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Takayesu A, Mahoney BJ, Goring AK, Jessup T, Ogorzalek Loo RR, Loo JA, Clubb RT. Insight into the autoproteolysis mechanism of the RsgI9 anti-σ factor from Clostridium thermocellum. Proteins 2024; 92:946-958. [PMID: 38597224 PMCID: PMC11222046 DOI: 10.1002/prot.26690] [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: 11/06/2023] [Revised: 03/19/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024]
Abstract
Clostridium thermocellum is a potential microbial platform to convert abundant plant biomass to biofuels and other renewable chemicals. It efficiently degrades lignocellulosic biomass using a surface displayed cellulosome, a megadalton sized multienzyme containing complex. The enzymatic composition and architecture of the cellulosome is controlled by several transmembrane biomass-sensing RsgI-type anti-σ factors. Recent studies suggest that these factors transduce signals from the cell surface via a conserved RsgI extracellular (CRE) domain (also called a periplasmic domain) that undergoes autoproteolysis through an incompletely understood mechanism. Here we report the structure of the autoproteolyzed CRE domain from the C. thermocellum RsgI9 anti-σ factor, revealing that the cleaved fragments forming this domain associate to form a stable α/β/α sandwich fold. Based on AlphaFold2 modeling, molecular dynamics simulations, and tandem mass spectrometry, we propose that a conserved Asn-Pro bond in RsgI9 autoproteolyzes via a succinimide intermediate whose formation is promoted by a conserved hydrogen bond network holding the scissile peptide bond in a strained conformation. As other RsgI anti-σ factors share sequence homology to RsgI9, they likely autoproteolyze through a similar mechanism.
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Affiliation(s)
- Allen Takayesu
- Department of Chemistry and Biochemistry, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- UCLA-DOE Institute of Genomics and Proteomics, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
| | - Brendan J. Mahoney
- UCLA-DOE Institute of Genomics and Proteomics, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- Molecular Biology Institute. University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
| | - Andrew K. Goring
- Department of Chemistry and Biochemistry, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- UCLA-DOE Institute of Genomics and Proteomics, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
| | - Tobie Jessup
- Department of Chemistry and Biochemistry, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
| | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- Molecular Biology Institute. University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- UCLA-DOE Institute of Genomics and Proteomics, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- Molecular Biology Institute. University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- UCLA-DOE Institute of Genomics and Proteomics, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
- Molecular Biology Institute. University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095, USA
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2
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de Assis Noman G, Lacerda de Moura BE, Vieira ML. Leptospiral LipL45 lipoprotein undergoes processing and shares structural similarities with bacterial sigma regulators. Biochem Biophys Res Commun 2024; 717:150057. [PMID: 38718568 DOI: 10.1016/j.bbrc.2024.150057] [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: 02/21/2024] [Revised: 04/23/2024] [Accepted: 05/03/2024] [Indexed: 05/21/2024]
Abstract
Leptospirosis is a widespread zoonotic infectious disease of human and veterinary concern caused by pathogenic spirochetes of the genus Leptospira. To date, little progress towards understanding leptospiral pathogenesis and identification of virulence factors has been made, which is the main bottleneck for developing effective measures against the disease. Some leptospiral proteins, including LipL32, Lig proteins, LipL45, and LipL21, are being considered as potential virulence factors or vaccine candidates. However, their function remains to be established. LipL45 is the most expressed membrane lipoprotein in leptospires, upregulated when the bacteria are transferred to temperatures resembling the host, expressed during infection, suppressed after culture attenuation, and known to suffer processing in vivo and in vitro, generating fragments. Based on body of evidence, we hypothesized that the LipL45 processing might occur by an auto-cleavage event, deriving two fragments. The results presented here, based on bioinformatics, structure modeling analysis, and experimental data, corroborate that LipL45 processing probably includes a self-catalyzed non-proteolytic event and suggest the participation of LipL45 in cell-surface signaling pathways, as the protein shares structural similarities with bacterial sigma regulators. Our data indicate that LipL45 might play an important role in response to environmental conditions, with possible function in the adaptation to the host.
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Affiliation(s)
- Gabriel de Assis Noman
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil; Programa de Pós-graduação Em Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.
| | | | - Mônica Larucci Vieira
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil; Programa de Pós-graduação Em Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.
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3
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Otero-Asman JR, Sánchez-Jiménez A, Bastiaansen KC, Wettstadt S, Civantos C, García-Puente A, Bitter W, Llamas MA. The Prc and CtpA proteases modulate cell-surface signaling activity and virulence in Pseudomonas aeruginosa. iScience 2023; 26:107216. [PMID: 37534181 PMCID: PMC10392083 DOI: 10.1016/j.isci.2023.107216] [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: 04/17/2023] [Revised: 05/17/2023] [Accepted: 06/22/2023] [Indexed: 08/04/2023] Open
Abstract
Cell-surface signaling (CSS) is a signal transfer system of Gram-negative bacteria that produces the activation of an extracytoplasmic function σ factor (σECF) in the cytosol in response to an extracellular signal. Activation requires the regulated and sequential proteolysis of the σECF-associated anti-σ factor, and the function of the Prc and RseP proteases. In this work, we have identified another protease that modulates CSS activity, namely the periplasmic carboxyl-terminal processing protease CtpA. CtpA functions upstream of Prc in the proteolytic cascade and seems to prevent the Prc-mediated proteolysis of the CSS anti-σ factor. Importantly, using zebrafish embryos and the A549 lung epithelial cell line as hosts, we show that mutants in the rseP and ctpA proteases of the human pathogen Pseudomonas aeruginosa are considerably attenuated in virulence while the prc mutation increases virulence likely by enhancing the production of membrane vesicles.
