa CopI restore the Cu-resistant phenotype in the Rubrivivax gelatinosus ΔcopI mutant. We identified that Cys125 (ligand in the cupredoxin center) and conserved histidines and methionines are essential for R. gelatinosus CopI (RgCopI) function. We also performed spectroscopic analyses of the purified RgCopI protein and showed that it is a green cupredoxin able to bind a maximum of three Cu(II) ions: (i) a green Cu site (CuT1.5), (ii) a type 2 Cu binding site (T2) located in the N-terminal region, and (iii) a third site with a yet unidentified location. CopI is therefore one member of the poorly described CuT1.5 center cupredoxin family. It is unique, since it is a single-domain cupredoxin with more than one Cu site involved in Cu resistance.
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Affiliation(s)
- Anne Durand
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Mélanie Fouesnard
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Marie-Line Bourbon
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Anne-Soisig Steunou
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | | | - Pierre Dorlet
- CNRS, Aix-Marseille Université, BIP, IMM, Marseille, France
| | - Soufian Ouchane
- CEA, CNRS, Université Paris-Saclay, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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6
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Andrei A, Di Renzo MA, Öztürk Y, Meisner A, Daum N, Frank F, Rauch J, Daldal F, Andrade SLA, Koch HG. The CopA2-Type P 1B-Type ATPase CcoI Serves as Central Hub for cbb 3-Type Cytochrome Oxidase Biogenesis. Front Microbiol 2021; 12:712465. [PMID: 34589071 PMCID: PMC8475189 DOI: 10.3389/fmicb.2021.712465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Copper (Cu)-transporting P1B-type ATPases are ubiquitous metal transporters and crucial for maintaining Cu homeostasis in all domains of life. In bacteria, the P1B-type ATPase CopA is required for Cu-detoxification and exports excess Cu(I) in an ATP-dependent reaction from the cytosol into the periplasm. CopA is a member of the CopA1-type ATPase family and has been biochemically and structurally characterized in detail. In contrast, less is known about members of the CopA2-type ATPase family, which are predicted to transport Cu(I) into the periplasm for cuproprotein maturation. One example is CcoI, which is required for the maturation of cbb 3-type cytochrome oxidase (cbb 3-Cox) in different species. Here, we reconstituted purified CcoI of Rhodobacter capsulatus into liposomes and determined Cu transport using solid-supported membrane electrophysiology. The data demonstrate ATP-dependent Cu(I) translocation by CcoI, while no transport is observed in the presence of a non-hydrolysable ATP analog. CcoI contains two cytosolically exposed N-terminal metal binding sites (N-MBSs), which are both important, but not essential for Cu delivery to cbb 3-Cox. CcoI and cbb 3-Cox activity assays in the presence of different Cu concentrations suggest that the glutaredoxin-like N-MBS1 is primarily involved in regulating the ATPase activity of CcoI, while the CopZ-like N-MBS2 is involved in Cu(I) acquisition. The interaction of CcoI with periplasmic Cu chaperones was analyzed by genetically fusing CcoI to the chaperone SenC. The CcoI-SenC fusion protein was fully functional in vivo and sufficient to provide Cu for cbb 3-Cox maturation. In summary, our data demonstrate that CcoI provides the link between the cytosolic and periplasmic Cu chaperone networks during cbb 3-Cox assembly.
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Affiliation(s)
- Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Maria Agostina Di Renzo
- Institute for Biochemistry, Faculty of Chemistry and Pharmacy, Albert-Ludwigs-University Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, Germany.,Faculty of Chemistry and Pharmacy, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Alexandra Meisner
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Noel Daum
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Fabian Frank
- Institute for Biochemistry, Faculty of Chemistry and Pharmacy, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Susana L A Andrade
- Institute for Biochemistry, Faculty of Chemistry and Pharmacy, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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7
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Öztürk Y, Blaby-Haas CE, Daum N, Andrei A, Rauch J, Daldal F, Koch HG. Maturation of Rhodobacter capsulatus Multicopper Oxidase CutO Depends on the CopA Copper Efflux Pathway and Requires the cutF Product. Front Microbiol 2021; 12:720644. [PMID: 34566924 PMCID: PMC8456105 DOI: 10.3389/fmicb.2021.720644] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/18/2021] [Indexed: 11/15/2022] Open
Abstract
