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Goodall ECA, Isom GL, Rooke JL, Pullela K, Icke C, Yang Z, Boelter G, Jones A, Warner I, Da Costa R, Zhang B, Rae J, Tan WB, Winkle M, Delhaye A, Heinz E, Collet JF, Cunningham AF, Blaskovich MA, Parton RG, Cole JA, Banzhaf M, Chng SS, Vollmer W, Bryant JA, Henderson IR. Loss of YhcB results in dysregulation of coordinated peptidoglycan, LPS and phospholipid synthesis during Escherichia coli cell growth. PLoS Genet 2021; 17:e1009586. [PMID: 34941903 PMCID: PMC8741058 DOI: 10.1371/journal.pgen.1009586] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 01/07/2022] [Accepted: 11/24/2021] [Indexed: 12/13/2022] Open
Abstract
The cell envelope is essential for viability in all domains of life. It retains enzymes and substrates within a confined space while providing a protective barrier to the external environment. Destabilising the envelope of bacterial pathogens is a common strategy employed by antimicrobial treatment. However, even in one of the best studied organisms, Escherichia coli, there remain gaps in our understanding of how the synthesis of the successive layers of the cell envelope are coordinated during growth and cell division. Here, we used a whole-genome phenotypic screen to identify mutants with a defective cell envelope. We report that loss of yhcB, a conserved gene of unknown function, results in loss of envelope stability, increased cell permeability and dysregulated control of cell size. Using whole genome transposon mutagenesis strategies, we report the comprehensive genetic interaction network of yhcB, revealing all genes with a synthetic negative and a synthetic positive relationship. These genes include those previously reported to have a role in cell envelope biogenesis. Surprisingly, we identified genes previously annotated as essential that became non-essential in a ΔyhcB background. Subsequent analyses suggest that YhcB functions at the junction of several envelope biosynthetic pathways coordinating the spatiotemporal growth of the cell, highlighting YhcB as an as yet unexplored antimicrobial target. All life depends on a cell envelope to enclose the chemical reactions that make life possible. But how do cell envelopes grow? How each component of the cell envelope is incorporated into the envelope at the correct amount, in the correct place, and at the correct time, to prevent cell death, has been a long-standing question in bacteriology. Using a unique combination of high throughput chemical genetic screens we identified yhcB, a conserved gene of unknown function, required for the maintenance of cell envelope integrity in Escherichia coli. Loss of YhcB results in aberrant cell size driven by the production of excess membrane phospholipids. Subsequent molecular and biochemical analyses suggest YhcB influences the spatiotemporal biogenesis of LPS, peptidoglycan and membrane phospholipids. Our data indicate YhcB is a key regulator of cell envelope growth in Gram-negative bacteria playing a crucial role in coordinating cell width, elongation, and division to maintain cell envelope integrity.
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Affiliation(s)
- Emily C. A. Goodall
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
- * E-mail: (ECAG); (IRH)
| | - Georgia L. Isom
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jessica L. Rooke
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Karthik Pullela
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Christopher Icke
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Zihao Yang
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Gabriela Boelter
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Alun Jones
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Isabel Warner
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Rochelle Da Costa
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Bing Zhang
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - James Rae
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Wee Boon Tan
- Department of Chemistry, National University of Singapore, Singapore
| | - Matthias Winkle
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Antoine Delhaye
- de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Eva Heinz
- Departments of Vector Biology and Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Adam F. Cunningham
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Mark A. Blaskovich
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
| | - Robert G. Parton
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Australia
| | - Jeff A. Cole
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Manuel Banzhaf
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jack A. Bryant
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Ian R. Henderson
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Australia
- * E-mail: (ECAG); (IRH)
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2
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Mehla J, Liechti G, Morgenstein RM, Caufield JH, Hosseinnia A, Gagarinova A, Phanse S, Goodacre N, Brockett M, Sakhawalkar N, Babu M, Xiao R, Montelione GT, Vorobiev S, den Blaauwen T, Hunt JF, Uetz P. ZapG (YhcB/DUF1043), a novel cell division protein in gamma-proteobacteria linking the Z-ring to septal peptidoglycan synthesis. J Biol Chem 2021; 296:100700. [PMID: 33895137 PMCID: PMC8163987 DOI: 10.1016/j.jbc.2021.100700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/14/2021] [Accepted: 04/21/2021] [Indexed: 01/26/2023] Open
Abstract
YhcB, a poorly understood protein conserved across gamma-proteobacteria, contains a domain of unknown function (DUF1043) and an N-terminal transmembrane domain. Here, we used an integrated approach including X-ray crystallography, genetics, and molecular biology to investigate the function and structure of YhcB. The Escherichia coli yhcB KO strain does not grow at 45 °C and is hypersensitive to cell wall–acting antibiotics, even in the stationary phase. The deletion of yhcB leads to filamentation, abnormal FtsZ ring formation, and aberrant septum development. The Z-ring is essential for the positioning of the septa and the initiation of cell division. We found that YhcB interacts with proteins of the divisome (e.g., FtsI, FtsQ) and elongasome (e.g., RodZ, RodA). Seven of these interactions are also conserved in Yersinia pestis and/or Vibrio cholerae. Furthermore, we mapped the amino acid residues likely involved in the interactions of YhcB with FtsI and RodZ. The 2.8 Å crystal structure of the cytosolic domain of Haemophilus ducreyi YhcB shows a unique tetrameric α-helical coiled-coil structure likely to be involved in linking the Z-ring to the septal peptidoglycan-synthesizing complexes. In summary, YhcB is a conserved and conditionally essential protein that plays a role in cell division and consequently affects envelope biogenesis. Based on these findings, we propose to rename YhcB to ZapG (Z-ring-associated protein G). This study will serve as a starting point for future studies on this protein family and on how cells transit from exponential to stationary survival.
