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Yang F, Yang F, Huang J, Yu H, Qiao S. Microcin C7 as a Potential Antibacterial-Immunomodulatory Agent in the Postantibiotic Era: Overview of Its Bioactivity Aspects and Applications. Int J Mol Sci 2024; 25:7213. [PMID: 39000321 PMCID: PMC11241378 DOI: 10.3390/ijms25137213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/16/2024] Open
Abstract
In the postantibiotic era, the pathogenicity and resistance of pathogens have increased, leading to an increase in intestinal inflammatory disease. Bacterial infections remain the leading cause of animal mortality. With increasing resistance to antibiotics, there has been a significant decrease in resistance to both inflammation and disease in animals, thus decreasing production efficiency and increasing production costs. These side effects have serious consequences and have detracted from the development of China's pig industry. Microcin C7 (McC7) demonstrates potent antibacterial activity against a broad spectrum of pathogens, stable physicochemical properties, and low toxicity, reducing the likelihood of resistance development. Thus, McC7 has received increasing attention as a potential clinical antibacterial and immunomodulatory agent. McC7 has the potential to serve as a new generation of antibiotic substitutes; however, its commercial applications in the livestock and poultry industry have been limited. In this review, we summarize and discuss the biosynthesis, biochemical properties, structural characteristics, mechanism of action, and immune strategies of McC7. We also describe the ability of McC7 to improve intestinal health. Our aim in this study was to provide a theoretical basis for the application of McC7 as a new feed additive or new veterinary drug in the livestock and poultry breeding industry, thus providing a new strategy for alleviating resistance through feed and mitigating drug resistance. Furthermore, this review provides insight into the new functions and anti-infection mechanisms of bacteriocin peptides and proposes crucial ideas for the research, product development, and application of bacteriocin peptides in different fields, such as the food and medical industries.
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Affiliation(s)
- Fengjuan Yang
- State Key Laboratory of Animal Nutrition and Feeding, Ministry of Agriculture and Rural Affairs Feed Industry Centre, China Agricultural University, Beijing 100193, China
- Beijing Biofeed Additives Key Laboratory, Beijing 100193, China
| | - Feiyun Yang
- Chongqing Academy of Animal Science, Rongchang, Chongqing 402460, China
- National Center of Technology Innovation for Pigs, Rongchang, Chongqing 402460, China
| | - Jinxiu Huang
- Chongqing Academy of Animal Science, Rongchang, Chongqing 402460, China
- National Center of Technology Innovation for Pigs, Rongchang, Chongqing 402460, China
| | - Haitao Yu
- State Key Laboratory of Animal Nutrition and Feeding, Ministry of Agriculture and Rural Affairs Feed Industry Centre, China Agricultural University, Beijing 100193, China
- Beijing Biofeed Additives Key Laboratory, Beijing 100193, China
| | - Shiyan Qiao
- State Key Laboratory of Animal Nutrition and Feeding, Ministry of Agriculture and Rural Affairs Feed Industry Centre, China Agricultural University, Beijing 100193, China
- Beijing Biofeed Additives Key Laboratory, Beijing 100193, China
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2
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Goult JD, Van DCL, Taylor YV, Inns PG, Kaminska R, Vesely M, Kleanthous C, Paci E. Structural constraints of pyocin S2 import through the ferripyoverdine receptor FpvAI. PNAS NEXUS 2024; 3:pgae124. [PMID: 38577260 PMCID: PMC10994204 DOI: 10.1093/pnasnexus/pgae124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 03/12/2024] [Indexed: 04/06/2024]
Abstract
TonB-dependent transporters (TBDTs) mediate energized transport of essential nutrients into gram-negative bacteria. TBDTs are increasingly being exploited for the delivery of antibiotics to drug-resistant bacteria. While much is known about ground state complexes of TBDTs, few details have emerged about the transport process itself. In this study, we exploit bacteriocin parasitization of a TBDT to probe the mechanics of transport. Previous work has shown that the N-terminal domain of Pseudomonas aeruginosa-specific bacteriocin pyocin S2 (PyoS2NTD) is imported through the pyoverdine receptor FpvAI. PyoS2NTD transport follows the opening of a proton-motive force-dependent pore through FpvAI and the delivery of its own TonB box that engages TonB. We use molecular models and simulations to formulate a complete translocation pathway for PyoS2NTD that we validate using protein engineering and cytotoxicity measurements. We show that following partial removal of the FpvAI plug domain which occludes the channel, the pyocin's N-terminus enters the channel by electrostatic steering and ratchets to the periplasm. Application of force, mimicking that exerted by TonB, leads to unraveling of PyoS2NTD as it squeezes through the channel. Remarkably, while some parts of PyoS2NTD must unfold, complete unfolding is not required for transport, a result we confirmed by disulfide bond engineering. Moreover, the section of the FpvAI plug that remains embedded in the channel appears to serve as a buttress against which PyoS2NTD is pushed to destabilize the domain. Our study reveals the limits of structural deformation that accompanies import through a TBDT and the role the TBDT itself plays in accommodating transport.
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Affiliation(s)
- Jonathan D Goult
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Daniel C L Van
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Yasmin V Taylor
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Patrick G Inns
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Renata Kaminska
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Martin Vesely
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Emanuele Paci
- Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna 40127, Italy
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3
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Zhao X, Wang W, Zeng X, Xu R, Yuan B, Yu W, Wang M, Jia R, Chen S, Zhu D, Liu M, Yang Q, Wu Y, Zhang S, Huang J, Ou X, Sun D, Cheng A. Klebicin E, a pore-forming bacteriocin of Klebsiella pneumoniae, exploits the porin OmpC and the Ton system for translocation. J Biol Chem 2024; 300:105694. [PMID: 38301890 PMCID: PMC10906532 DOI: 10.1016/j.jbc.2024.105694] [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: 09/21/2023] [Revised: 01/09/2024] [Accepted: 01/15/2024] [Indexed: 02/03/2024] Open
Abstract
Bacteriocins, which have narrow-spectrum activity and limited adverse effects, are promising alternatives to antibiotics. In this study, we identified klebicin E (KlebE), a small bacteriocin derived from Klebsiella pneumoniae. KlebE exhibited strong efficacy against multidrug-resistant K. pneumoniae isolates and conferred a significant growth advantage to the producing strain during intraspecies competition. A giant unilamellar vesicle leakage assay demonstrated the unique membrane permeabilization effect of KlebE, suggesting that it is a pore-forming toxin. In addition to a C-terminal toxic domain, KlebE also has a disordered N-terminal domain and a globular central domain. Pulldown assays and soft agar overlay experiments revealed the essential role of the outer membrane porin OmpC and the Ton system in KlebE recognition and cytotoxicity. Strong binding between KlebE and both OmpC and TonB was observed. The TonB-box, a crucial component of the toxin-TonB interaction, was identified as the 7-amino acid sequence (E3ETLTVV9) located in the N-terminal region. Further studies showed that a region near the bottom of the central domain of KlebE plays a primary role in recognizing OmpC, with eight residues surrounding this region identified as essential for KlebE toxicity. Finally, based on the discrepancies in OmpC sequences between the KlebE-resistant and sensitive strains, it was found that the 91st residue of OmpC, an aspartic acid residue, is a key determinant of KlebE toxicity. The identification and characterization of this toxin will facilitate the development of bacteriocin-based therapies targeting multidrug-resistant K. pneumoniae infections.
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Affiliation(s)
- Xinxin Zhao
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Wenyu Wang
- Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Xiaoli Zeng
- Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Rong Xu
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China
| | - Bing Yuan
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China
| | - Wenyao Yu
- Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Mingshu Wang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Renyong Jia
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Shun Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Dekang Zhu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Mafeng Liu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Qiao Yang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Ying Wu
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Shaqiu Zhang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
| | - Juan Huang
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Xumin Ou
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Di Sun
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China
| | - Anchun Cheng
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, China; Institute of Veterinary Medicine and Immunology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China; Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People's Republic of China, Chengdu, Sichuan, China.
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4
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Artuso I, Poddar H, Evans BA, Visca P. Genomics of Acinetobacter baumannii iron uptake. Microb Genom 2023; 9:mgen001080. [PMID: 37549061 PMCID: PMC10483418 DOI: 10.1099/mgen.0.001080] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/10/2023] [Indexed: 08/09/2023] Open
Abstract
Iron is essential for growth in most bacteria due to its redox activity and its role in essential metabolic reactions; it is a cofactor for many bacterial enzymes. The bacterium Acinetobacter baumannii is a multidrug-resistant nosocomial pathogen. A. baumannii responds to low iron availability imposed by the host through the exploitation of multiple iron-acquisition strategies, which are likely to deliver iron to the cell under a variety of environmental conditions, including human and animal infection. To date, six different gene clusters for active iron uptake have been described in A. baumannii , encoding protein systems involved in (i) ferrous iron uptake (feo ); (ii) haem uptake (hemT and hemO ); and (iii) synthesis and transport of the baumannoferrin(s) (bfn ), acinetobactin (bas /bau ) and fimsbactin(s) (fbs ) siderophores. Here we describe the structure, distribution and phylogeny of iron-uptake gene clusters among >1000 genotypically diverse A. baumannii isolates, showing that feo , hemT , bfn and bas /bau clusters are very prevalent across the dataset, whereas the additional haem-uptake system hemO is only present in a portion of the dataset and the fbs gene cluster is very rare. Since the expression of multiple iron-uptake clusters can be linked to virulence, the presence of the additional haem-uptake system hemO may have contributed to the success of some A. baumannii clones.
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Affiliation(s)
- Irene Artuso
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Harsh Poddar
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
| | - Benjamin A. Evans
- Norwich Medical School, University of East Anglia, Rosalind Franklin Road, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Paolo Visca
- Department of Science, Roma Tre University, Viale G. Marconi 446, 00146 Rome, Italy
- Fondazione Santa Lucia IRCCS, Via Ardeatina, 306/354, 00179 Rome, Italy
- National Biodiversity Future Centre, Palermo 90133, Italy
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5
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Garland GD, Patil KR, Turner SD, Willis AE. The Pioneer platform: A novel approach for selection of selective anti-cancer cytotoxic activity in bacteria through co-culturing with engineered human cells. PLoS One 2023; 18:e0286741. [PMID: 37279202 DOI: 10.1371/journal.pone.0286741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 05/23/2023] [Indexed: 06/08/2023] Open
Abstract
Most of the small-molecule drugs approved for the treatment of cancer over the past 40 years are based on natural compounds. Bacteria provide an extensive reservoir for the development of further anti-cancer therapeutics to meet the challenges posed by the diversity of these malignant diseases. While identifying cytotoxic compounds is often easy, achieving selective targeting of cancer cells is challenging. Here we describe a novel experimental approach (the Pioneer platform) for the identification and development of 'pioneering' bacterial variants that either show or are conduced to exhibit selective contact-independent anti-cancer cytotoxic activities. We engineered human cancer cells to secrete Colicin M that repress the growth of the bacterium Escherichia coli, while immortalised non-transformed cells were engineered to express Chloramphenicol Acetyltransferase capable of relieving the bacteriostatic effect of Chloramphenicol. Through co-culturing of E. coli with these two engineered human cell lines, we show bacterial outgrowth of DH5α E. coli is constrained by the combination of negative and positive selection pressures. This result supports the potential for this approach to screen or adaptively evolve 'pioneering' bacterial variants that can selectively eliminate the cancer cell population. Overall, the Pioneer platform demonstrates potential utility for drug discovery through multi-partner experimental evolution.