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Affiliation(s)
- Joaquín R. Otero-Asman
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Ana Sánchez-Jiménez
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Karlijn C. Bastiaansen
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
- Department of Medical Microbiology and Infection Control, Amsterdam University medical centres, location VU University, 1081 HV Amsterdam, The Netherlands
| | - Sarah Wettstadt
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Cristina Civantos
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Alicia García-Puente
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, Amsterdam University medical centres, location VU University, 1081 HV Amsterdam, The Netherlands
| | - María A. Llamas
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
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4
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Chen C, Dong S, Yu Z, Qiao Y, Li J, Ding X, Li R, Lin J, Bayer EA, Liu YJ, Cui Q, Feng Y. Essential autoproteolysis of bacterial anti-σ factor RsgI for transmembrane signal transduction. SCIENCE ADVANCES 2023; 9:eadg4846. [PMID: 37418529 PMCID: PMC10328401 DOI: 10.1126/sciadv.adg4846] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/06/2023] [Indexed: 07/09/2023]
Abstract
Autoproteolysis has been discovered to play key roles in various biological processes, but functional autoproteolysis has been rarely reported for transmembrane signaling in prokaryotes. In this study, an autoproteolytic effect was discovered in the conserved periplasmic domain of anti-σ factor RsgIs from Clostridium thermocellum, which was found to transmit extracellular polysaccharide-sensing signals into cells for regulation of the cellulosome system, a polysaccharide-degrading multienzyme complex. Crystal and NMR structures of periplasmic domains from three RsgIs demonstrated that they are different from all known proteins that undergo autoproteolysis. The RsgI-based autocleavage site was located at a conserved Asn-Pro motif between the β1 and β2 strands in the periplasmic domain. This cleavage was demonstrated to be essential for subsequent regulated intramembrane proteolysis to activate the cognate SigI, in a manner similar to that of autoproteolysis-dependent activation of eukaryotic adhesion G protein-coupled receptors. These results indicate the presence of a unique prevalent type of autoproteolytic phenomenon in bacteria for signal transduction.
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Affiliation(s)
- Chao Chen
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sheng Dong
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhaoli Yu
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai 200438, China
| | - Yichen Qiao
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jie Li
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoke Ding
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Renmin Li
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai 200438, China
| | - Edward A. Bayer
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department of Life Sciences and The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 8499000, Israel
| | - Ya-Jun Liu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Chan DCK, Josts I, Koteva K, Wright GD, Tidow H, Burrows LL. Interactions of TonB-dependent transporter FoxA with siderophores and antibiotics that affect binding, uptake, and signal transduction. Proc Natl Acad Sci U S A 2023; 120:e2221253120. [PMID: 37043535 PMCID: PMC10120069 DOI: 10.1073/pnas.2221253120] [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: 12/14/2022] [Accepted: 03/07/2023] [Indexed: 04/13/2023] Open
Abstract
The outer membrane of gram-negative bacteria prevents many antibiotics from reaching intracellular targets. However, some antimicrobials can take advantage of iron import transporters to cross this barrier. We showed previously that the thiopeptide antibiotic thiocillin exploits the nocardamine xenosiderophore transporter, FoxA, of the opportunistic pathogen Pseudomonas aeruginosa for uptake. Here, we show that FoxA also transports the xenosiderophore bisucaberin and describe at 2.5 Å resolution the crystal structure of bisucaberin bound to FoxA. Bisucaberin is distinct from other siderophores because it forms a 3:2 rather than 1:1 siderophore-iron complex. Mutations in a single extracellular loop of FoxA differentially affected nocardamine, thiocillin, and bisucaberin binding, uptake, and signal transduction. These results show that in addition to modulating ligand binding, the extracellular loops of siderophore transporters are of fundamental importance for controlling ligand uptake and its regulatory consequences, which have implications for the development of siderophore-antibiotic conjugates to treat difficult infections.
