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Ai Y, Li X, Wu X, Montalbán-López M, Zheng Z, Mu D. Secreting recombinant barnase by Lactococcus lactis and its application in reducing RNA from forages. Enzyme Microb Technol 2023; 164:110191. [PMID: 36608408 DOI: 10.1016/j.enzmictec.2022.110191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/18/2022] [Accepted: 12/29/2022] [Indexed: 01/02/2023]
Abstract
Barnase is a ribonuclease used for plasmid purification, targeted gene therapy and studies of protein interactions. To make the use of barnase easier, the barnase gene from Bacillus amyloliquefaciens BH072 was cloned into Lactococcus lactis under the control of the PP5 or PnisA promoters. Four recombinant expression vectors were constructed with one or two signal peptides to control the enzyme secretion. 310 mg/L barnase was obtained in the presence of its inhibitor barstar after 36 h induction. The properties of barnase were investigated, showing that the optimal reaction temperature and pH were 50 °C and 5.0, respectively, and the highest enzyme activity reached 16.5 kU/mL. Barnase stored at 40 °C for 72 h retained 90 % of its initial activity, and maintained more than 80 % of its initial activity after 72 h of storage at pH 5.0-9.0. Furthermore, the optimal conditions for enzymatic reduction of nucleic acids in single-cell proteins (SCP) forages was investigated. 1 % salt solution with an SCP-enzyme ratio of 1000:1, pH 5.0 and incubated at 50 °C for 1 h, allowed 82 % RNA content reduction. Finally, homology modeling of barnase demonstrates its three-dimensional structure, and substrate simulation docking predicts key active residues as well as bonding patterns.
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Affiliation(s)
- Yaqian Ai
- Anhui Fermented Food Engineering Research Center, School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Xingjiang Li
- Anhui Fermented Food Engineering Research Center, School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Xuefeng Wu
- Anhui Fermented Food Engineering Research Center, School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Manuel Montalbán-López
- Department of Microbiology, Faculty of Sciences, University of Granada, Granada 18071, Spain
| | - Zhi Zheng
- Key Laboratory for Agricultural Products Processing of Anhui Province, School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Dongdong Mu
- Anhui Fermented Food Engineering Research Center, School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China; Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China.
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Cebrián R, Martínez-García M, Fernández M, García F, Martínez-Bueno M, Valdivia E, Kuipers OP, Montalbán-López M, Maqueda M. Advances in the preclinical characterization of the antimicrobial peptide AS-48. Front Microbiol 2023; 14:1110360. [PMID: 36819031 PMCID: PMC9936517 DOI: 10.3389/fmicb.2023.1110360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/11/2023] [Indexed: 02/05/2023] Open
Abstract
Antimicrobial resistance is a natural and inevitable phenomenon that constitutes a severe threat to global public health and economy. Innovative products, active against new targets and with no cross- or co-resistance with existing antibiotic classes, novel mechanisms of action, or multiple therapeutic targets are urgently required. For these reasons, antimicrobial peptides such as bacteriocins constitute a promising class of new antimicrobial drugs under investigation for clinical development. Here, we review the potential therapeutic use of AS-48, a head-to-tail cyclized cationic bacteriocin produced by Enterococcus faecalis. In the last few years, its potential against a wide range of human pathogens, including relevant bacterial pathogens and trypanosomatids, has been reported using in vitro tests and the mechanism of action has been investigated. AS-48 can create pores in the membrane of bacterial cells without the mediation of any specific receptor. However, this mechanism of action is different when susceptible parasites are studied and involves intracellular targets. Due to these novel mechanisms of action, AS-48 remains active against the antibiotic resistant strains tested. Remarkably, the effect of AS-48 against eukaryotic cell lines and in several animal models show little effect at the doses needed to inhibit susceptible species. The characteristics of this molecule such as low toxicity, microbicide activity, blood stability and activity, high stability at a wide range of temperatures or pH, resistance to proteases, and the receptor-independent effect make AS-48 unique to fight a broad range of microbial infections, including bacteria and some important parasites.