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Affiliation(s)
- Gavin D Garland
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Kiran R Patil
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Suzanne D Turner
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- CEITEC, Masaryk University, Brno, Czech Republic
| | - Anne E Willis
- MRC Toxicology Unit, University of Cambridge, Cambridge, United Kingdom
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6
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Peukert C, Gasser V, Orth T, Fritsch S, Normant V, Cunrath O, Schalk IJ, Brönstrup M. Trojan Horse Siderophore Conjugates Induce Pseudomonas aeruginosa Suicide and Qualify the TonB Protein as a Novel Antibiotic Target. J Med Chem 2023; 66:553-576. [PMID: 36548006 PMCID: PMC9841981 DOI: 10.1021/acs.jmedchem.2c01489] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Indexed: 12/24/2022]
Abstract
Rising infection rates with multidrug-resistant pathogens calls for antibiotics with novel modes of action. Herein, we identify the inner membrane protein TonB, a motor of active uptake in Gram-negative bacteria, as a novel target in antimicrobial therapy. The interaction of the TonB box of outer membrane transporters with TonB is crucial for the internalization of essential metabolites. We designed TonB box peptides and coupled them with synthetic siderophores in order to facilitate their uptake into bacteria in up to 32 synthetic steps. Three conjugates repressed the growth of Pseudomonas aeruginosa cells unable to produce their own siderophores, with minimal inhibitory concentrations between 0.1 and 0.5 μM. The transporters mediating uptake of these compounds were identified as PfeA and PirA. The study illustrates a variant of cellular suicide where a transporter imports its own inhibitor and demonstrates that artificial siderophores can import cargo with molecular weights up to 4 kDa.
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Affiliation(s)
- Carsten Peukert
- Department
of Chemical Biology, Helmholtz Centre for
Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Véronique Gasser
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Till Orth
- Department
of Chemical Biology, Helmholtz Centre for
Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Sarah Fritsch
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Vincent Normant
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Olivier Cunrath
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Isabelle J. Schalk
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Mark Brönstrup
- Department
of Chemical Biology, Helmholtz Centre for
Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
- German
Center for Infection Research (DZIF), Site Hannover-Braunschweig, 38124 Braunschweig, Germany
- Center for
Biomolecular Drug Research (BMWZ), Schneiderberg 38, 30167 Hannover, Germany
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7
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Resistance Mechanism and Physiological Effects of Microcin Y in Salmonella enterica subsp. enterica Serovar Typhimurium. Microbiol Spectr 2022; 10:e0185922. [PMID: 36453909 PMCID: PMC9769762 DOI: 10.1128/spectrum.01859-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Salmonella bacteria pose a significant threat to animal husbandry and human health due to their virulence and multidrug resistance. The lasso peptide MccY is a recently discovered antimicrobial peptide that acts against various serotypes of Salmonella. In this study, we further explore the resistance mechanism and activity of MccY. Mutants of Ton system genes, including tonB, exbB, and exbD, in Salmonella enterica subsp. enterica serovar Typhimurium were constructed, and the MICs to MccY exhibited significant increases in these deletion mutants compared to the MIC of the parent strain. Subsequently, MccY resistance was quantitatively analyzed, and these mutants also showed greatly reduced rates of killing, even with a high concentration of MccY. In addition, a minimal medium with low iron environment enhanced the sensitivity of these mutants to MccY. Measurements of a series of physiological indicators, including iron utilization, biofilm formation, and motility, demonstrated that MccY may decrease the virulence of S. Typhimurium. Transcriptomic analysis showed that iron utilization, biofilm formation, flagellar assembly, and virulence-related genes were downregulated to varying degrees when S. Typhimurium was treated with MccY. In conclusion, deletion of Ton system genes resulted in resistance to MccY and the susceptibility of these mutants to MccY was increased and differed under a low-iron condition. This lasso peptide can alter multiple physiological properties of S. Typhimurium. Our study will contribute to improve the knowledge and understanding of the mechanism of MccY resistance in Salmonella strains. IMPORTANCE The resistance of Salmonella to traditional antibiotics remains a serious challenge. Novel anti-Salmonella drugs are urgently needed to address the looming crisis. The newly identified antimicrobial peptide MccY shows broad prospects for development and application because of its obvious antagonistic effect on various serotypes of Salmonella. However, our previous study showed that the peptide could confer resistance to Salmonella by disrupting the receptor gene fhuA. In this study, we further explored the potential resistance mechanism of MccY and demonstrated the importance of the Salmonella Ton complex for MccY transport. Disruption in Ton system genes resulted in S. Typhimurium resistance to this peptide, and MccY could alter multiple bacterial physiological properties. In summary, this study further explored the resistance mechanism and antibacterial effect of MccY in S. Typhimurium and provided a scientific basis for its development and application.
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8
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Marković KG, Grujović MŽ, Koraćević MG, Nikodijević DD, Milutinović MG, Semedo-Lemsaddek T, Djilas MD. Colicins and Microcins Produced by Enterobacteriaceae: Characterization, Mode of Action, and Putative Applications. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:11825. [PMID: 36142096 PMCID: PMC9517006 DOI: 10.3390/ijerph191811825] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 06/15/2023]
Abstract
Enterobacteriaceae are widely present in many environments related to humans, including the human body and the food that they consume, from both plant or animal origin. Hence, they are considered relevant members of the gastrointestinal tract microbiota. On the other hand, these bacteria are also recognized as putative pathogens, able to impair human health and, in food, they are considered indicators for the microbiological quality and hygiene status of a production process. Nevertheless, beneficial properties have also been associated with Enterobacteriaceae, such as the ability to synthesize peptides and proteins, which can have a role in the structure of microbial communities. Among these antimicrobial molecules, those with higher molecular mass are called colicins, while those with lower molecular mass are named microcins. In recent years, some studies show an emphasis on molecules that can help control the development of pathogens. However, not enough data are available on this subject, especially related to microcins. Hence, this review gathers and summarizes current knowledge on colicins and microcins, potential usage in the treatment of pathogen-associated diseases and cancer, as well as putative applications in food biotechnology.
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Affiliation(s)
- Katarina G. Marković
- Institute for Information Technologies, Department of Science, University of Kragujevac, Jovana Cvijića bb, 34000 Kragujevac, Serbia
| | - Mirjana Ž. Grujović
- Institute for Information Technologies, Department of Science, University of Kragujevac, Jovana Cvijića bb, 34000 Kragujevac, Serbia
| | - Maja G. Koraćević
- Innovation Center, University of Niš, 18000 Niš, Serbia
- Faculty of Medicine, Department of Pharmacy, University of Niš, 18000 Niš, Serbia
| | - Danijela D. Nikodijević
- Faculty of Science, Department of Biology and Ecology, University of Kragujevac, Radoja Domanovića 12, 34000 Kragujevac, Serbia
| | - Milena G. Milutinović
- Faculty of Science, Department of Biology and Ecology, University of Kragujevac, Radoja Domanovića 12, 34000 Kragujevac, Serbia
| | - Teresa Semedo-Lemsaddek
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisboa, Portugal
| | - Milan D. Djilas
- Institute for Public Health of Vojvodina, Futoška 121, 21000 Novi Sad, Serbia
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9
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Bacteriocin-Producing Escherichia coli Isolated from the Gastrointestinal Tract of Farm Animals: Prevalence, Molecular Characterization and Potential for Application. Microorganisms 2022; 10:microorganisms10081558. [PMID: 36013976 PMCID: PMC9413453 DOI: 10.3390/microorganisms10081558] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 07/21/2022] [Accepted: 07/29/2022] [Indexed: 11/18/2022] Open
Abstract
Due to the spread of antibiotic-resistant bacteria, new alternatives to antibiotics and ways to prevent infections are being sought. Bacteriocin-producing bacteria are therefore attracting attention due to their probiotic potential as a safe alternative to antimicrobial drugs. The aim of this work was to determine the prevalence of bacteriocin-encoded genes among Escherichia coli strains from healthy farm animals and to characterize the presence of virulence-associated genes, the possibility of prophage induction, and hemolytic and bacterial antagonistic activity of the bacteriocin-producing E. coli in order to reveal their potential for application. It was found that 17 of 72 E. coli strains (23.6%) produced bacteriocins. Among them, 18 out of 30 bacteriocin genes were detected: the most prevalent genes were those for microcin M (58.8%), colicin E1 (52.9%), and colicin M (35.3%). Colicin Ia (29.4%), colicin E9, colicin Ib, colicin B (23.5%), and colicin E9 (17.7%) genes were also frequent, while the prevalence of genes encoding microcins V, B17, and H47 and colicins E3, K, N, U, Y, 5, and 10 did not exceed 11.8%. At least two different bacteriocin genes were detected in all 17 bacteriocinogenic strains; the highest number of different bacteriocin genes detected in one strain was seven genes. E. coli strains with combinations of colicin E1 and E or microcin M and colicin E1 genes were more prevalent than others (17.7%). Among the 17 bacteriocin-producing E. coli strains, 5.9% were hemolytic, 47.1% contained prophages, and 58.8% carried genes encoding toxins. Cell-free supernatants of bacteriocin-producing strains were shown to inhibit the growth of pathogenic E. coli strains belonging to the APEC, STEC, and ETEC pathotypes. Thus, among the studied bacteriocin-producing E. coli isolated from the gastrointestinal tract of farm animals, three strains with high antagonistic bacterial activity and the absence of pathogenicity genes, prophages, and hemolytic activity were identified and therefore have potential for application.
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10
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Calcuttawala F, Pal A, Nath P, Kar R, Hazra D, Pal R. Structural and functional insights into colicin: a new paradigm in drug discovery. Arch Microbiol 2021; 204:37. [PMID: 34928429 DOI: 10.1007/s00203-021-02689-6] [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: 06/10/2021] [Revised: 11/03/2021] [Accepted: 11/03/2021] [Indexed: 11/28/2022]
Abstract
Colicins are agents of allelopathic interactions produced by certain enterobacteria which give them a competitive advantage in the environment. These protein molecules are mostly encoded by plasmids. The colicin operon consists of the activity, immunity and the lysis genes. The activity protein is responsible for the killing activity, the immunity protein protects the producer cell from the lethal action of colicin and the lysis protein facilitates its release. Colicins are primarily composed of three domains, namely the receptor-binding domain, the translocation domain and the cytotoxic domain. The protein molecule binds to its cognate receptor on the target cell via the receptor-binding domain and undergoes translocation into the cell either via the Tol system or the Ton system. After gaining entry into the target cell, there are various mechanisms by which colicins exert their lethality. These comprise DNase activity, RNase activity and pore formation in the target cell membrane or peptidoglycan synthesis inhibition. This review gives a detailed insight into the structural and functional aspect of colicins and their mode of action. This knowledge is of immense significance because colicins are being considered as very useful alternatives to conventional antibiotics in the treatment of multidrug-resistant infections. Besides, they also have a negligible harmful impact on the commensals. Thus, before tapping their therapeutic potential, it is imperative to know their structure and mechanism of action in detail.