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Affiliation(s)
- Jitender Mehla
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA.
| | - George Liechti
- Department of Microbiology and Immunology, Henry Jackson Foundation, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Randy M Morgenstein
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - J Harry Caufield
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Ali Hosseinnia
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Alla Gagarinova
- Department of Biochemistry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Sadhna Phanse
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Norman Goodacre
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Mary Brockett
- Department of Microbiology and Immunology, Henry Jackson Foundation, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Neha Sakhawalkar
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Rong Xiao
- Nexomics Biosciences Inc., Rocky Hill, New Jersey, USA; Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Gaetano T Montelione
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA; Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Sergey Vorobiev
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA; Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Tanneke den Blaauwen
- Bacterial Cell Biology & Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - John F Hunt
- Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA; Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Peter Uetz
- Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia, USA.
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3
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Coordinate regulation of the expression of SdsR toxin and its downstream pphA gene by RyeA antitoxin in Escherichia coli. Sci Rep 2019; 9:9627. [PMID: 31270363 PMCID: PMC6610125 DOI: 10.1038/s41598-019-45998-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 06/10/2019] [Indexed: 12/17/2022] Open
Abstract
In Escherichia coli, SdsR and RyeA, a unique pair of mutually cis-encoded small RNAs (sRNAs), act as toxin and antitoxin, respectively. SdsR and RyeA expression are reciprocally regulated; however, how each regulates the synthesis of the other remains unclear. Here, we characterized the biosynthesis of the two sRNAs during growth and investigated their coordinate regulation using sdsR and ryeA promoter mutant strains. We found that RyeA transcription occurred even upon entry of cells into the stationary phase, but its apparent expression was restricted to exponentially growing cells because of its degradation by SdsR. Likewise, the appearance of SdsR was delayed owing to its RyeA-mediated degradation. We also found that the sdsR promoter was primarily responsible for transcription of the downstream pphA gene encoding a phosphatase and that pphA mRNA was synthesized by transcriptional read-through over the sdsR terminator. Transcription from the σ70-dependent ryeA promoter inhibited transcription from the σS-dependent sdsR promoter through transcriptional interference. This transcriptional inhibition also downregulated pphA expression, but RyeA itself did not downregulate pphA expression.
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Choi JS, Kim W, Suk S, Park H, Bak G, Yoon J, Lee Y. The small RNA, SdsR, acts as a novel type of toxin in Escherichia coli. RNA Biol 2018; 15:1319-1335. [PMID: 30293519 PMCID: PMC6284582 DOI: 10.1080/15476286.2018.1532252] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/25/2018] [Accepted: 09/29/2018] [Indexed: 01/08/2023] Open
Abstract
Most small noncoding RNAs (sRNAs) are known to base pair with target mRNAs and regulate mRNA stability or translation to trigger various changes in the cell metabolism of Escherichia coli. The SdsR sRNA is expressed specifically during the stationary phase and represses tolC and mutS expression. However, it was not previously known whether the growth-phase-dependent regulation of SdsR is important for cell growth. Here, we ectopically expressed SdsR during the exponential phase and examined cell growth and survival. We found that ectopic expression of SdsR led to a significant and Hfq-dependent cell death with accompanying cell filamentation. This SdsR-driven cell death was alleviated by overexpression of RyeA, an sRNA transcribed on the opposite DNA strand, suggesting that SdsR/RyeA is a novel type of toxin-antitoxin (T/A) system in which both the toxin and the antitoxin are sRNAs. We defined the minimal region required for the SdsR-driven cell death. We also performed RNA-seq analysis and identified 209 genes whose expression levels were altered by more than two-fold following pulse expression of ectopic SdsR at exponential phase. Finally, we found that that the observed SdsR-driven cell death was mainly caused by the SdsR-mediated repression of yhcB, which encodes an inner membrane protein.