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Affiliation(s)
- Derek C. K. Chan
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
| | - Inokentijs Josts
- The Hamburg Advanced Research Center for Bioorganic Chemistry, Hamburg22761, Germany
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg22761, Germany
| | - Kalinka Koteva
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
| | - Gerard D. Wright
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
| | - Henning Tidow
- The Hamburg Advanced Research Center for Bioorganic Chemistry, Hamburg22761, Germany
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg22761, Germany
| | - Lori L. Burrows
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
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Braun V, Hartmann MD, Hantke K. Transcription regulation of iron carrier transport genes by ECF sigma factors through signaling from the cell surface into the cytoplasm. FEMS Microbiol Rev 2022; 46:6524835. [PMID: 35138377 PMCID: PMC9249621 DOI: 10.1093/femsre/fuac010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 01/26/2022] [Accepted: 02/07/2022] [Indexed: 12/02/2022] Open
Abstract
Bacteria are usually iron-deficient because the Fe3+ in their environment is insoluble or is incorporated into proteins. To overcome their natural iron limitation, bacteria have developed sophisticated iron transport and regulation systems. In gram-negative bacteria, these include iron carriers, such as citrate, siderophores, and heme, which when loaded with Fe3+ adsorb with high specificity and affinity to outer membrane proteins. Binding of the iron carriers to the cell surface elicits a signal that initiates transcription of iron carrier transport and synthesis genes, referred to as “cell surface signaling”. Transcriptional regulation is not coupled to transport. Outer membrane proteins with signaling functions contain an additional N-terminal domain that in the periplasm makes contact with an anti-sigma factor regulatory protein that extends from the outer membrane into the cytoplasm. Binding of the iron carriers to the outer membrane receptors elicits proteolysis of the anti-sigma factor by two different proteases, Prc in the periplasm, and RseP in the cytoplasmic membrane, inactivates the anti-sigma function or results in the generation of an N-terminal peptide of ∼50 residues with pro-sigma activity yielding an active extracytoplasmic function (ECF) sigma factor. Signal recognition and signal transmission into the cytoplasm is discussed herein.
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Affiliation(s)
- Volkmar Braun
- Max Planck Institute for Biology, Department of Protein Evolution, Max Planck Ring 5, 72076 Tübingen, Germany
| | - Marcus D Hartmann
- Max Planck Institute for Biology, Department of Protein Evolution, Max Planck Ring 5, 72076 Tübingen, Germany
| | - Klaus Hantke
- IMIT Institute, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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Li X, Liu H, Yang W, Sheng H, Wang F, Harindintwali JD, Herath HMSK, Zhang Y. Humic acid enhanced pyrene degradation by Mycobacterium sp. NJS-1. CHEMOSPHERE 2022; 288:132613. [PMID: 34678349 DOI: 10.1016/j.chemosphere.2021.132613] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 10/04/2021] [Accepted: 10/17/2021] [Indexed: 06/13/2023]
Abstract
The search for nature-based tools to enhance bioremediation is essential for the sustainable restoration of contaminated ecosystems. Humic acid (HA) is an important component of organic matter in soil and water, but its effect on the microbial degradation of organic pollutants remains unclear. In this study, the biodegradation of pyrene by Mycobacterium sp. NJS-1 with and without HA was investigated. Only around 10.5% of pyrene was biodegraded in the pyrene treatment alone, whereas the addition of HA significantly enhanced biodegradation to the point where over 90% of pyrene was biodegraded. The production of 4,5-dihydropyrene-4,5-diol and phenanthrene-3,4-diol indicated the metabolic pathway via attacking of 4,5-positions of pyrene. Interestingly, 1,2-dimethoxypyrene was detected with the addition of HA, suggesting that HA induced a new ring-opening pathway involving the attack on the 1,2-positions of pyrene. The addition of HA first induced protein self-cleavage behavior with a significant increase in phenylalanine, tyrosine, and tryptophan containing large numbers of COO- groups. Furthermore, it altered the intracellular and extracellular ultrastructure of bacterial cells, promoting their growth in size and number as well as reducing the space between them. Overall, HA increased the ring-opening positions of pyrene and facilitated its interaction with bacterial cells, thus improving its biodegradability. Building upon the findings of this study to further research is conducive to the sustainable solution of environmental pollution.
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Affiliation(s)
- Xiaoning Li
- Nanjing Normal University Center for Analysis and Testing, College of Life Sciences, School of Chemistry and Materials Science, Nanjing, 210046, China
| | - Hailong Liu
- Nanjing Normal University Center for Analysis and Testing, College of Life Sciences, School of Chemistry and Materials Science, Nanjing, 210046, China
| | - Weiben Yang
- Nanjing Normal University Center for Analysis and Testing, College of Life Sciences, School of Chemistry and Materials Science, Nanjing, 210046, China
| | - Hongjie Sheng
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Nanjing, 210008, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Fang Wang
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Nanjing, 210008, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Jean Damascene Harindintwali
- CAS Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Nanjing, 210008, China; University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - H M S K Herath
- Department of Export Agriculture, Faculty of Animal Science and Export Agriculture, Uva Wellassa University, Passara Road, Badulla, 90 000, Sri Lanka
| | - Yinping Zhang
- Nanjing Normal University Center for Analysis and Testing, College of Life Sciences, School of Chemistry and Materials Science, Nanjing, 210046, China.