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Affiliation(s)
- Fatema Calcuttawala
- Department of Microbiology, Sister Nivedita University, Kolkata, 700156, India.
| | - Ankita Pal
- Department of Microbiology, Sister Nivedita University, Kolkata, 700156, India
| | - Papri Nath
- Department of Microbiology, Sister Nivedita University, Kolkata, 700156, India
| | - Riya Kar
- Department of Microbiology, Sister Nivedita University, Kolkata, 700156, India
| | - Debraj Hazra
- Department of Microbiology, Sister Nivedita University, Kolkata, 700156, India
| | - Rajat Pal
- Department of Microbiology, Sister Nivedita University, Kolkata, 700156, India
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11
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Mcc1229, an Stx2a-amplifying microcin, is produced in vivo and requires CirA for activity. Infect Immun 2021; 90:e0058721. [PMID: 34871041 PMCID: PMC8853679 DOI: 10.1128/iai.00587-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) strains, including the foodborne pathogen E. coli O157:H7, are responsible for thousands of hospitalizations each year. Various environmental triggers can modulate pathogenicity in EHEC by inducing the expression of Shiga toxin (Stx), which is encoded on a lambdoid prophage and transcribed together with phage late genes. Cell-free supernatants of the sequence type 73 (ST73) E. coli strain 0.1229 are potent inducers of Stx2a production in EHEC, suggesting that 0.1229 secretes a factor that activates the SOS response and leads to phage lysis. We previously demonstrated that this factor, designated microcin 1229 (Mcc1229), was proteinaceous and plasmid-encoded. To further characterize Mcc1229 and support its classification as a microcin, we investigated its regulation, determined its receptor, and identified loci providing immunity. The production of Mcc1229 was increased upon iron limitation, as determined by an enzyme-linked immunosorbent assay (ELISA), lacZ fusions, and quantitative real-time PCR (qRT-PCR). Spontaneous Mcc1229-resistant mutants and targeted gene deletion revealed that CirA was the Mcc1229 receptor. TonB, which interacts with CirA in the periplasm, was also essential for Mcc1229 import. Subcloning of the Mcc1229 plasmid indicated that Mcc activity was neutralized by two open reading frames (ORFs), each predicted to encode a domain of unknown function (DUF)-containing protein. In a germfree mouse model of infection, colonization with 0.1229 suppressed subsequent colonization by EHEC. Although Mcc1229 was produced in vivo, it was dispensable for colonization suppression. The regulation, import, and immunity determinants identified here are consistent with features of other Mccs, suggesting that Mcc1229 should be included in this class of small molecules.
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12
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Bin Hafeez A, Jiang X, Bergen PJ, Zhu Y. Antimicrobial Peptides: An Update on Classifications and Databases. Int J Mol Sci 2021; 22:11691. [PMID: 34769122 PMCID: PMC8583803 DOI: 10.3390/ijms222111691] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/25/2021] [Indexed: 02/06/2023] Open
Abstract
Antimicrobial peptides (AMPs) are distributed across all kingdoms of life and are an indispensable component of host defenses. They consist of predominantly short cationic peptides with a wide variety of structures and targets. Given the ever-emerging resistance of various pathogens to existing antimicrobial therapies, AMPs have recently attracted extensive interest as potential therapeutic agents. As the discovery of new AMPs has increased, many databases specializing in AMPs have been developed to collect both fundamental and pharmacological information. In this review, we summarize the sources, structures, modes of action, and classifications of AMPs. Additionally, we examine current AMP databases, compare valuable computational tools used to predict antimicrobial activity and mechanisms of action, and highlight new machine learning approaches that can be employed to improve AMP activity to combat global antimicrobial resistance.
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Affiliation(s)
- Ahmer Bin Hafeez
- Centre of Biotechnology and Microbiology, University of Peshawar, Peshawar 25120, Pakistan;
| | - Xukai Jiang
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; (X.J.); (P.J.B.)
- National Glycoengineering Research Center, Shandong University, Qingdao 266237, China
| | - Phillip J. Bergen
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; (X.J.); (P.J.B.)
| | - Yan Zhu
- Infection and Immunity Program, Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia; (X.J.); (P.J.B.)
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The Biology of Colicin M and Its Orthologs. Antibiotics (Basel) 2021; 10:antibiotics10091109. [PMID: 34572691 PMCID: PMC8469651 DOI: 10.3390/antibiotics10091109] [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: 07/29/2021] [Revised: 09/06/2021] [Accepted: 09/09/2021] [Indexed: 12/24/2022] Open
Abstract
The misuse of antibiotics during the last decades led to the emergence of multidrug resistant pathogenic bacteria. This phenomenon constitutes a major public health issue. Consequently, the discovery of new antibacterials in the short term is crucial. Colicins, due to their antibacterial properties, thus constitute good candidates. These toxin proteins, produced by E. coli to kill enteric relative competitors, exhibit cytotoxicity through ionophoric activity or essential macromolecule degradation. Among the 25 colicin types known to date, colicin M (ColM) is the only one colicin interfering with peptidoglycan biosynthesis. Accordingly, ColM develops its lethal activity in E. coli periplasm by hydrolyzing the last peptidoglycan precursor, lipid II, into two dead-end products, thereby leading to cell lysis. Since the discovery of its unusual mode of action, several ColM orthologs have also been identified based on sequence alignments; all of the characterized ColM-like proteins display the same enzymatic activity of lipid II degradation and narrow antibacterial spectra. This publication aims at being an exhaustive review of the current knowledge on this new family of antibacterial enzymes as well as on their potential use as food preservatives or therapeutic agents.
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14
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Li Y, Han Y, Zeng Z, Li W, Feng S, Cao W. Discovery and Bioactivity of the Novel Lasso Peptide Microcin Y. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:8758-8767. [PMID: 34314160 DOI: 10.1021/acs.jafc.1c02659] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Lasso peptides, a class of ribosomally synthesized and post-translationally modified peptides (RiPPs) secreted by bacteria, have antimicrobial activity. Here, a novel lasso peptide, microcin Y (MccY), was discovered and characterized. The gene cluster for MccY synthesis was cloned for expression in Escherichia coli. This peptide was purified by HPLC and characterized by Q-TOF. MIC assays showed that some Bacillus, Staphylococcus, Pseudomonas, Shigella, and Salmonella strains were sensitive to MccY. Interestingly, Salmonellatyphimurium and Salmonella infantis were efficiently inhibited by MccY, while they were not affected by MccJ25, a lasso peptide that has antibacterial effects on many Salmonella strains. Furthermore, MccY-resistant strains of S. typhimurium were screened, and mutations were found in FhuA and SbmA, indicating the importance of these transporters for MccY absorption. This novel peptide can greatly broaden the antimicrobial spectrum of MccJ25 in Salmonella and is expected to be used in food preservation and animal feed additive areas.
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Affiliation(s)
- Yu Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Yu Han
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Zhiwei Zeng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Wenjing Li
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Saixiang Feng
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, People's Republic of China
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, South China Agricultural University, Guangzhou 510642, People's Republic of China
| | - Weisheng Cao
- College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
- Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou 510642, People's Republic of China
- Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China
- National and Regional Joint Engineering Laboratory for Medicament of Zoonosis Prevention and Control, South China Agricultural University, Guangzhou 510642, People's Republic of China
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Johnstone BA, Christie MP, Morton CJ, Parker MW. X-ray crystallography shines a light on pore-forming toxins. Methods Enzymol 2021; 649:1-46. [PMID: 33712183 DOI: 10.1016/bs.mie.2021.01.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A common form of cellular attack by pathogenic bacteria is to secrete pore-forming toxins (PFTs). Capable of forming transmembrane pores in various biological membranes, PFTs have also been identified in a diverse range of other organisms such as sea anemones, earthworms and even mushrooms and trees. The mechanism of pore formation by PFTs is associated with substantial conformational changes in going from the water-soluble to transmembrane states of the protein. The determination of the crystal structures for numerous PFTs has shed much light on our understanding of these proteins. Other than elucidating the atomic structural details of PFTs and the conformational changes that must occur for pore formation, crystal structures have revealed structural homology that has led to the discovery of new PFTs and new PFT families. Here we review some key crystallographic results together with complimentary approaches for studying PFTs. We discuss how these studies have impacted our understanding of PFT function and guided research into biotechnical applications.
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Affiliation(s)
- Bronte A Johnstone
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Michelle P Christie
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Craig J Morton
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia
| | - Michael W Parker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, Australia; St. Vincent's Institute of Medical Research, Fitzroy, VIC, Australia.
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A Toxic Environment: a Growing Understanding of How Microbial Communities Affect Escherichia coli O157:H7 Shiga Toxin Expression. Appl Environ Microbiol 2020; 86:AEM.00509-20. [PMID: 32358004 DOI: 10.1128/aem.00509-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) strains, including E. coli O157:H7, cause severe illness in humans due to the production of Shiga toxin (Stx) and other virulence factors. Because Stx is coregulated with lambdoid prophage induction, its expression is especially susceptible to environmental cues. Infections with Stx-producing E. coli can be difficult to model due to the wide range of disease outcomes: some infections are relatively mild, while others have serious complications. Probiotic organisms, members of the gut microbiome, and organic acids can depress Stx production, in many cases by inhibiting the growth of EHEC strains. On the other hand, the factors currently known to amplify Stx act via their effect on the stx-converting phage. Here, we characterize two interactive mechanisms that increase Stx production by O157:H7 strains: first, direct interactions with phage-susceptible E. coli, and second, indirect amplification by secreted factors. Infection of susceptible strains by the stx-converting phage can expand the Stx-producing population in a human or animal host, and phage infection has been shown to modulate virulence in vitro and in vivo Acellular factors, particularly colicins and microcins, can kill O157:H7 cells but may also trigger Stx expression in the process. Colicins, microcins, and other bacteriocins have diverse cellular targets, and many such molecules remain uncharacterized. The identification of additional Stx-amplifying microbial interactions will improve our understanding of E. coli O157:H7 infections and help elucidate the intricate regulation of pathogenicity in EHEC strains.