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Affiliation(s)
- Rubén Cebrián
- Department of Clinical Microbiology, Instituto de Investigación Biosanitaria Ibs.GRANADA, University Hospital San Cecilio, Granada, Spain,*Correspondence: Rubén Cebrián, ✉
| | | | | | - Federico García
- Department of Clinical Microbiology, Instituto de Investigación Biosanitaria Ibs.GRANADA, University Hospital San Cecilio, Granada, Spain,Biomedicinal Research Network Center, Infectious Diseases (CIBERINFEC), Madrid, Spain
| | | | - Eva Valdivia
- Department of Microbiology, University of Granada, Granada, Spain
| | - Oscar P. Kuipers
- Department of Molecular Genetics, University of Groningen, Groningen, Netherlands
| | - Manuel Montalbán-López
- Department of Microbiology, University of Granada, Granada, Spain,Manuel Montalbán-López, ✉
| | - Mercedes Maqueda
- Department of Microbiology, University of Granada, Granada, Spain
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3
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Li Q, Cebrián R, Montalbán-López M, Ren H, Wu W, Kuipers OP. Outer-membrane-acting peptides and lipid II-targeting antibiotics cooperatively kill Gram-negative pathogens. Commun Biol 2021; 4:31. [PMID: 33398076 PMCID: PMC7782785 DOI: 10.1038/s42003-020-01511-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 11/11/2020] [Indexed: 02/08/2023] Open
Abstract
The development and dissemination of antibiotic-resistant bacterial pathogens is a growing global threat to public health. Novel compounds and/or therapeutic strategies are required to face the challenge posed, in particular, by Gram-negative bacteria. Here we assess the combined effect of potent cell-wall synthesis inhibitors with either natural or synthetic peptides that can act on the outer-membrane. Thus, several linear peptides, either alone or combined with vancomycin or nisin, were tested against selected Gram-negative pathogens, and the best one was improved by further engineering. Finally, peptide D-11 and vancomycin displayed a potent antimicrobial activity at low μM concentrations against a panel of relevant Gram-negative pathogens. This combination was highly active in biological fluids like blood, but was non-hemolytic and non-toxic against cell lines. We conclude that vancomycin and D-11 are safe at >50-fold their MICs. Based on the results obtained, and as a proof of concept for the newly observed synergy, a Pseudomonas aeruginosa mouse infection model experiment was also performed, showing a 4 log10 reduction of the pathogen after treatment with the combination. This approach offers a potent alternative strategy to fight (drug-resistant) Gram-negative pathogens in humans and mammals.
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Affiliation(s)
- Qian Li
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands ,grid.34418.3a0000 0001 0727 9022Present Address: State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, China
| | - Rubén Cebrián
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Manuel Montalbán-López
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands ,grid.4489.10000000121678994Present Address: Department of Microbiology, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071 Granada, Spain
| | - Huan Ren
- grid.216938.70000 0000 9878 7032State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, 30071 Tianjin, China
| | - Weihui Wu
- grid.216938.70000 0000 9878 7032State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, 30071 Tianjin, China
| | - Oscar P. Kuipers
- grid.4830.f0000 0004 0407 1981Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 7, 9747AG Groningen, The Netherlands
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Montalbán-López M, Scott TA, Ramesh S, Rahman IR, van Heel AJ, Viel JH, Bandarian V, Dittmann E, Genilloud O, Goto Y, Grande Burgos MJ, Hill C, Kim S, Koehnke J, Latham JA, Link AJ, Martínez B, Nair SK, Nicolet Y, Rebuffat S, Sahl HG, Sareen D, Schmidt EW, Schmitt L, Severinov K, Süssmuth RD, Truman AW, Wang H, Weng JK, van Wezel GP, Zhang Q, Zhong J, Piel J, Mitchell DA, Kuipers OP, van der Donk WA. New developments in RiPP discovery, enzymology and engineering. Nat Prod Rep 2021; 38:130-239. [PMID: 32935693 PMCID: PMC7864896 DOI: 10.1039/d0np00027b] [Citation(s) in RCA: 358] [Impact Index Per Article: 119.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Covering: up to June 2020Ribosomally-synthesized and post-translationally modified peptides (RiPPs) are a large group of natural products. A community-driven review in 2013 described the emerging commonalities in the biosynthesis of RiPPs and the opportunities they offered for bioengineering and genome mining. Since then, the field has seen tremendous advances in understanding of the mechanisms by which nature assembles these compounds, in engineering their biosynthetic machinery for a wide range of applications, and in the discovery of entirely new RiPP families using bioinformatic tools developed specifically for this compound class. The First International Conference on RiPPs was held in 2019, and the meeting participants assembled the current review describing new developments since 2013. The review discusses the new classes of RiPPs that have been discovered, the advances in our understanding of the installation of both primary and secondary post-translational modifications, and the mechanisms by which the enzymes recognize the leader peptides in their substrates. In addition, genome mining tools used for RiPP discovery are discussed as well as various strategies for RiPP engineering. An outlook section presents directions for future research.