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Gu M, Fang W, Li X, Yang W, Waigi MG, Kengara FO, Wu S, Han C, Zhang Y. Up-regulation of ribosomal and carbon metabolism proteins enhanced pyrene biodegradation in fulvic acid-induced biofilm system. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 294:118602. [PMID: 34856247 DOI: 10.1016/j.envpol.2021.118602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 06/13/2023]
Abstract
The polycyclic aromatic hydrocarbons (PAHs) that enter the aqueous phase usually coexist with fulvic acid (FA). Therefore, we initiated this investigation to explore the influences of FA on bacterial biofilm formation and its potential to biodegrade pyrene (PYR), using electron microscopic techniques and isobaric tags for relative and absolute quantification (iTRAQ). Our results revealed that FA stimulated biofilm formation and enhanced the biodegradation of PYR. First, FA favored the three-dimensional proliferation of bacteria, with an OD590/OD600 value of up to 14.78, and the extracellular surfaces covered by a layer of biomaterials. Distinctive intracellular morphologies of texture and organization were accompanied by reduced inter-bacterial distances of less than 0.31 μm. The biofilms formed displayed interactions between FA and surficial proteins, as noted by band shifts for the C-O and CO groups. Strikingly, FA triggered the upregulation of 130 proteins that were either operational in biofilm formation or in metabolic adjustments; with the changes supported by the increasing intensity of free amino acids and the newly generated N-O bonds. The results above revealed that the enhanced biodegradation was related to the up-regulation of the proteins functioned for ribosomal and carbon metabolism, and the ultra-structural changes in FA-induced biofilm system.
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Affiliation(s)
- Minfen Gu
- Center for Analysis and Testing, School of Chemistry and Materials, Nanjing Normal University, Nanjing, 210023, China
| | - WenWen Fang
- Center for Analysis and Testing, School of Chemistry and Materials, Nanjing Normal University, Nanjing, 210023, China
| | - Xiaoning Li
- Center for Analysis and Testing, School of Chemistry and Materials, Nanjing Normal University, Nanjing, 210023, China
| | - Weiben Yang
- Center for Analysis and Testing, School of Chemistry and Materials, Nanjing Normal University, Nanjing, 210023, China
| | - Michael Gatheru Waigi
- Institute of Organic Contaminant Control and Soil Remediation, College of Resources and Environmental Sciences, Nanjing Agricultural University, China
| | - Fredrick Orori Kengara
- School of Pure and Applied Sciences, Bomet University College, P.O. Box 701, 20400, Bomett, Kenya
| | - Shixi Wu
- Center for Analysis and Testing, School of Chemistry and Materials, Nanjing Normal University, Nanjing, 210023, China
| | - Cheng Han
- Center for Analysis and Testing, School of Chemistry and Materials, Nanjing Normal University, Nanjing, 210023, China
| | - Yinping Zhang
- Center for Analysis and Testing, School of Chemistry and Materials, Nanjing Normal University, Nanjing, 210023, China.
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9
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Extracellular haem utilization by the opportunistic pathogen Pseudomonas aeruginosa and its role in virulence and pathogenesis. Adv Microb Physiol 2021; 79:89-132. [PMID: 34836613 DOI: 10.1016/bs.ampbs.2021.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Iron is an essential micronutrient for all bacteria but presents a significant challenge given its limited bioavailability. Furthermore, iron's toxicity combined with the need to maintain iron levels within a narrow physiological range requires integrated systems to sense, regulate and transport a variety of iron complexes. Most bacteria encode systems to chelate and transport ferric iron (Fe3+) via siderophore receptor mediated uptake or via cytoplasmic energy dependent transport systems. Pathogenic bacteria have further lowered the barrier to iron acquisition by employing systems to utilize haem as a source of iron. Haem, a lipophilic and toxic molecule, presents a significant challenge for transport into the cell. As such pathogenic bacteria have evolved sophisticated cell surface signaling (CSS) and transport systems to sense and obtain haem from the host. Once internalized haem is cleaved by both oxidative and non-oxidative mechanisms to release iron. Herein we summarize our current understanding of the mechanism of haem sensing, uptake and utilization in Pseudomonas aeruginosa, its role in pathogenesis and virulence, and the potential of these systems as antimicrobial targets.
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10
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Krell T, Gavira JA, Velando F, Fernández M, Roca A, Monteagudo-Cascales E, Matilla MA. Histamine: A Bacterial Signal Molecule. Int J Mol Sci 2021; 22:6312. [PMID: 34204625 PMCID: PMC8231116 DOI: 10.3390/ijms22126312] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 02/07/2023] Open
Abstract
Bacteria have evolved sophisticated signaling mechanisms to coordinate interactions with organisms of other domains, such as plants, animals and human hosts. Several important signal molecules have been identified that are synthesized by members of different domains and that play important roles in inter-domain communication. In this article, we review recent data supporting that histamine is a signal molecule that may play an important role in inter-domain and inter-species communication. Histamine is a key signal molecule in humans, with multiple functions, such as being a neurotransmitter or modulator of immune responses. More recent studies have shown that bacteria have evolved different mechanisms to sense histamine or histamine metabolites. Histamine sensing in the human pathogen Pseudomonas aeruginosa was found to trigger chemoattraction to histamine and to regulate the expression of many virulence-related genes. Further studies have shown that many bacteria are able to synthesize and secrete histamine. The release of histamine by bacteria in the human gut was found to modulate the host immune responses and, at higher doses, to result in host pathologies. The elucidation of the role of histamine as an inter-domain signaling molecule is an emerging field of research and future investigation is required to assess its potential general nature.