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CbrA Mediates Colicin M Resistance in Escherichia coli through Modification of Undecaprenyl-Phosphate-Linked Peptidoglycan Precursors. J Bacteriol 2020; 202:JB.00436-20. [PMID: 32958631 DOI: 10.1128/jb.00436-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023] Open
Abstract
Colicin M is an enzymatic bacteriocin produced by some Escherichia coli strains which provokes cell lysis of competitor strains by hydrolysis of the cell wall peptidoglycan undecaprenyl-PP-MurNAc(-pentapeptide)-GlcNAc (lipid II) precursor. The overexpression of a gene, cbrA (formerly yidS), was shown to protect E. coli cells from the deleterious effects of this colicin, but the underlying resistance mechanism was not established. We report here that a major structural modification of the undecaprenyl-phosphate carrier lipid and of its derivatives occurred in membranes of CbrA-overexpressing cells, which explains the acquisition of resistance toward this bacteriocin. Indeed, a main fraction of these lipids, including the lipid II peptidoglycan precursor, now displayed a saturated isoprene unit at the α-position, i.e., the unit closest to the colicin M cleavage site. Only unsaturated forms of these lipids were normally detectable in wild-type cells. In vitro and in vivo assays showed that colicin M did not hydrolyze α-saturated lipid II, clearly identifying this substrate modification as the resistance mechanism. These saturated forms of undecaprenyl-phosphate and lipid II remained substrates of the different enzymes participating in peptidoglycan biosynthesis and carrier lipid recycling, allowing this colicin M-resistance mechanism to occur without affecting this essential pathway.IMPORTANCE Overexpression of the chromosomal cbrA gene allows E. coli to resist colicin M (ColM), a bacteriocin specifically hydrolyzing the undecaprenyl-PP-MurNAc(-pentapeptide)-GlcNAc (lipid II) peptidoglycan precursor of targeted cells. This resistance results from a CbrA-dependent modification of the precursor structure, i.e., reduction of the α-isoprenyl bond of C55-carrier lipid moiety that is proximal to ColM cleavage site. This modification, observed here for the first time in eubacteria, annihilates the ColM activity without affecting peptidoglycan biogenesis. These data, which further increase our knowledge of the substrate specificity of this colicin, highlight the capability of E. coli to generate reduced forms of C55-carrier lipid and its derivatives. Whether the function of this modification is only relevant with respect to ColM resistance is now questioned.
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Jansen KB, Inns PG, Housden NG, Hopper JTS, Kaminska R, Lee S, Robinson CV, Bayley H, Kleanthous C. Bifurcated binding of the OmpF receptor underpins import of the bacteriocin colicin N into Escherichia coli. J Biol Chem 2020; 295:9147-9156. [PMID: 32398259 PMCID: PMC7335789 DOI: 10.1074/jbc.ra120.013508] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/04/2020] [Indexed: 11/14/2022] Open
Abstract
Colicins are Escherichia coli-specific bacteriocins that translocate across the outer bacterial membrane by a poorly understood mechanism. Group A colicins typically parasitize the proton-motive force-linked Tol system in the inner membrane via porins after first binding an outer membrane protein receptor. Recent studies have suggested that the pore-forming group A colicin N (ColN) instead uses lipopolysaccharide as a receptor. Contrary to this prevailing view, using diffusion-precipitation assays, native state MS, isothermal titration calorimetry, single-channel conductance measurements in planar lipid bilayers, and in vivo fluorescence imaging, we demonstrate here that ColN uses OmpF both as its receptor and translocator. This dual function is achieved by ColN having multiple distinct OmpF-binding sites, one located within its central globular domain and another within its disordered N terminus. We observed that the ColN globular domain associates with the extracellular surface of OmpF and that lipopolysaccharide (LPS) enhances this binding. Approximately 90 amino acids of ColN then translocate through the porin, enabling the ColN N terminus to localize within the lumen of an OmpF subunit from the periplasmic side of the membrane, a binding mode reminiscent of that observed for the nuclease colicin E9. We conclude that bifurcated engagement of porins is intrinsic to the import mechanism of group A colicins.
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Affiliation(s)
| | | | | | | | - Renata Kaminska
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Sejeong Lee
- Chemistry Research laboratory, University of Oxford, Oxford, United Kingdom
| | - Carol V Robinson
- Chemistry Research laboratory, University of Oxford, Oxford, United Kingdom
| | - Hagan Bayley
- Chemistry Research laboratory, University of Oxford, Oxford, United Kingdom
| | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
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Marutani-Hert M, Hert AP, Tudor-Nelson SM, Preston JF, Minsavage GV, Stall RE, Roberts PD, Timilsina S, Hurlbert JC, Jones JB. Characterization of three novel genetic loci encoding bacteriocins associated with Xanthomonas perforans. PLoS One 2020; 15:e0233301. [PMID: 32469926 PMCID: PMC7259588 DOI: 10.1371/journal.pone.0233301] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 05/02/2020] [Indexed: 11/18/2022] Open
Abstract
Bacterial spot is a destructive disease of tomato in Florida that prior to the early 1990s was caused by Xanthomonas euvesicatoria. X. perforans was first identified in Florida in 1991 and by 2006 was the only xanthomonad associated with bacterial spot disease in tomato. The ability of an X. perforans strain to outcompete X. euvesicatoria both in vitro and in vivo was at least in part associated with the production of three bacteriocins designated Bcn-A, Bcn-B, and Bcn-C. The objective of this study was to characterize the genetic determinants of these bacteriocins. Bcn-A activity was confined to one locus consisting of five ORFs of which three (ORFA, ORF2 and ORF4) were required for bacteriocin activity. The fifth ORF is predicted to encode an immunity protein to Bcn-A based on in vitro and in vivo assays. The first ORF encodes Bcn-A, a 1,398 amino acid protein, which bioinformatic analysis predicts to be a member of the RHS family of toxins. Based on results of homology modeling, we hypothesize that the amino terminus of Bcn-A interacts with a protein in the outer membrane of X. euvesicatoria. The carboxy terminus of the protein may interact with an as yet unknown protein(s) and puncture the X. euvesicatoria membrane, thereby delivering the accessory proteins into the target and causing cell death. Bcn-A appears to be activated upon secretion based on cell fractionation assays. The other two loci were each shown to be single ORFs encoding Bcn-B and Bcn-C. Both gene products possess homology toward known proteases. Proteinase activity for both Bcn-B and Bcn-C was confirmed using a milk agar assay. Bcn-B is predicted to be an ArgC-like serine protease, which was confirmed by PMSF inhibition of proteolytic activity, whereas Bcn-C has greater than 50% amino acid sequence identity to two zinc metalloproteases.
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Affiliation(s)
- Mizuri Marutani-Hert
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Aaron P. Hert
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Simone M. Tudor-Nelson
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - James F. Preston
- Microbiology and Cell Sciences, University of Florida, Gainesville, Florida, United States of America
| | - Gerald V. Minsavage
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Robert E. Stall
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
| | - Pamela D. Roberts
- Southwest Florida Research and Education Center, University of Florida, Immokalee, Florida, United States of America
| | - Sujan Timilsina
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
- * E-mail: (JBJ); (JCH); (ST)
| | - Jason C. Hurlbert
- College of Arts and Sciences, Winthrop University, Rock Hill, South Carolina, United States of America
- * E-mail: (JBJ); (JCH); (ST)
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida, United States of America
- * E-mail: (JBJ); (JCH); (ST)
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Simons A, Alhanout K, Duval RE. Bacteriocins, Antimicrobial Peptides from Bacterial Origin: Overview of Their Biology and Their Impact against Multidrug-Resistant Bacteria. Microorganisms 2020; 8:E639. [PMID: 32349409 PMCID: PMC7285073 DOI: 10.3390/microorganisms8050639] [Citation(s) in RCA: 196] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/16/2020] [Accepted: 04/22/2020] [Indexed: 12/18/2022] Open
Abstract
Currently, the emergence and ongoing dissemination of antimicrobial resistance among bacteria are critical health and economic issue, leading to increased rates of morbidity and mortality related to bacterial infections. Research and development for new antimicrobial agents is currently needed to overcome this problem. Among the different approaches studied, bacteriocins seem to be a promising possibility. These molecules are peptides naturally synthesized by ribosomes, produced by both Gram-positive bacteria (GPB) and Gram-negative bacteria (GNB), which will allow these bacteriocin producers to survive in highly competitive polymicrobial environment. Bacteriocins exhibit antimicrobial activity with variable spectrum depending on the peptide, which may target several bacteria. Already used in some areas such as agro-food, bacteriocins may be considered as interesting candidates for further development as antimicrobial agents used in health contexts, particularly considering the issue of antimicrobial resistance. The aim of this review is to present an updated global report on the biology of bacteriocins produced by GPB and GNB, as well as their antibacterial activity against relevant bacterial pathogens, and especially against multidrug-resistant bacteria.
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Affiliation(s)
- Alexis Simons
- Université de Lorraine, CNRS, L2CM, F-54000 Nancy, France
- Institut Micalis, équipe Bactéries Pathogènes et Santé, Faculté de Pharmacie, Université Paris-Saclay—INRAE—AgroParisTech, 92296 Châtenay-Malabry, France
| | - Kamel Alhanout
- Université de Lorraine, CNRS, L2CM, F-54000 Nancy, France
| | - Raphaël E. Duval
- Université de Lorraine, CNRS, L2CM, F-54000 Nancy, France
- ABC Platform, Faculté de Pharmacie, F-54505 Vandœuvre-lès-Nancy, France
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Paquette SJ, Reuter T. Properties of an Antimicrobial Molecule Produced by an Escherichia coli Champion. Antibiotics (Basel) 2019; 9:E6. [PMID: 31877806 PMCID: PMC7168273 DOI: 10.3390/antibiotics9010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/03/2019] [Accepted: 12/18/2019] [Indexed: 11/17/2022] Open
Abstract
Over recent decades, the number and frequency of severe pathogen infections have been increasing. Pathogen mitigation strategies in human medicine or in livestock operations are vital to combat emerging arsenals of bacterial virulence and defense mechanisms. Since the emergence of antimicrobial resistance, the competitive nature of bacteria has been considered for the potential treatment or mitigation of pathogens. Previously, we identified a strong E. coli competitor with probiotic properties producing a diffusible antimicrobial molecule(s) that inhibited the growth of Shiga toxin-producing E. coli (STEC). Our current objective was to isolate and examine the properties of this antimicrobial molecule(s). Molecules were isolated by filter sterilization after 12 h incubation, and bacterial inhibition was compared to relevant controls. Isolated antimicrobial molecule(s) and controls were subjected to temperature, pH, or protease digestion treatments. Changes in inhibition properties were evaluated by comparing the incremental cell growth in the presence of treated and untreated antimicrobial molecule(s). No treatment affected the antimicrobial molecule(s) properties of STEC inhibition, suggesting that at least one molecule produced is an efficacious microcin. The molecule persistence to physiochemical and enzymatic treatments could open a wide window to technical industry-scale applications.