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Affiliation(s)
| | | | - Shinae Suk
- Department of Chemistry, KAIST, Daejeon, Korea
| | | | - Geunu Bak
- Department of Chemistry, KAIST, Daejeon, Korea
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5
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Diéguez-Casal E, Freixeiro P, Costoya L, Criado MT, Ferreirós C, Sánchez S. High resolution clear native electrophoresis is a good alternative to blue native electrophoresis for the characterization of the Escherichia coli membrane complexes. J Microbiol Methods 2014; 102:45-54. [PMID: 24845470 DOI: 10.1016/j.mimet.2014.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 05/09/2014] [Accepted: 05/09/2014] [Indexed: 10/25/2022]
Abstract
Blue native electrophoresis (BNE) has become the most popular method for the global analysis of membrane protein complexes. Although it has been shown to be very useful for that purpose, it can produce the dissociation of complexes with weak interactions and, due to the use of Coomassie Brilliant Blue, does not allow the subsequent application of fluorimetric and/or enzymatic techniques. Recently, we have successfully used the high resolution clear native electrophoresis (hrCNE) for the analysis of Neisseria meningitidis outer membrane porin complexes. The aim of this study was to determine the composition of the complexome of the Escherichia coli envelope by using hrCNE and to compare our results with those previously obtained using BNE. The bidimensional electrophoresis approaches used, hrCN/hrCNE and hrCN/SDS-PAGE, coupled to mass spectrometry allowed a detailed analysis of the complexome of E. coli membranes. For the first time, the three subunits of the formate dehydrogenase FDH-O were identified forming a single complex and hrCNE also allowed the identification of both the HflK and HflC proteins as components of the HflA complex. This technique also allowed us to suggest a relationship between OmpF and DLDH and, although OmpA is considered to be monomeric in vivo, we found this protein structured as homodimers. Thus hrCNE provides a good tool for future analyses of bacterial membrane proteins and complexes and is an important alternative to the commonly used BNE.
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Affiliation(s)
- Ernesto Diéguez-Casal
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Vida, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Paula Freixeiro
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Vida, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Liliana Costoya
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Vida, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - M Teresa Criado
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Vida, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Carlos Ferreirós
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Vida, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Sandra Sánchez
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Campus Vida, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
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6
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Li G, Hamamoto K, Kitakawa M. Inner Membrane Protein YhcB Interacts with RodZ Involved in Cell Shape Maintenance in Escherichia coli. ISRN MOLECULAR BIOLOGY 2012; 2012:304021. [PMID: 27335665 PMCID: PMC4890886 DOI: 10.5402/2012/304021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 07/22/2012] [Indexed: 12/03/2022]
Abstract
Depletion of YhcB, an inner membrane protein of Escherichia coli, inhibited the growth of rodZ deletion mutant showing that the loss of both YhcB and RodZ is synthetically lethal. Furthermore, YhcB was demonstrated to interact with RodZ as well as several other proteins involved in cell shape maintenance and an inner membrane protein YciS of unknown function, using bacterial two-hybrid system. These observations seem to indicate that YhcB is involved in the biogenesis of cell envelope and the maintenance of cell shape together with RodZ.