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Affiliation(s)
- Tino Krell
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain; (F.V.); (E.M.-C.)
| | - José A. Gavira
- Laboratory of Crystallographic Studies, IACT (CSIC-UGR), Avenida de las Palmeras 4, 18100 Armilla, Spain;
| | - Félix Velando
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain; (F.V.); (E.M.-C.)
| | - Matilde Fernández
- Department of Microbiology, Facultad de Farmacia, Campus Universitario de Cartuja, Universidad de Granada, 18071 Granada, Spain; (M.F.); (A.R.)
| | - Amalia Roca
- Department of Microbiology, Facultad de Farmacia, Campus Universitario de Cartuja, Universidad de Granada, 18071 Granada, Spain; (M.F.); (A.R.)
| | - Elizabet Monteagudo-Cascales
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain; (F.V.); (E.M.-C.)
| | - Miguel A. Matilla
- Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Prof. Albareda 1, 18008 Granada, Spain; (F.V.); (E.M.-C.)
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11
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Reales-Calderón JA, Sun Z, Mascaraque V, Pérez-Navarro E, Vialás V, Deutsch EW, Moritz RL, Gil C, Martínez JL, Molero G. A wide-ranging Pseudomonas aeruginosa PeptideAtlas build: A useful proteomic resource for a versatile pathogen. J Proteomics 2021; 239:104192. [PMID: 33757883 PMCID: PMC8668395 DOI: 10.1016/j.jprot.2021.104192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/17/2021] [Accepted: 03/10/2021] [Indexed: 01/05/2023]
Abstract
Pseudomonas aeruginosa is an important opportunistic human pathogen with high prevalence in nosocomial infections. This microorganism is a good model for understanding biological processes such as the quorum-sensing response, the metabolic integration of virulence, the mechanisms of global regulation of bacterial physiology, and the evolution of antibiotic resistance. Till now, P. aeruginosa proteomic data, although available in several on-line repositories, were dispersed and difficult to access. In the present work, proteomes of the PAO1 strain grown under different conditions and from diverse cellular compartments have been joined to build the Pseudomonas PeptideAtlas. This resource is a comprehensive mass spectrometry-derived peptide and inferred protein database with 71.3% coverage of the total predicted proteome of P. aeruginosa PAO1, the highest coverage among bacterial PeptideAtlas datasets. The proteins included cover 89% of metabolic proteins, 72% of proteins involved in genetic information processing, 83% of proteins responsible for environmental information processing, more than 88% of the ones related to quorum sensing and biofilm formation, and 89% of proteins responsible for antimicrobial resistance. It exemplifies a necessary tool for targeted proteomics studies, system-wide observations, and cross-species observational studies. The manuscript describes the building of the PeptideAtlas and the contribution of the different proteomic data used. SIGNIFICANCE: Pseudomonas aeruginosa is among the most versatile human bacterial pathogens. Studies of its proteome are very important as they can reveal virulence factors and mechanisms of antibiotic resistance. The construction of a proteomic resource such as the PeptideAtlas enables targeted proteomics studies, system-wide observations, and cross-species observational studies.
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Affiliation(s)
- J A Reales-Calderón
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
| | - Z Sun
- Institute for Systems Biology, Seattle, WA, USA
| | - V Mascaraque
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
| | - E Pérez-Navarro
- Unidad de Proteómica de la Universidad Complutense de Madrid, Spain
| | - V Vialás
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain
| | - E W Deutsch
- Institute for Systems Biology, Seattle, WA, USA
| | - R L Moritz
- Institute for Systems Biology, Seattle, WA, USA
| | - C Gil
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain; Unidad de Proteómica de la Universidad Complutense de Madrid, Spain
| | - J L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - G Molero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain.
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12
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Yokoyama T, Niinae T, Tsumagari K, Imami K, Ishihama Y, Hizukuri Y, Akiyama Y. The Escherichia coli S2P intramembrane protease RseP regulates ferric citrate uptake by cleaving the sigma factor regulator FecR. J Biol Chem 2021; 296:100673. [PMID: 33865858 PMCID: PMC8144685 DOI: 10.1016/j.jbc.2021.100673] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/08/2021] [Accepted: 04/14/2021] [Indexed: 02/03/2023] Open
Abstract
Escherichia coli RseP, a member of the site-2 protease family of intramembrane proteases, is involved in the activation of the σE extracytoplasmic stress response and elimination of signal peptides from the cytoplasmic membrane. However, whether RseP has additional cellular functions is unclear. In this study, we used mass spectrometry-based quantitative proteomic analysis to search for new substrates that might reveal unknown physiological roles for RseP. Our data showed that the levels of several Fec system proteins encoded by the fecABCDE operon (fec operon) were significantly decreased in an RseP-deficient strain. The Fec system is responsible for the uptake of ferric citrate, and the transcription of the fec operon is controlled by FecI, an alternative sigma factor, and its regulator FecR, a single-pass transmembrane protein. Assays with a fec operon expression reporter demonstrated that the proteolytic activity of RseP is essential for the ferric citrate-dependent upregulation of the fec operon. Analysis using the FecR protein and FecR-derived model proteins showed that FecR undergoes sequential processing at the membrane and that RseP participates in the last step of this sequential processing to generate the N-terminal cytoplasmic fragment of FecR that participates in the transcription of the fec operon with FecI. A shortened FecR construct was not dependent on RseP for activation, confirming this cleavage step is the essential and sufficient role of RseP. Our study unveiled that E. coli RseP performs the intramembrane proteolysis of FecR, a novel physiological role that is essential for regulating iron uptake by the ferric citrate transport system.