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Affiliation(s)
- Sarah-Jo Paquette
- Alberta Agriculture and Forestry, #100-5401 1st Ave. South, Lethbridge, AB T1J 4V6, Canada;
- Department of Biological Sciences, University of Lethbridge, 4401 University Drive West, Lethbridge, AB T1J 4V6, Canada
| | - Tim Reuter
- Alberta Agriculture and Forestry, #100-5401 1st Ave. South, Lethbridge, AB T1J 4V6, Canada;
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A Putative Microcin Amplifies Shiga Toxin 2a Production of Escherichia coli O157:H7. J Bacteriol 2019; 202:JB.00353-19. [PMID: 31611289 DOI: 10.1128/jb.00353-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 10/01/2019] [Indexed: 01/15/2023] Open
Abstract
Escherichia coli O157:H7 is a foodborne pathogen implicated in various multistate outbreaks. It encodes Shiga toxin on a prophage, and Shiga toxin production is linked to phage induction. An E. coli strain, designated 0.1229, that amplified Stx2a production when cocultured with E. coli O157:H7 strain PA2 was identified. Growth of PA2 in 0.1229 cell-free supernatants had a similar effect, even when supernatants were heated to 100°C for 10 min, but not after treatment with proteinase K. The secreted molecule was shown to use TolC for export and the TonB system for import. The genes sufficient for production of this molecule were localized to a 5.2-kb region of a 12.8-kb plasmid. This region was annotated, identifying hypothetical proteins, a predicted ABC transporter, and a cupin superfamily protein. These genes were identified and shown to be functional in two other E. coli strains, and bioinformatic analyses identified related gene clusters in similar and distinct bacterial species. These data collectively suggest that E. coli 0.1229 and other E. coli strains produce a microcin that induces the SOS response in target bacteria. Besides adding to the limited number of microcins known to be produced by E. coli, this study provides an additional mechanism by which stx 2a expression is increased in response to the gut microflora.IMPORTANCE How the gut microflora influences the progression of bacterial infections is only beginning to be understood. Antibiotics are counterindicated for E. coli O157:H7 infections, limiting treatment options. An increased understanding of how the gut microflora directs O157:H7 virulence gene expression may lead to additional treatment options. This work identified E. coli strains that enhance the production of Shiga toxin by O157:H7 through the secretion of a proposed microcin. Microcins are natural antimicrobial peptides that target specific species, can act as alternatives to antibiotics, and mediate microbial competition. This work demonstrates another mechanism by which non-O157 E. coli strains may increase Shiga toxin production and adds to our understanding of microcins, a group of antimicrobials less well understood than colicins.
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Grinter R, Lithgow T. The structure of the bacterial iron-catecholate transporter Fiu suggests that it imports substrates via a two-step mechanism. J Biol Chem 2019; 294:19523-19534. [PMID: 31712312 PMCID: PMC6926462 DOI: 10.1074/jbc.ra119.011018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 11/06/2019] [Indexed: 12/12/2022] Open
Abstract
The ferric iron uptake (Fiu) transporter from Escherichia coli functions in the transport of iron–catecholate complexes across the bacterial outer membrane, providing the bacterium with iron, which is essential for growth. Recently it has become clear that Fiu also represents a liability for E. coli because its activity allows import of antimicrobial compounds that mimic catecholate. This inadvertent import suggests the potential utility of antimicrobial catechol siderophore mimetics in managing bacterial infections. However, to fully exploit these compounds, a detailed understanding of the mechanism of transport through Fiu and related transporters is required. To address this question, we determined the crystal structure of Fiu at 2.1–2.9 Å and analyzed its function in E. coli. Through analysis of the Fiuo crystal structure, in combination with in silico docking and mutagenesis, we provide insight into how Fiu and related transporters bind catecholate in a surface-exposed cavity. Moreover, through determination of the structure of Fiu in multiple crystal states, we revealed the presence of a large, selectively gated cavity in the interior of this transporter. This chamber is large enough to accommodate the Fiu substrate and may allow import of substrates via a two-step mechanism. This would avoid channel formation through the transporter and inadvertent import of toxic molecules. As Fiu and its homologs are the targets of substrate-mimicking antibiotics, these results may assist in the development of these compounds.
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Affiliation(s)
- Rhys Grinter
- School of Biological Sciences, Monash University, Clayton, 3800 Victoria, Australia .,Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia
| | - Trevor Lithgow
- Infection and Immunity Program, Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, 3800 Victoria, Australia
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24
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Baquero F, Lanza VF, Baquero MR, Del Campo R, Bravo-Vázquez DA. Microcins in Enterobacteriaceae: Peptide Antimicrobials in the Eco-Active Intestinal Chemosphere. Front Microbiol 2019; 10:2261. [PMID: 31649628 PMCID: PMC6795089 DOI: 10.3389/fmicb.2019.02261] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/17/2019] [Indexed: 12/31/2022] Open
Abstract
Microcins are low-molecular-weight, ribosomally produced, highly stable, bacterial-inhibitory molecules involved in competitive, and amensalistic interactions between Enterobacteriaceae in the intestine. These interactions take place in a highly complex chemical landscape, the intestinal eco-active chemosphere, composed of chemical substances that positively or negatively influence bacterial growth, including those originated from nutrient uptake, and those produced by the action of the human or animal host and the intestinal microbiome. The contribution of bacteria results from their effect on the host generated molecules, on food and digested food, and organic substances from microbial origin, including from bacterial degradation. Here, we comprehensively review the main chemical substances present in the human intestinal chemosphere, particularly of those having inhibitory effects on microorganisms. With this background, and focusing on Enterobacteriaceae, the most relevant human pathogens from the intestinal microbiota, the microcin’s history and classification, mechanisms of action, and mechanisms involved in microcin’s immunity (in microcin producers) and resistance (non-producers) are reviewed. Products from the chemosphere likely modulate the ecological effects of microcin activity. Several cross-resistance mechanisms are shared by microcins, colicins, bacteriophages, and some conventional antibiotics, which are expected to produce cross-effects. Double-microcin-producing strains (such as microcins MccM and MccH47) have been successfully used for decades in the control of pathogenic gut organisms. Microcins are associated with successful gut colonization, facilitating translocation and invasion, leading to bacteremia, and urinary tract infections. In fact, Escherichia coli strains from the more invasive phylogroups (e.g., B2) are frequently microcinogenic. A publicly accessible APD3 database http://aps.unmc.edu/AP/ shows particular genes encoding microcins in 34.1% of E. coli strains (mostly MccV, MccM, MccH47, and MccI47), and much less in Shigella and Salmonella (<2%). Some 4.65% of Klebsiella pneumoniae are microcinogenic (mostly with MccE492), and even less in Enterobacter or Citrobacter (mostly MccS). The high frequency and variety of microcins in some Enterobacteriaceae indicate key ecological functions, a notion supported by their dominance in the intestinal microbiota of biosynthetic gene clusters involved in the synthesis of post-translationally modified peptide microcins.
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Affiliation(s)
- Fernando Baquero
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
| | - Val F Lanza
- Bioinformatics Unit, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
| | - Maria-Rosario Baquero
- Department of Microbiology, Alfonso X El Sabio University, Villanueva de la Cañada, Spain
| | - Rosa Del Campo
- Department of Microbiology, Ramón y Cajal University Hospital, Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
| | - Daniel A Bravo-Vázquez
- Department of Microbiology, Alfonso X El Sabio University, Villanueva de la Cañada, Spain
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25
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Impact of FiuA Outer Membrane Receptor Polymorphism on the Resistance of Pseudomonas aeruginosa toward Peptidoglycan Lipid II-Targeting PaeM Pyocins. J Bacteriol 2019; 201:JB.00164-19. [PMID: 30988031 DOI: 10.1128/jb.00164-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Accepted: 04/04/2019] [Indexed: 12/29/2022] Open
Abstract
Certain Pseudomonas aeruginosa strains produce a homolog of colicin M, namely, PaeM, that specifically inhibits peptidoglycan biosynthesis of susceptible P. aeruginosa strains by hydrolyzing the lipid II intermediate precursor. Two variants of this pyocin were identified whose sequences mainly differed in the N-terminal protein moiety, i.e., the region involved in the binding to the FiuA outer membrane receptor and translocation into the periplasm. The antibacterial activity of these two variants, PaeM1 and PaeM2, was tested against various P. aeruginosa strains comprising reference strains PAO1 and PA14, PaeM-producing strains, and 60 clinical isolates. Seven of these strains, including PAO1, were susceptible to only one variant (2 to PaeM1 and 5 to PaeM2), and 11 were affected by both. The remaining strains, including PA14 and four PaeM1 producers, were resistant to both variants. The differences in the antibacterial spectra of the two PaeM homologs prompted us to investigate the molecular determinants allowing their internalization into P. aeruginosa cells, taking the PAO1 strain that is susceptible to PaeM2 but resistant to PaeM1 as the indicator strain. Heterologous expression of fiuA gene orthologs from different strains into PAO1, site-directed mutagenesis experiments, and construction of PaeM chimeric proteins provided evidence that the cell susceptibility and discrimination differences between the PaeM variants resulted from a polymorphism of both the pyocin and the outer membrane receptor FiuA. Moreover, we found that a third component, TonB1, a protein involved in iron transport in P. aeruginosa, working together with FiuA and the ExbB/ExbD complex, was directly implicated in this discrimination.IMPORTANCE Bacterial antibiotic resistance constitutes a threat to human health, imposing the need for identification of new targets and development of new strategies to fight multiresistant pathogens. Bacteriocins and other weapons that bacteria have themselves developed to kill competitors are therefore of great interest and a valuable source of inspiration for us. Attention was paid here to two variants of a colicin M homolog (PaeM) produced by certain strains of P. aeruginosa that inhibit the growth of their congeners by blocking cell wall peptidoglycan synthesis. Molecular determinants allowing recognition of these pyocins by the outer membrane receptor FiuA were identified, and a receptor polymorphism affecting the susceptibility of P. aeruginosa clinical strains was highlighted, providing new insights into the potential use of these pyocins as an alternative to antibiotics.
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26
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Chung LK, Raffatellu M. G.I. pros: Antimicrobial defense in the gastrointestinal tract. Semin Cell Dev Biol 2019; 88:129-137. [PMID: 29432952 PMCID: PMC6087682 DOI: 10.1016/j.semcdb.2018.02.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 01/11/2023]
Abstract
The gastrointestinal tract is a complex environment in which the host immune system interacts with a diverse array of microorganisms, both symbiotic and pathogenic. As such, mobilizing a rapid and appropriate antimicrobial response depending on the nature of each stimulus is crucial for maintaining the balance between homeostasis and inflammation in the gut. Here we focus on the mechanisms by which intestinal antimicrobial peptides regulate microbial communities during dysbiosis and infection. We also discuss classes of bacterial peptides that contribute to reducing enteric pathogen outgrowth. This review aims to provide a comprehensive overview on the interplay of diverse antimicrobial responses with enteric pathogens and the gut microbiota.
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Affiliation(s)
- Lawton K Chung
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego, La Jolla, CA, 92093-0704, United States
| | - Manuela Raffatellu
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego, La Jolla, CA, 92093-0704, United States; Chiba University-UC San Diego Center for Mucosal Immunology, Allergy, and Vaccines (CU-UCSD cMAV), La Jolla CA, United States.
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27
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Cheung-Lee WL, Parry ME, Jaramillo Cartagena A, Darst SA, Link AJ. Discovery and structure of the antimicrobial lasso peptide citrocin. J Biol Chem 2019; 294:6822-6830. [PMID: 30846564 DOI: 10.1074/jbc.ra118.006494] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/04/2019] [Indexed: 01/30/2023] Open
Abstract
We report the identification of citrocin, a 19-amino acid-long antimicrobial lasso peptide from the bacteria Citrobacter pasteurii and Citrobacter braakii We refactored the citrocin gene cluster and heterologously expressed it in Escherichia coli We determined citrocin's NMR structure in water and found that is reminiscent of that of microcin J25 (MccJ25), an RNA polymerase-inhibiting lasso peptide that hijacks the TonB-dependent transporter FhuA to gain entry into cells. Citrocin has moderate antimicrobial activity against E. coli and Citrobacter strains. We then performed an in vitro RNA polymerase (RNAP) inhibition assay using citrocin and microcin J25 against E. coli RNAP. Citrocin has a higher minimal inhibition concentration than microcin J25 does against E. coli but surprisingly is ∼100-fold more potent as an RNAP inhibitor. This suggests that citrocin uptake by E. coli is limited. We found that unlike MccJ25, citrocin's activity against E. coli relied on neither of the two proton motive force-linked systems, Ton and Tol-Pal, for transport across the outer membrane. The structure of citrocin contains a patch of positive charge consisting of Lys-5 and Arg-17. We performed mutagenesis on these residues and found that the R17Y construct was matured into a lasso peptide but no longer had activity, showing the importance of this side chain for antimicrobial activity. In summary, we heterologously expressed and structurally and biochemically characterized an antimicrobial lasso peptide, citrocin. Despite being similar to MccJ25 in sequence, citrocin has an altered activity profile and does not use the same outer-membrane transporter to enter susceptible cells.