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Affiliation(s)
- Gaochi Li
- Department of Biology, Faculty of Science, Kobe University, Rokko, Kobe, Hyogo 657-8501, Japan
| | - Kentaro Hamamoto
- Department of Biology, Faculty of Science, Kobe University, Rokko, Kobe, Hyogo 657-8501, Japan
| | - Madoka Kitakawa
- Department of Biology, Faculty of Science, Kobe University, Rokko, Kobe, Hyogo 657-8501, Japan
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Borisov VB, Gennis RB, Hemp J, Verkhovsky MI. The cytochrome bd respiratory oxygen reductases. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1807:1398-413. [PMID: 21756872 PMCID: PMC3171616 DOI: 10.1016/j.bbabio.2011.06.016] [Citation(s) in RCA: 374] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 06/23/2011] [Accepted: 06/24/2011] [Indexed: 01/03/2023]
Abstract
Cytochrome bd is a respiratory quinol: O₂ oxidoreductase found in many prokaryotes, including a number of pathogens. The main bioenergetic function of the enzyme is the production of a proton motive force by the vectorial charge transfer of protons. The sequences of cytochromes bd are not homologous to those of the other respiratory oxygen reductases, i.e., the heme-copper oxygen reductases or alternative oxidases (AOX). Generally, cytochromes bd are noteworthy for their high affinity for O₂ and resistance to inhibition by cyanide. In E. coli, for example, cytochrome bd (specifically, cytochrome bd-I) is expressed under O₂-limited conditions. Among the members of the bd-family are the so-called cyanide-insensitive quinol oxidases (CIO) which often have a low content of the eponymous heme d but, instead, have heme b in place of heme d in at least a majority of the enzyme population. However, at this point, no sequence motif has been identified to distinguish cytochrome bd (with a stoichiometric complement of heme d) from an enzyme designated as CIO. Members of the bd-family can be subdivided into those which contain either a long or a short hydrophilic connection between transmembrane helices 6 and 7 in subunit I, designated as the Q-loop. However, it is not clear whether there is a functional consequence of this difference. This review summarizes current knowledge on the physiological functions, genetics, structural and catalytic properties of cytochromes bd. Included in this review are descriptions of the intermediates of the catalytic cycle, the proposed site for the reduction of O₂, evidence for a proton channel connecting this active site to the bacterial cytoplasm, and the molecular mechanism by which a membrane potential is generated.
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Affiliation(s)
- Vitaliy B Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russian Federation.
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Molecular strategy for survival at a critical high temperature in Eschierichia coli. PLoS One 2011; 6:e20063. [PMID: 21695201 PMCID: PMC3112155 DOI: 10.1371/journal.pone.0020063] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 04/12/2011] [Indexed: 01/19/2023] Open
Abstract
The molecular mechanism supporting survival at a critical high temperature (CHT) in Escherichia coli was investigated. Genome-wide screening with a single-gene knockout library provided a list of genes indispensable for growth at 47°C, called thermotolerant genes. Genes for which expression was affected by exposure to CHT were identified by DNA chip analysis. Unexpectedly, the former contents did not overlap with the latter except for dnaJ and dnaK, indicating that a specific set of non-heat shock genes is required for the organism to survive under such a severe condition. More than half of the mutants of the thermotolerant genes were found to be sensitive to H2O2 at 30°C, suggesting that the mechanism of thermotolerance partially overlaps with that of oxidative stress resistance. Their encoded enzymes or proteins are related to outer membrane organization, DNA double-strand break repair, tRNA modification, protein quality control, translation control or cell division. DNA chip analyses of essential genes suggest that many of the genes encoding ribosomal proteins are down-regulated at CHT. Bioinformatics analysis and comparison with the genomic information of other microbes suggest that E. coli possesses several systems for survival at CHT. This analysis allows us to speculate that a lipopolysaccharide biosynthesis system for outer membrane organization and a sulfur-relay system for tRNA modification have been acquired by horizontal gene transfer.
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Mogi T. Probing the haem d-binding site in cytochrome bd quinol oxidase by site-directed mutagenesis. J Biochem 2009; 145:763-70. [DOI: 10.1093/jb/mvp033] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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10
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Mogi T. Effects of replacement of low-spin haem b by haem O on Escherichia coli cytochromes bo and bd quinol oxidases. J Biochem 2009; 145:599-607. [PMID: 19174546 DOI: 10.1093/jb/mvp015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cytochromes bo and bd are terminal ubiquinol oxidases in the aerobic respiratory chain of Escherichia coli and generate proton motive force across the membrane. To probe roles of haem species in the oxidation of quinols, intramolecular electron transfer and the dioxygen reduction, we replaced b-haems with haem O by using the haem O synthase-overproducing system, which can accumulate haem O in cytoplasmic membranes. Characterizations of spectroscopic properties of cytochromes bo and bd isolated from BL21 (DE3)/pLysS and BL21 (DE3)/pLysS/pTTQ18-cyoE after 4 h of the aerobic induction of haem O synthase (CyoE) showed the specific incorporation of haem O into the low-spin haem-binding site in both oxidases. We found that the resultant haem oo- and obd-type oxidase severely reduced the ubiquinol-1 oxidase activity due to the perturbations of the quinol oxidation site. Our observations suggest that haem B is required at the low-spin haem site for the oxidation of quinols by cytochromes bo and bd.
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Affiliation(s)
- Tatsushi Mogi
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Tokyo, Japan.
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Lenn T, Leake MC, Mullineaux CW. Clustering and dynamics of cytochromebd-I complexes in theEscherichia coliplasma membranein vivo. Mol Microbiol 2008; 70:1397-407. [DOI: 10.1111/j.1365-2958.2008.06486.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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