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Affiliation(s)
- Tatsuhiko Yokoyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Tomoya Niinae
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kazuya Tsumagari
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Koshi Imami
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yasushi Ishihama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Yohei Hizukuri
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.
| | - Yoshinori Akiyama
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.
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13
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Veyrier FJ, Nieves C, Lefrancois LH, Trigui H, Vincent AT, Behr MA. RskA Is a Dual Function Activator-Inhibitor That Controls SigK Activity Across Distinct Bacterial Genera. Front Microbiol 2020; 11:558166. [PMID: 33013790 PMCID: PMC7509140 DOI: 10.3389/fmicb.2020.558166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 08/14/2020] [Indexed: 01/25/2023] Open
Abstract
It has been previously shown that RskA, the anti-Sigma factor K of Mycobacterium tuberculosis, inhibits SigK and that mutations in RskA promote high expression of the SigK regulon. The latter observation led us to hypothesize that RskA mutations lead to loss of the anti-Sigma factor function. In this report, we used natural and artificial mutations in RskA to determine the basis of the SigK-RskA partnership. Consistent with predictions, the N-terminal cytoplasmic portion of RskA was sufficient on its own to inhibit SigK. Unexpectedly, RskA also served as an activator of SigK. This activation depended on the same N-terminal region and was enhanced by the membrane-extracellular portion of RskA. Based on this, we engineered similar truncations in a Gram-negative bacterium, namely Yersinia enterocolitica. Again, we observed that, with specific alterations of RskA, we were able to enhance SigK activity. Together these results support an alternative mechanism of anti-Sigma factor function, that we could term modulator (activator-inhibitor) in both Actinobacteria and Gram-negative bacteria, suggesting that Sigma factor activation by anti-Sigma factors could be under-recognized.
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Affiliation(s)
- Frédéric J Veyrier
- Bacterial Symbionts Evolution, Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, Université du Québec, Laval, QC, Canada
- McGill International TB Centre, Montreal, QC, Canada
| | - Cecilia Nieves
- Bacterial Symbionts Evolution, Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, Université du Québec, Laval, QC, Canada
- McGill International TB Centre, Montreal, QC, Canada
| | - Louise H Lefrancois
- McGill International TB Centre, Montreal, QC, Canada
- Department of Medicine, McGill University, Montreal, QC, Canada
| | - Hana Trigui
- Bacterial Symbionts Evolution, Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, Université du Québec, Laval, QC, Canada
- McGill International TB Centre, Montreal, QC, Canada
| | - Antony T Vincent
- Bacterial Symbionts Evolution, Centre Armand-Frappier Santé Biotechnologie, Institut National de la Recherche Scientifique, Université du Québec, Laval, QC, Canada
- McGill International TB Centre, Montreal, QC, Canada
| | - Marcel A Behr
- McGill International TB Centre, Montreal, QC, Canada
- Department of Medicine, McGill University, Montreal, QC, Canada
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14
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Jensen JL, Jernberg BD, Sinha SC, Colbert CL. Structural basis of cell-surface signaling by a conserved sigma regulator in Gram-negative bacteria. J Biol Chem 2020; 295:5795-5806. [PMID: 32107313 PMCID: PMC7186176 DOI: 10.1074/jbc.ra119.010697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 02/23/2020] [Indexed: 01/07/2023] Open
Abstract
Cell-surface signaling (CSS) in Gram-negative bacteria involves highly conserved regulatory pathways that optimize gene expression by transducing extracellular environmental signals to the cytoplasm via inner-membrane sigma regulators. The molecular details of ferric siderophore-mediated activation of the iron import machinery through a sigma regulator are unclear. Here, we present the 1.56 Å resolution structure of the periplasmic complex of the C-terminal CSS domain (CCSSD) of PupR, the sigma regulator in the Pseudomonas capeferrum pseudobactin BN7/8 transport system, and the N-terminal signaling domain (NTSD) of PupB, an outer-membrane TonB-dependent transducer. The structure revealed that the CCSSD consists of two subdomains: a juxta-membrane subdomain, which has a novel all-β-fold, followed by a secretin/TonB, short N-terminal subdomain at the C terminus of the CCSSD, a previously unobserved topological arrangement of this domain. Using affinity pulldown assays, isothermal titration calorimetry, and thermal denaturation CD spectroscopy, we show that both subdomains are required for binding the NTSD with micromolar affinity and that NTSD binding improves CCSSD stability. Our findings prompt us to present a revised model of CSS wherein the CCSSD:NTSD complex forms prior to ferric-siderophore binding. Upon siderophore binding, conformational changes in the CCSSD enable regulated intramembrane proteolysis of the sigma regulator, ultimately resulting in transcriptional regulation.