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Affiliation(s)
| | | | - Alexis Jaramillo Cartagena
- the Laboratory of Molecular Biophysics and Tri-Institutional Training Program in Chemical Biology, Rockefeller University, New York, New York 10065
| | - Seth A Darst
- the Laboratory of Molecular Biophysics and Tri-Institutional Training Program in Chemical Biology, Rockefeller University, New York, New York 10065
| | - A James Link
- From the Departments of Chemical and Biological Engineering, .,Chemistry, and.,Molecular Biology Princeton University, Princeton, New Jersey 08544 and
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28
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Chang JW, Sato Y, Ogawa T, Arakawa T, Fukai S, Fushinobu S, Masaki H. Crystal structure of the central and the C-terminal RNase domains of colicin D implicated its translocation pathway through inner membrane of target cell. J Biochem 2018; 164:329-339. [PMID: 29905832 DOI: 10.1093/jb/mvy056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 06/10/2018] [Indexed: 12/18/2022] Open
Abstract
Colicins are protein toxins produced by and toxic to Escherichia coli strains. Colicin D consists of an N-terminal domain (NTD), central domain (CD) and C-terminal RNase domain (CRD). The cognate immunity protein, ImmD, is co-synthesized in producer cells to block the toxic tRNase activity of the CRD. Previous studies have reported the crystal structure of CRD/ImmD complex. Colicin D hijacks the surface receptor FepA and the energy transducer TonB system using the NTD for translocation across the outer membrane of the target cells. The CD is required for endoproteolytic processing and the translocation of CRD across the inner membrane, and the membrane-associated protease FtsH and the signal peptidase LepB are exploited in this process. Although several regions of the CD have been identified in interactions with the hijacked inner membrane system or immunity protein, the structural basis of the CD is unknown. In this study, we determined the crystal structure of colicin D, containing both the CD and CRD. The full-length colicin D/ImmD heterodimer structure was built by superimposing the CD-CRD structure with the previously determined partial structures. The overall translocation process of colicin D, including the interaction between CD and LepB, is discussed.
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Affiliation(s)
- Jung-Wei Chang
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Yusuke Sato
- Synchrotron Radiation Research Organization, The University of Tokyo, Tokyo, Japan.,Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
| | - Tetsuhiro Ogawa
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Takatoshi Arakawa
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Shuya Fukai
- Synchrotron Radiation Research Organization, The University of Tokyo, Tokyo, Japan.,Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
| | - Shinya Fushinobu
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
| | - Haruhiko Masaki
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.,Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, Japan
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29
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Braun V. The Outer Membrane Took Center Stage. Annu Rev Microbiol 2018; 72:1-24. [PMID: 30200853 DOI: 10.1146/annurev-micro-090817-062156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
My interest in membranes was piqued during a lecture series given by one of the founders of molecular biology, Max Delbrück, at Caltech, where I spent a postdoctoral year to learn more about protein chemistry. That general interest was further refined to my ultimate research focal point-the outer membrane of Escherichia coli-through the influence of the work of Wolfhard Weidel, who discovered the murein (peptidoglycan) layer and biochemically characterized the first phage receptors of this bacterium. The discovery of lipoprotein bound to murein was completely unexpected and demonstrated that the protein composition of the outer membrane and the structure and function of proteins could be unraveled at a time when nothing was known about outer membrane proteins. The research of my laboratory over the years covered energy-dependent import of proteinaceous toxins and iron chelates across the outer membrane, which does not contain an energy source, and gene regulation by iron, including transmembrane transcriptional regulation.
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Affiliation(s)
- Volkmar Braun
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany;
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30
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Raffatellu M. Learning from bacterial competition in the host to develop antimicrobials. Nat Med 2018; 24:1097-1103. [DOI: 10.1038/s41591-018-0145-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 05/24/2018] [Accepted: 07/03/2018] [Indexed: 02/07/2023]
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Abstract
The outer membrane (OM) excludes antibiotics such as vancomycin that kill gram-positive bacteria, and so is a major contributor to multidrug resistance in gram-negative bacteria. Yet, the OM is readily bypassed by protein bacteriocins, which are toxins released by bacteria to kill their neighbors during competition for resources. Discovered over 60 y ago, it has been a mystery how these proteins cross the OM to deliver their toxic payload. We have discovered how the bacteriocin pyocin S2 (pyoS2), which degrades DNA, enters Pseudomonas aeruginosa cells. PyoS2 tricks the iron transporter FpvAI into transporting it across the OM by a process that is remarkably similar to that used by its endogenous ligand, the siderophore ferripyoverdine. Unlike their descendants, mitochondria and plastids, bacteria do not have dedicated protein import systems. However, paradoxically, import of protein bacteriocins, the mechanisms of which are poorly understood, underpins competition among pathogenic and commensal bacteria alike. Here, using X-ray crystallography, isothermal titration calorimetry, confocal fluorescence microscopy, and in vivo photoactivatable cross-linking of stalled translocation intermediates, we demonstrate how the iron transporter FpvAI in the opportunistic pathogen Pseudomonas aeruginosa is hijacked to translocate the bacteriocin pyocin S2 (pyoS2) across the outer membrane (OM). FpvAI is a TonB-dependent transporter (TBDT) that actively imports the small siderophore ferripyoverdine (Fe-Pvd) by coupling to the proton motive force (PMF) via the inner membrane (IM) protein TonB1. The crystal structure of the N-terminal domain of pyoS2 (pyoS2NTD) bound to FpvAI (Kd = 240 pM) reveals that the pyocin mimics Fe-Pvd, inducing the same conformational changes in the receptor. Mimicry leads to fluorescently labeled pyoS2NTD being imported into FpvAI-expressing P. aeruginosa cells by a process analogous to that used by bona fide TBDT ligands. PyoS2NTD induces unfolding by TonB1 of a force-labile portion of the plug domain that normally occludes the central channel of FpvAI. The pyocin is then dragged through this narrow channel following delivery of its own TonB1-binding epitope to the periplasm. Hence, energized nutrient transporters in bacteria also serve as rudimentary protein import systems, which, in the case of FpvAI, results in a protein antibiotic 60-fold bigger than the transporter’s natural substrate being translocated across the OM.
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32
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Lim JA, Hong J, Kim J, Heu S, Roh E. OmpF of Pectobacterium carotovorum subsp. carotovorum Pcc3 is required for carocin D sensitivity. FEMS Microbiol Lett 2016; 363:fnw258. [PMID: 27915254 DOI: 10.1093/femsle/fnw258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 04/04/2016] [Accepted: 11/21/2016] [Indexed: 11/14/2022] Open
Abstract
Carocin D is a bacteriocin produced by Pectobacterium carotovorum subsp. carotovorum Pcc21. Carocin D inhibits the growth of P carotovorum subsp. carotovorum and closely related strains. Pectobacterium carotovorum subsp. carotovorum is a causative bacterium for soft rot disease and leads to severe economic losses. Bacteriocins recognize and interact with a specific membrane protein of target bacteria as a receptor. To identify the receptor responsible for carocin D recognition, mutants that underwent a phenotypic change from carocin D sensitivity to carocin D insensitivity were screened. Based on Tn5 insertions, carocin D sensitivity was dependent on expression of the outer membrane protein OmpF. The insensitivity of the mutant (Pcc3MR) to carocin D was complemented with ompF from carocin D-sensitive strains, not from carocin D-resistant strains. The selectivity between sensitive and resistant strains could be attributed to variation in OmpFs in the cell-surface-exposed regions. Based on sequence analysis and complementation assays, it appears that carocin D uses OmpF as a receptor and is translocated by the TonB system. According to previously reported translocation mechanisms of colicins, OmpF works along with the TolA system rather than the TonB system. Therefore, the current findings suggest that carocin D is imported by a unique colicin-like bacteriocin translocation system.
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Affiliation(s)
- Jeong-A Lim
- Microbial Safety Team, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Republic of Korea
| | - Jisoo Hong
- Microbial Safety Team, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Republic of Korea
| | - Jonguk Kim
- Microbial Safety Team, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Republic of Korea
| | - Sunggi Heu
- Microbial Safety Team, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Republic of Korea
| | - Eunjung Roh
- Microbial Safety Team, National Institute of Agricultural Sciences, Rural Development Administration, Wanju-gun 55365, Republic of Korea
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33
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Chérier D, Giacomucci S, Patin D, Bouhss A, Touzé T, Blanot D, Mengin-Lecreulx D, Barreteau H. Pectocin M1 (PcaM1) Inhibits Escherichia coli Cell Growth and Peptidoglycan Biosynthesis through Periplasmic Expression. Antibiotics (Basel) 2016; 5:antibiotics5040036. [PMID: 27740593 PMCID: PMC5187517 DOI: 10.3390/antibiotics5040036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 09/14/2016] [Accepted: 09/23/2016] [Indexed: 11/20/2022] Open
Abstract
Colicins are bacterial toxins produced by some Escherichia coli strains. They exhibit either enzymatic or pore-forming activity towards a very limited number of bacterial species, due to the high specificity of their reception and translocation systems. Yet, we succeeded in making the colicin M homologue from Pectobacterium carotovorum, pectocin M1 (PcaM1), capable of inhibiting E. coli cell growth by bypassing these reception and translocation steps. This goal was achieved through periplasmic expression of this pectocin. Indeed, when appropriately addressed to the periplasm of E. coli, this pectocin could exert its deleterious effects, i.e., the enzymatic degradation of the peptidoglycan lipid II precursor, which resulted in the arrest of the biosynthesis of this essential cell wall polymer, dramatic morphological changes and, ultimately, cell lysis. This result leads to the conclusion that colicin M and its various orthologues constitute powerful antibacterial molecules able to kill any kind of bacterium, once they can reach their lipid II target. They thus have to be seriously considered as promising alternatives to antibiotics.
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Affiliation(s)
- Dimitri Chérier
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
| | - Sean Giacomucci
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
| | - Delphine Patin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
| | - Ahmed Bouhss
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
| | - Thierry Touzé
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
| | - Didier Blanot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
| | - Dominique Mengin-Lecreulx
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
| | - Hélène Barreteau
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France.