Copper (Cu) is an essential cofactor required for redox enzymes in all domains of life. Because of its toxicity, tightly controlled mechanisms ensure Cu delivery for cuproenzyme biogenesis and simultaneously protect cells against toxic Cu. Many Gram-negative bacteria contain extracytoplasmic multicopper oxidases (MCOs), which are involved in periplasmic Cu detoxification. MCOs are unique cuproenzymes because their catalytic center contains multiple Cu atoms, which are required for the oxidation of Cu1+ to the less toxic Cu2+. Hence, Cu is both substrate and essential cofactor of MCOs. Here, we investigated the maturation of Rhodobacter capsulatus MCO CutO and its role in periplasmic Cu detoxification. A survey of CutO activity of R. capsulatus mutants with known defects in Cu homeostasis and in the maturation of the cuproprotein cbb 3-type cytochrome oxidase (cbb 3-Cox) was performed. This revealed that CutO activity is largely independent of the Cu-delivery pathway for cbb 3-Cox biogenesis, except for the cupric reductase CcoG, which is required for full CutO activity. The most pronounced decrease of CutO activity was observed with strains lacking the cytoplasmic Cu chaperone CopZ, or the Cu-exporting ATPase CopA, indicating that CutO maturation is linked to the CopZ-CopA mediated Cu-detoxification pathway. Our data demonstrate that CutO is important for cellular Cu resistance under both aerobic and anaerobic growth conditions. CutO is encoded in the cutFOG operon, but only CutF, and not CutG, is essential for CutO activity. No CutO activity is detectable when cutF or its putative Cu-binding motif are mutated, suggesting that the cutF product serves as a Cu-binding component required for active CutO production. Bioinformatic analyses of CutF-like proteins support their widespread roles as putative Cu-binding proteins for several Cu-relay pathways. Our overall findings show that the cytoplasmic CopZ-CopA dependent Cu detoxification pathway contributes to providing Cu to CutO maturation, a process that strictly relies on cutF.
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Affiliation(s)
- Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Crysten E. Blaby-Haas
- Biology Department, Brookhaven National Laboratory, Upton, NY, United States
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, United States
| | - Noel Daum
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
- Fakultät für Biologie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
| | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA, United States
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany
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Cryo-EM structures of engineered active bc 1-cbb 3 type CIII 2CIV super-complexes and electronic communication between the complexes. Nat Commun 2021; 12:929. [PMID: 33568648 PMCID: PMC7876108 DOI: 10.1038/s41467-021-21051-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 01/06/2021] [Indexed: 01/30/2023] Open
Abstract
Respiratory electron transport complexes are organized as individual entities or combined as large supercomplexes (SC). Gram-negative bacteria deploy a mitochondrial-like cytochrome (cyt) bc1 (Complex III, CIII2), and may have specific cbb3-type cyt c oxidases (Complex IV, CIV) instead of the canonical aa3-type CIV. Electron transfer between these complexes is mediated by soluble (c2) and membrane-anchored (cy) cyts. Here, we report the structure of an engineered bc1-cbb3 type SC (CIII2CIV, 5.2 Å resolution) and three conformers of native CIII2 (3.3 Å resolution). The SC is active in vivo and in vitro, contains all catalytic subunits and cofactors, and two extra transmembrane helices attributed to cyt cy and the assembly factor CcoH. The cyt cy is integral to SC, its cyt domain is mobile and it conveys electrons to CIV differently than cyt c2. The successful production of a native-like functional SC and determination of its structure illustrate the characteristics of membrane-confined and membrane-external respiratory electron transport pathways in Gram-negative bacteria.
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9
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Andrei A, Öztürk Y, Khalfaoui-Hassani B, Rauch J, Marckmann D, Trasnea PI, Daldal F, Koch HG. Cu Homeostasis in Bacteria: The Ins and Outs. MEMBRANES 2020; 10:E242. [PMID: 32962054 PMCID: PMC7558416 DOI: 10.3390/membranes10090242] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/16/2022]
Abstract
Copper (Cu) is an essential trace element for all living organisms and used as cofactor in key enzymes of important biological processes, such as aerobic respiration or superoxide dismutation. However, due to its toxicity, cells have developed elaborate mechanisms for Cu homeostasis, which balance Cu supply for cuproprotein biogenesis with the need to remove excess Cu. This review summarizes our current knowledge on bacterial Cu homeostasis with a focus on Gram-negative bacteria and describes the multiple strategies that bacteria use for uptake, storage and export of Cu. We furthermore describe general mechanistic principles that aid the bacterial response to toxic Cu concentrations and illustrate dedicated Cu relay systems that facilitate Cu delivery for cuproenzyme biogenesis. Progress in understanding how bacteria avoid Cu poisoning while maintaining a certain Cu quota for cell proliferation is of particular importance for microbial pathogens because Cu is utilized by the host immune system for attenuating pathogen survival in host cells.
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Affiliation(s)
- Andreea Andrei
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
- Fakultät für Biologie, Albert-Ludwigs Universität Freiburg; Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Yavuz Öztürk
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Juna Rauch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | - Dorian Marckmann
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
| | | | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Medizinische Fakultät, Albert-Ludwigs Universität Freiburg; Stefan Meier Str. 17, 79104 Freiburg, Germany; (A.A.); (Y.O.); (J.R.); (D.M.)
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