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Affiliation(s)
- Jaime L Jensen
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108
| | - Beau D Jernberg
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108
| | - Sangita C Sinha
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108
| | - Christopher L Colbert
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, North Dakota 58108.
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15
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Otero-Asman JR, García-García AI, Civantos C, Quesada JM, Llamas MA. Pseudomonas aeruginosa possesses three distinct systems for sensing and using the host molecule haem. Environ Microbiol 2019; 21:4629-4647. [PMID: 31390127 DOI: 10.1111/1462-2920.14773] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 08/05/2019] [Indexed: 12/18/2022]
Abstract
Pathogens have developed several strategies to obtain iron during infection, including the use of iron-containing molecules from the host. Haem accounts for the vast majority of the iron pool in vertebrates and thus represents an important source of iron for pathogens. Using a proteomic approach, we have identified in this work a previously uncharacterized system, which we name Hxu, that together with the known Has and Phu systems, is used by the human pathogen Pseudomonas aeruginosa to respond to haem. We show that the Has and Hxu systems are functional signal transduction pathways of the cell-surface signalling class and report the mechanism triggering the activation of these signalling systems. Both signalling cascades involve an outer membrane receptor (HasR and HxuA respectively) that upon sensing haem in the extracellular medium produces the activation of an σECF factor in the cytosol. HxuA has a major role in signalling and a minor role in haem acquisition in conditions in which the HasR and PhuR receptors or other sources of iron are present. Remarkably, P. aeruginosa compensates the lack of the HasR receptor by increasing the production of HxuA, which underscores the importance of haem signalling for this pathogen.
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Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - Ana I García-García
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - Cristina Civantos
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - José M Quesada
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008, Granada, Spain
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16
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Otero-Asman JR, Wettstadt S, Bernal P, Llamas MA. Diversity of extracytoplasmic function sigma (σ ECF ) factor-dependent signaling in Pseudomonas. Mol Microbiol 2019; 112:356-373. [PMID: 31206859 DOI: 10.1111/mmi.14331] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/10/2019] [Indexed: 12/23/2022]
Abstract
Pseudomonas bacteria are widespread and are found in soil and water, as well as pathogens of both plants and animals. The ability of Pseudomonas to colonize many different environments is facilitated by the multiple signaling systems these bacteria contain that allow Pseudomonas to adapt to changing circumstances by generating specific responses. Among others, signaling through extracytoplasmic function σ (σECF ) factors is extensively present in Pseudomonas. σECF factors trigger expression of functions required under particular conditions in response to specific signals. This manuscript reviews the phylogeny and biological roles of σECF factors in Pseudomonas, and highlights the diversity of σECF -signaling pathways of this genus in terms of function and activation. We show that Pseudomonas σECF factors belong to 16 different phylogenetic groups. Most of them are included within the iron starvation group and are mainly involved in iron acquisition. The second most abundant group is formed by RpoE-like σECF factors, which regulate the responses to cell envelope stress. Other groups controlling solvent tolerance, biofilm formation and the response to oxidative stress, among other functions, are present in lower frequency. The role of σECF factors in the virulence of Pseudomonas pathogenic species is described.
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Affiliation(s)
- Joaquín R Otero-Asman
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Sarah Wettstadt
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Patricia Bernal
- Department of Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
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17
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Sánchez-Hevia DL, Yuste L, Moreno R, Rojo F. Influence of the Hfq and Crc global regulators on the control of iron homeostasis inPseudomonas putida. Environ Microbiol 2018; 20:3484-3503. [DOI: 10.1111/1462-2920.14263] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Dione L. Sánchez-Hevia
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco; Madrid, 28049 Spain
| | - Luis Yuste
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco; Madrid, 28049 Spain
| | - Renata Moreno
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco; Madrid, 28049 Spain
| | - Fernando Rojo
- Departamento de Biotecnología Microbiana; Centro Nacional de Biotecnología, CSIC, Darwin 3, Cantoblanco; Madrid, 28049 Spain
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18
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Bastiaansen KC, Civantos C, Bitter W, Llamas MA. New Insights into the Regulation of Cell-Surface Signaling Activity Acquired from a Mutagenesis Screen of the Pseudomonas putida IutY Sigma/Anti-Sigma Factor. Front Microbiol 2017; 8:747. [PMID: 28512454 PMCID: PMC5411451 DOI: 10.3389/fmicb.2017.00747] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 04/11/2017] [Indexed: 01/18/2023] Open
Abstract
Cell-surface signaling (CSS) is a signal transfer system that allows Gram-negative bacteria to detect environmental signals and generate a cytosolic response. These systems are composed of an outer membrane receptor that senses the inducing signal, an extracytoplasmic function sigma factor (σECF) that targets the cytosolic response by modifying gene expression and a cytoplasmic membrane anti-sigma factor that keeps the σECF in an inactive state in the absence of the signal and transduces its presence from the outer membrane to the cytosol. Although CSS systems regulate bacterial processes as crucial as stress response, iron scavenging and virulence, the exact mechanisms that drive CSS are still not completely understood. Binding of the signal to the CSS receptor is known to trigger a signaling cascade that results in the regulated proteolysis of the anti-sigma factor and the activation of the σECF in the cytosol. This study was carried out to generate new insights in the proteolytic activation of CSS σECF. We performed a random mutagenesis screen of the unique IutY protein of Pseudomonas putida, a protein that combines a cytosolic σECF domain and a periplasmic anti-sigma factor domain in a single polypeptide. In response to the presence of an iron carrier, the siderophore aerobactin, in the extracellular medium, IutY is processed by two different proteases, Prc and RseP, which results in the release and activation of the σIutY domain. Our experiments show that all IutY mutant proteins that contain periplasmic residues depend on RseP for activation. In contrast, Prc is only required for mutant variants with a periplasmic domain longer than 50 amino acids, which indicates that the periplasmic region of IutY is trimmed down to ~50 amino acids creating the RseP substrate. Moreover, we have identified several conserved residues in the CSS anti-sigma factor family of which mutation leads to constitutive activation of their cognate σECF. These findings advance our knowledge on how CSS activity is regulated by the consecutive action of two proteases. Elucidation of the exact mechanism behind CSS activation will enable the development of strategies to block CSS in pathogenic bacteria.