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Roces C, Rodríguez A, Martínez B. Cell Wall-active Bacteriocins and Their Applications Beyond Antibiotic Activity. Probiotics Antimicrob Proteins 2016; 4:259-72. [PMID: 26782186 DOI: 10.1007/s12602-012-9116-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microorganisms synthesize several compounds with antimicrobial activity in order to compete or defend themselves against others and ensure their survival. In this line, the cell wall is a major protective barrier whose integrity is essential for many vital bacterial processes. Probably for this reason, it represents a 'hot spot' as a target for many antibiotics and antimicrobial peptides such as bacteriocins. Bacteriocins have largely been recognized by their pore-forming ability that collapses the selective permeability of the cytoplasmic membrane. However, in the last few years, many bacteriocins have been shown to inhibit cell wall biosyntheis alone, or in a concerted action with pore formation like nisin. Examples of cell wall-active bacteriocins are found in both Gram-negative and Gram-positive bacteria and include a wide diversity of structures such as nisin-like and mersacidin-like lipid II-binding bacteriocins, two-peptide lantibiotics, and non-modified bacteriocins. In this review, we summarize the current knowledge on these antimicrobial peptides as well as the role, composition, and biosynthesis of the bacterial cell wall as their target. Moreover, even though bacteriocins have been a matter of interest as natural food antimicrobials, we propose them as suitable tools to provide new means to improve biotechnologically relevant microorganisms.
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Affiliation(s)
- Clara Roces
- DairySafe Group, Department of Technology and Biotechnology of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n., 33300, Villaviciosa, Asturias, Spain
| | - Ana Rodríguez
- DairySafe Group, Department of Technology and Biotechnology of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n., 33300, Villaviciosa, Asturias, Spain
| | - Beatriz Martínez
- DairySafe Group, Department of Technology and Biotechnology of Dairy Products, Instituto de Productos Lácteos de Asturias (IPLA-CSIC), Paseo Río Linares s/n., 33300, Villaviciosa, Asturias, Spain.
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Networks of energetic and metabolic interactions define dynamics in microbial communities. Proc Natl Acad Sci U S A 2015; 112:15450-5. [PMID: 26621749 DOI: 10.1073/pnas.1506034112] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Microorganisms form diverse communities that have a profound impact on the environment and human health. Recent technological advances have enabled elucidation of community diversity at high resolution. Investigation of microbial communities has revealed that they often contain multiple members with complementing and seemingly redundant metabolic capabilities. An understanding of the communal impacts of redundant metabolic capabilities is currently lacking; specifically, it is not known whether metabolic redundancy will foster competition or motivate cooperation. By investigating methanogenic populations, we identified the multidimensional interspecies interactions that define composition and dynamics within syntrophic communities that play a key role in the global carbon cycle. Species-specific genomes were extracted from metagenomic data using differential coverage binning. We used metabolic modeling leveraging metatranscriptomic information to reveal and quantify a complex intertwined system of syntrophic relationships. Our results show that amino acid auxotrophies create additional interdependencies that define community composition and control carbon and energy flux through the system while simultaneously contributing to overall community robustness. Strategic use of antimicrobials further reinforces this intricate interspecies network. Collectively, our study reveals the multidimensional interactions in syntrophic communities that promote high species richness and bolster community stability during environmental perturbations.
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Mora L, Moncoq K, England P, Oberto J, de Zamaroczy M. The Stable Interaction Between Signal Peptidase LepB of Escherichia coli and Nuclease Bacteriocins Promotes Toxin Entry into the Cytoplasm. J Biol Chem 2015; 290:30783-96. [PMID: 26499796 DOI: 10.1074/jbc.m115.691907] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 01/13/2023] Open
Abstract
LepB is a key membrane component of the cellular secretion machinery, which releases secreted proteins into the periplasm by cleaving the inner membrane-bound leader. We showed that LepB is also an essential component of the machinery hijacked by the tRNase colicin D for its import. Here we demonstrate that this non-catalytic activity of LepB is to promote the association of the central domain of colicin D with the inner membrane before the FtsH-dependent proteolytic processing and translocation of the toxic tRNase domain into the cytoplasm. The novel structural role of LepB results in a stable interaction with colicin D, with a stoichiometry of 1:1 and a nanomolar Kd determined in vitro. LepB provides a chaperone-like function for the penetration of several nuclease-type bacteriocins into target cells. The colicin-LepB interaction is shown to require only a short peptide sequence within the central domain of these bacteriocins and to involve residues present in the short C-terminal Box E of LepB. Genomic screening identified the conserved LepB binding motif in colicin-like ORFs from 13 additional bacterial species. These findings establish a new paradigm for the functional adaptability of an essential inner-membrane enzyme.
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Affiliation(s)
- Liliana Mora
- From the Institut de Biologie Physico-Chimique, CNRS, FRE 3630 (UPR 9073), 75005 Paris, France
| | - Karine Moncoq
- Institut de Biologie Physico-Chimique, CNRS, UMR 7099 (Université Paris 7-Diderot), 75005 Paris, France
| | - Patrick England
- Institut Pasteur, PFBMI, CNRS, UMR 3528, 75015 Paris, France, and
| | - Jacques Oberto
- Institute of Integrative Cellular Biology, CEA, CNRS (Université Paris 11), 91405 Orsay, France
| | - Miklos de Zamaroczy
- From the Institut de Biologie Physico-Chimique, CNRS, FRE 3630 (UPR 9073), 75005 Paris, France,
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Abstract
Research in Tübingen on bacterial cell walls began in 1951 and continues to this day. The studies over the decades reflect the development in the field, which was strongly influenced by the design of suitable biochemical and genetic methods used to unravel the highly complex envelope structure. At the beginning of this period, improper crude extraction and solubilization methods were employed in an attempt to isolate pure components. Nevertheless, progress was steady and culminated in major insights into the structure and function of individual cell wall components and the cell wall as a whole. The "cell wall" has various definitions. In this short overview, the term includes the cell wall of gram-positive bacteria in the strict sense, and also the outer membrane, the murein (peptidoglycan) and the outer membrane of gram-negative bacteria and the cytoplasmic membranes.
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Affiliation(s)
- Volkmar Braun
- Max Planck Institute for Developmental Biology, Department of Protein Evolution, Spemannstrasse 35, 72076 Tübingen, Germany.
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Abstract
The paper provides a short overview of three investigated bacterial protein toxins, colicin M (Cma) of Escherichia coli, pesticin (Pst) of Yersinia pestis and hemolysin (ShlAB) of Serratia marcescens. Cma and Pst are exceptional among colicins in that they kill bacteria by degrading the murein (peptidoglycan). Both are released into the medium and bind to specific receptor proteins in the outer membrane of sensitive E. coli cells. Subsequently they are translocated into the periplasm by an energy-consuming process using the proton motive force. For transmembrane translocation the colicins unfold and refold in the periplasm. In the case of Cma the FkpA peptidyl prolyl cis-trans isomerase/chaperone is required. ShlA is secreted and activated through ShlB in the outer membrane by a type Vb secretion mechanism.
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Abstract
ABSTRACT
Plasmids confer genetic information that benefits the bacterial cells containing them. In pathogenic bacteria, plasmids often harbor virulence determinants that enhance the pathogenicity of the bacterium. The ability to acquire iron in environments where it is limited, for instance the eukaryotic host, is a critical factor for bacterial growth. To acquire iron, bacteria have evolved specific iron uptake mechanisms. These systems are often chromosomally encoded, while those that are plasmid-encoded are rare. Two main plasmid types, ColV and pJM1, have been shown to harbor determinants that increase virulence by providing the cell with essential iron for growth. It is clear that these two plasmid groups evolved independently from each other since they do not share similarities either in the plasmid backbones or in the iron uptake systems they harbor. The siderophores aerobactin and salmochelin that are found on ColV plasmids fall in the hydroxamate and catechol group, respectively, whereas both functional groups are present in the anguibactin siderophore, the only iron uptake system found on pJM1-type plasmids. Besides siderophore-mediated iron uptake, ColV plasmids carry additional genes involved in iron metabolism. These systems include ABC transporters, hemolysins, and a hemoglobin protease. ColV- and pJM1-like plasmids have been shown to confer virulence to their bacterial host, and this trait can be completely ascribed to their encoded iron uptake systems.
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Sousa MÂB, Farias LDM, Oliveira PLD, Moreira JS, Apolônio ACM, Oliveira JS, Santoro MM, Mendes EN, Magalhães PP. Antagonistic activity expressed by Shigella sonnei: identification of a putative new bacteriocin. Mem Inst Oswaldo Cruz 2014; 108:724-9. [PMID: 24037194 PMCID: PMC3970690 DOI: 10.1590/0074-0276108062013008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 07/10/2013] [Indexed: 11/25/2022] Open
Abstract
Bacteriocins are antibacterial, proteinaceous substances that mediate microbial
dynamics. Bacteriocin production is a highly disseminated property among all
major lineages of bacteria, including Shigella. In this paper,
we addressed the purification and characterisation of a bacteriocin produced by
a Shigella sonnei strain (SS9) isolated from a child with acute
diarrhoea. The substance was purified through ammonium-sulphate precipitation
and sequential steps of chromatography. The intracellular fraction obtained at
75% ammonium sulphate maintained activity following exposure to pH values from
1-11 and storage at -80ºC for more than two years and was inactivated by high
temperatures and proteases. The molecular mass of the purified bacteriocin was
determined by mass spectrometry to be 18.56 kDa. The N-terminal sequence of the
bacteriocin did not match any other antibacterial proteins described. A putative
new bacteriocin produced by S. sonnei has been detected. This
bacteriocin may represent a newly described protein or a previously described
protein with a newly detected function. Considering that SS9 expresses
antagonism against other diarrhoeagenic bacteria, the bacteriocin may contribute
to S. sonnei virulence and is potentially applicable to either
preventing or controlling diarrhoeal disease.
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Kim YC, Tarr AW, Penfold CN. Colicin import into E. coli cells: a model system for insights into the import mechanisms of bacteriocins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1717-31. [PMID: 24746518 DOI: 10.1016/j.bbamcr.2014.04.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/04/2014] [Accepted: 04/06/2014] [Indexed: 01/03/2023]
Abstract
Bacteriocins are a diverse group of ribosomally synthesized protein antibiotics produced by most bacteria. They range from small lanthipeptides produced by lactic acid bacteria to much larger multi domain proteins of Gram negative bacteria such as the colicins from Escherichia coli. For activity bacteriocins must be released from the producing cell and then bind to the surface of a sensitive cell to instigate the import process leading to cell death. For over 50years, colicins have provided a working platform for elucidating the structure/function studies of bacteriocin import and modes of action. An understanding of the processes that contribute to the delivery of a colicin molecule across two lipid membranes of the cell envelope has advanced our knowledge of protein-protein interactions (PPI), protein-lipid interactions and the role of order-disorder transitions of protein domains pertinent to protein transport. In this review, we provide an overview of the arrangement of genes that controls the synthesis and release of the mature protein. We examine the uptake processes of colicins from initial binding and sequestration of binding partners to crossing of the outer membrane, and then discuss the translocation of colicins through the cell periplasm and across the inner membrane to their cytotoxic site of action. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Affiliation(s)
- Young Chan Kim
- School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, NG7 2UH, UK
| | - Alexander W Tarr
- School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, NG7 2UH, UK
| | - Christopher N Penfold
- School of Life Sciences, University of Nottingham, Queens Medical Centre, Nottingham, NG7 2UH, UK.