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Affiliation(s)
- Karlijn C Bastiaansen
- Department of Environmental Protection, Estación Experimental del Zaidín (CSIC)Granada, Spain.,Section of Molecular Microbiology, Department of Molecular Cell Biology, VU University AmsterdamAmsterdam, Netherlands
| | - Cristina Civantos
- Department of Environmental Protection, Estación Experimental del Zaidín (CSIC)Granada, Spain
| | - Wilbert Bitter
- Section of Molecular Microbiology, Department of Molecular Cell Biology, VU University AmsterdamAmsterdam, Netherlands
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín (CSIC)Granada, Spain
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19
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Abstract
Iron is essential for the survival of most bacteria but presents a significant challenge given its limited bioavailability. Furthermore, the toxicity of iron combined with the need to maintain physiological iron levels within a narrow concentration range requires sophisticated systems to sense, regulate, and transport iron. Most bacteria have evolved mechanisms to chelate and transport ferric iron (Fe3+) via siderophore receptor systems, and pathogenic bacteria have further lowered this barrier by employing mechanisms to utilize the host's hemoproteins. Once internalized, heme is cleaved by both oxidative and nonoxidative mechanisms to release iron. Heme, itself a lipophilic and toxic molecule, presents a significant challenge for transport into the cell. As such, pathogenic bacteria have evolved sophisticated cell surface signaling and transport systems to obtain heme from the host. In this review, we summarize the structure and function of the heme-sensing and transport systems of pathogenic bacteria and the potential of these systems as antimicrobial targets.
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Affiliation(s)
- Weiliang Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201;
| | - Angela Wilks
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Maryland 21201;
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20
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Jensen JL, Balbo A, Neau DB, Chakravarthy S, Zhao H, Sinha SC, Colbert CL. Mechanistic Implications of the Unique Structural Features and Dimerization of the Cytoplasmic Domain of the Pseudomonas Sigma Regulator, PupR. Biochemistry 2015; 54:5867-77. [PMID: 26313375 PMCID: PMC4701049 DOI: 10.1021/acs.biochem.5b00826] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Gram-negative bacteria tightly regulate intracellular levels of iron, an essential nutrient. To ensure this strict control, some outer membrane TonB-dependent transporters (TBDTs) that are responsible for iron import stimulate their own transcription in response to extracellular binding by an iron-laden siderophore. This process is mediated by an inner membrane sigma regulator protein (an anti-sigma factor) that transduces an unknown periplasmic signal from the TBDT to release an intracellular sigma factor from the inner membrane, which ultimately upregulates TBDT transcription. Here, we use the Pseudomonas putida ferric-pseudobactin BN7/BN8 sigma regulator, PupR, as a model system to understand the molecular mechanism of this conserved class of sigma regulators. We have determined the X-ray crystal structure of the cytoplasmic anti-sigma domain (ASD) of PupR to 2.0 Å. Size exclusion chromatography, small-angle X-ray scattering, and sedimentation velocity analytical ultracentrifugation all indicate that, in contrast to other ASDs, the PupR-ASD exists as a dimer in solution. Mutagenesis of residues at the dimer interface identified from the crystal structure disrupts dimerization and protein stability, as determined by sedimentation velocity analytical ultracentrifugation and thermal denaturation circular dichroism spectroscopy. These combined results suggest that this type of inner membrane sigma regulator may utilize an unusual mechanism to sequester their cognate sigma factors and prevent transcription activation.
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Affiliation(s)
- Jaime L. Jensen
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Andrea Balbo
- Biomedical Engineering and Physical Science Shared Resource, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - David B. Neau
- Department of Chemistry and Chemical Biology, Cornell University, Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Srinivas Chakravarthy
- Bio-CAT, Advanced Photon Source, 9700 South Cass Avenue, 3Bldg. 435B, Argonne, IL 60439, USA
| | - Huaying Zhao
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Sangita C. Sinha
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
| | - Christopher L. Colbert
- Department of Chemistry and Biochemistry, North Dakota State University, Fargo, ND 58108-6050, USA
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