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Adediran J, Leatham-Jensen MP, Mokszycki ME, Frimodt-Møller J, Krogfelt KA, Kazmierczak K, Kenney LJ, Conway T, Cohen PS. An Escherichia coli Nissle 1917 missense mutant colonizes the streptomycin-treated mouse intestine better than the wild type but is not a better probiotic. Infect Immun 2014; 82:670-82. [PMID: 24478082 PMCID: PMC3911375 DOI: 10.1128/iai.01149-13] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/18/2013] [Indexed: 01/08/2023] Open
Abstract
Previously we reported that the streptomycin-treated mouse intestine selected for two different Escherichia coli MG1655 mutants with improved colonizing ability: nonmotile E. coli MG1655 flhDC deletion mutants that grew 15% faster in vitro in mouse cecal mucus and motile E. coli MG1655 envZ missense mutants that grew slower in vitro in mouse cecal mucus yet were able to cocolonize with the faster-growing flhDC mutants. The E. coli MG1655 envZ gene encodes a histidine kinase that is a member of the envZ-ompR two-component signal transduction system, which regulates outer membrane protein profiles. In the present investigation, the envZP41L gene was transferred from the intestinally selected E. coli MG1655 mutant to E. coli Nissle 1917, a human probiotic strain used to treat gastrointestinal infections. Both the E. coli MG1655 and E. coli Nissle 1917 strains containing envZP41L produced more phosphorylated OmpR than their parents. The E. coli Nissle 1917 strain containing envZP41L also became more resistant to bile salts and colicin V and grew 50% slower in vitro in mucus and 15% to 30% slower on several sugars present in mucus, yet it was a 10-fold better colonizer than E. coli Nissle 1917. However, E. coli Nissle 1917 envZP41L was not better at preventing colonization by enterohemorrhagic E. coli EDL933. The data can be explained according to our "restaurant" hypothesis for commensal E. coli strains, i.e., that they colonize the intestine as sessile members of mixed biofilms, obtaining the sugars they need for growth locally, but compete for sugars with invading E. coli pathogens planktonically.
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Affiliation(s)
- Jimmy Adediran
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island, USA
| | - Mary P. Leatham-Jensen
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island, USA
| | - Matthew E. Mokszycki
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island, USA
| | - Jakob Frimodt-Møller
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
| | - Karen A. Krogfelt
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
| | - Krystyna Kazmierczak
- Jesse Brown Veterans Administration Medical Center, Chicago, Illinois, USA
- Department of Microbiology, University of Illinois—Chicago, Chicago, Illinois, USA
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Linda J. Kenney
- Jesse Brown Veterans Administration Medical Center, Chicago, Illinois, USA
- Department of Microbiology, University of Illinois—Chicago, Chicago, Illinois, USA
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore
| | - Tyrrell Conway
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Paul S. Cohen
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island, USA
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Braun V, Patzer SI. Intercellular communication by related bacterial protein toxins: colicins, contact-dependent inhibitors, and proteins exported by the type VI secretion system. FEMS Microbiol Lett 2013; 345:13-21. [PMID: 23701660 DOI: 10.1111/1574-6968.12180] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 12/15/2022] Open
Abstract
Bacteria are in constant conflict with competing bacterial and eukaryotic cells. To cope with the various challenges, bacteria developed distinct strategies, such as toxins that inhibit the growth or kill rivals of the same ecological niche. In recent years, two toxin systems have been discovered - the type VI secretion system and the contact-dependent growth inhibition (CDI) system. These systems have structural and functional similarities and share features with the long-known gram-negative bacteriocins, such as small immunity proteins that bind to and inactivate the toxins, and target sites on DNA, tRNA, rRNA, murein (peptidoglycan), or the cytoplasmic membrane. Colicins, CdiA proteins, and certain type VI toxins have a modular design with the transport functions localized in the N-terminal region and the activity functions localized in the C-terminal region. Despite these common properties, the sequences of toxins and immunity proteins of colicins, CDI systems, and type VI systems show little similarity.
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Affiliation(s)
- Volkmar Braun
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Tübingen, Germany.
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Johnson CL, Ridley H, Pengelly RJ, Salleh MZ, Lakey JH. The unstructured domain of colicin N kills Escherichia coli. Mol Microbiol 2013; 89:84-95. [PMID: 23672584 PMCID: PMC3739937 DOI: 10.1111/mmi.12260] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2013] [Indexed: 11/28/2022]
Abstract
Bacteria often produce toxins which kill competing bacteria. Colicins, produced by and toxic to Escherichia coli bacteria are three-domain proteins so efficient that one molecule can kill a cell. The C-terminal domain carries the lethal activity and the central domain is required for surface receptor binding. The N-terminal domain, required for translocation across the outer membrane, is always intrinsically unstructured. It has always been assumed therefore that the C-terminal cytotoxic domain is required for the bactericidal activity. Here we report the unexpected finding that in isolation, the 90-residue unstructured N-terminal domain of colicin N is cytotoxic. Furthermore it causes ion leakage from cells but, unlike known antimicrobial peptides (AMPs) with this property, shows no membrane binding behaviour. Finally, its activity remains strictly dependent upon the same receptor proteins (OmpF and TolA) used by full-length colicin N. This mechanism of rapid membrane disruption, via receptor mediated binding of a soluble peptide, may reveal a new target for the development of highly specific antibacterials.
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Affiliation(s)
- Christopher L Johnson
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle- upon-Tyne, NE2 4HH, UK
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Fitness, stress resistance, and extraintestinal virulence in Escherichia coli. Infect Immun 2013; 81:2733-42. [PMID: 23690401 DOI: 10.1128/iai.01329-12] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The extraintestinal virulence of Escherichia coli is dependent on numerous virulence genes. However, there is growing evidence for a role of the metabolic properties and stress responses of strains in pathogenesis. We assessed the respective roles of these factors in strain virulence by developing phenotypic assays for measuring in vitro individual and competitive fitness and the general stress response, which we applied to 82 commensal and extraintestinal pathogenic E. coli strains previously tested in a mouse model of sepsis. Individual fitness properties, in terms of maximum growth rates in various media (Luria-Bertani broth with and without iron chelator, minimal medium supplemented with gluconate, and human urine) and competitive fitness properties, estimated as the mean relative growth rate per generation in mixed cultures with a reference fluorescent E. coli strain, were highly diverse between strains. The activity of the main general stress response regulator, RpoS, as determined by iodine staining of the colonies, H2O2 resistance, and rpoS sequencing, was also highly variable. No correlation between strain fitness and stress resistance and virulence in the mouse model was found, except that the maximum growth rate in urine was higher for virulent strains. Multivariate analysis showed that the number of virulence factors was the only independent factor explaining the virulence in mice. At the species level, growth capacity and stress resistance are heterogeneous properties that do not contribute significantly to the intrinsic virulence of the strains.
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46
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Abstract
The field of ecology has long recognized two types of competition: exploitative competition, which occurs indirectly through resource consumption, and interference competition, whereby one individual directly harms another. Here, we argue that these two forms of competition have played a dominant role in the evolution of bacterial regulatory networks. In particular, we argue that several of the major bacterial stress responses detect ecological competition by sensing nutrient limitation (exploitative competition) or direct cell damage (interference competition). We call this competition sensing: a physiological response that detects harm caused by other cells and that evolved, at least in part, for that purpose. A key prediction of our hypothesis is that bacteria will counter-attack when they sense ecological competition but not when they sense abiotic stress. In support of this hypothesis, we show that bacteriocins and antibiotics are frequently upregulated by stress responses to nutrient limitation and cell damage but very rarely upregulated by stress responses to heat or osmotic stress, which typically are not competition related. We argue that stress responses, in combination with the various mechanisms that sense secretions, enable bacteria to infer the presence of ecological competition and navigate the 'microbe-kill-microbe' world in which they live.
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Kamenšek S, Žgur-Bertok D. Global transcriptional responses to the bacteriocin colicin M in Escherichia coli. BMC Microbiol 2013; 13:42. [PMID: 23421615 PMCID: PMC3599342 DOI: 10.1186/1471-2180-13-42] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 02/18/2013] [Indexed: 01/17/2023] Open
Abstract
Background Bacteriocins are protein antimicrobial agents that are produced by all prokaryotic lineages. Escherichia coli strains frequently produce the bacteriocins known as colicins. One of the most prevalent colicins, colicin M, can kill susceptible cells by hydrolyzing the peptidoglycan lipid II intermediate, which arrests peptidoglycan polymerization steps and provokes cell lysis. Due to the alarming rise in antibiotic resistance and the lack of novel antimicrobial agents, colicin M has recently received renewed attention as a promising antimicrobial candidate. Here the effects of subinhibitory concentrations of colicin M on whole genome transcription in E. coli were investigated, to gain insight into its ecological role and for purposes related to antimicrobial therapy. Results Transcriptome analysis revealed that exposure to subinhibitory concentrations of colicin M altered expression of genes involved in envelope, osmotic and other stresses, including genes of the CreBC two-component system, exopolysaccharide production and cell motility. Nonetheless, there was no induction of biofilm formation or genes involved in mutagenesis. Conclusion At subinhibitory concentrations colicin M induces an adaptive response primarily to protect the bacterial cells against envelope stress provoked by peptidoglycan damage. Among the first induced were genes of the CreBC two-component system known to promote increased resistance against colicins M and E2, providing novel insight into the ecology of colicin M production in natural environments. While an adaptive response was induced nevertheless, colicin M application did not increase biofilm formation, nor induce SOS genes, adverse effects that can be provoked by a number of traditional antibiotics, providing support for colicin M as a promising antimicrobial agent.
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Affiliation(s)
- Simona Kamenšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000, Ljubljana, Slovenia
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Braun V, Hantke K. The Tricky Ways Bacteria Cope with Iron Limitation. IRON UPTAKE IN BACTERIA WITH EMPHASIS ON E. COLI AND PSEUDOMONAS 2013. [DOI: 10.1007/978-94-007-6088-2_2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Affiliation(s)
- Karen S. Jakes
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461;
| | - William A. Cramer
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907;
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50
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Colicin A binds to a novel binding site of TolA in the Escherichia coli periplasm. Biochem Soc Trans 2012; 40:1469-74. [DOI: 10.1042/bst20120239] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Colicins are protein antibiotics produced by Escherichia coli to kill closely related non-identical competing species. They have taken advantage of the promiscuity of several proteins in the cell envelope for entry into the bacterial cell. The Tol–Pal system comprises one such ensemble of periplasmic and membrane-associated interacting proteins that links the IM (inner membrane) and OM (outer membrane) and provides the cell with a structural scaffold for cell division and energy transduction. Central to the Tol–Pal system is the TolA hub protein which forms protein–protein interactions with all other members and also with extrinsic proteins such as colicins A, E1, E2–E9 and N, and the coat proteins of the Ff family of filamentous bacteriophages. In the present paper, we review the role of TolA in the translocation of colicin A through the recently determined crystal structure of the complex of TolA with a translocation domain peptide of ColA (TA53–107), we demonstrate that TA53–107 binds to TolA at a novel binding site and compare the interactions of TolA with other colicins that use the Tol–Pal system for cell entry substantiating further the role of TolA as a periplasmic hub protein.
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