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Montalbán-López M, Cebrián R, Galera R, Mingorance L, Martín-Platero AM, Valdivia E, Martínez-Bueno M, Maqueda M. Synergy of the Bacteriocin AS-48 and Antibiotics against Uropathogenic Enterococci. Antibiotics (Basel) 2020; 9:antibiotics9090567. [PMID: 32887311 PMCID: PMC7558097 DOI: 10.3390/antibiotics9090567] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 08/28/2020] [Accepted: 08/31/2020] [Indexed: 01/01/2023] Open
Abstract
The genus Enterococcus comprises a ubiquitous group of Gram-positive bacteria that can cause diverse health care-associated infections. Their genome plasticity enables easy acquisition of virulence factors as well as antibiotic resistances. Urinary tract infections (UTIs) and catheter-associated UTIs are common diseases caused by enterococci. In this study, Enterococcus strains isolated from UTIs were characterized, showing that the majority were E. faecalis and contained several virulence factors associated to a better colonization of the urinary tract. Their susceptibility against the bacteriocin AS-48 and several antibiotics was tested. AS-48 is a potent circular bacteriocin that causes bacterial death by pore formation in the cell membrane. The interest of this bacteriocin is based on the potent inhibitory activity, the high stability against environmental conditions, and the low toxicity. AS-48 was active at concentrations below 10 mg/L even against antibiotic-resistant strains, whereas these strains showed resistance to, at least, seven of the 20 antibiotics tested. Moreover, the effect of AS-48 combined with antibiotics commonly used to treat UTIs was largely synergistic (with up to 100-fold MIC reduction) and only occasionally additive. These data suggest AS-48 as a potential novel drug to deal with or prevent enterococcal infections.
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Ma T, Lu J, Zhu J, Li X, Gu H, Montalbán-López M, Wu X, Luo S, Zhao Y, Jiang S, Zheng Z, Mu D. The Secretion of Streptomyces monbaraensis Transglutaminase From Lactococcus lactis and Immobilization on Porous Magnetic Nanoparticles. Front Microbiol 2019; 10:1675. [PMID: 31447792 PMCID: PMC6691175 DOI: 10.3389/fmicb.2019.01675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/08/2019] [Indexed: 01/27/2023] Open
Abstract
Microbial transglutaminase (MTG) from Streptomyces mobaraensis is an important enzyme widely applied in food processing for the improvement of protein properties by catalyzing the cross-linking of proteins. In this work we aimed at improving the production and enabling an easy and efficient purification process from culture supernatants. Thus, recombinant vectors, with either a constitutive promoter (Pp5) or an inducible promoter (PnisA), controlling the expression of the MTG gene fused to the signal peptide of Usp45 (SPusp45) were constructed and then expressed in Lactococcus lactis. After purification, 43.5 ± 0.4 mg/L mature MTG-6His was obtained. It displayed 27.6 ± 0.5 U/mg enzymatic activity cross-linking soy protein isolate effectively. The purified mature MTG was immobilized with magnetic porous Fe3O4 nanoparticles, which improved its activity up to 29.1 ± 0.4 U/mg. The immobilized MTG maintained 67.2% of the initial activity after being recycled for 10 times. The high production and secretion of functional S. mobaraensis MTG from L. lactis and the magnetic immobilized MTG-6His onto Fe3O4 nanoparticles reported in this study would have potential industrial applications.
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Affiliation(s)
- Tiange Ma
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Jiaojiao Lu
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Jing Zhu
- State Key Laboratory of Tea Plant Biology and Utilization, School of Science, Anhui Agricultural University, Hefei, China
| | - Xingjiang Li
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Hongwei Gu
- College of Chemistry, Soochow University, Suzhou, China
| | | | - Xuefeng Wu
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Shuizhong Luo
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Yanyan Zhao
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Shaotong Jiang
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Zhi Zheng
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China
| | - Dongdong Mu
- School of Food and Biological Engineering, Key Laboratory for Agricultural Products Processing of Anhui Province, Hefei University of Technology, Hefei, China.,Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
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7
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Cebrián R, Rodríguez-Cabezas ME, Martín-Escolano R, Rubiño S, Garrido-Barros M, Montalbán-López M, Rosales MJ, Sánchez-Moreno M, Valdivia E, Martínez-Bueno M, Marín C, Gálvez J, Maqueda M. Preclinical studies of toxicity and safety of the AS-48 bacteriocin. J Adv Res 2019; 20:129-139. [PMID: 31360546 PMCID: PMC6637140 DOI: 10.1016/j.jare.2019.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 06/25/2019] [Accepted: 06/29/2019] [Indexed: 12/15/2022] Open
Abstract
The in vitro antimicrobial potency of the bacteriocin AS-48 is well documented, but its clinical application requires investigation, as its toxicity could be different in in vitro (haemolytic and antibacterial activity in blood and cytotoxicity towards normal human cell lines) and in vivo (e.g. mice and zebrafish embryos) models. Overall, the results obtained are promising. They reveal the negligible propensity of AS-48 to cause cell death or impede cell growth at therapeutic concentrations (up to 27 μM) and support the suitability of this peptide as a potential therapeutic agent against several microbial infections, due to its selectivity and potency at low concentrations (in the range of 0.3-8.9 μM). In addition, AS-48 exhibits low haemolytic activity in whole blood and does not induce nitrite accumulation in non-stimulated RAW macrophages, indicating a lack of pro-inflammatory effects. The unexpected heightened sensitivity of zebrafish embryos to AS-48 could be due to the low differentiation state of these cells. The low cytotoxicity of AS-48, the absence of lymphocyte proliferation in vivo after skin sensitization in mice, and the lack of toxicity in a murine model support the consideration of the broad spectrum antimicrobial peptide AS-48 as a promising therapeutic agent for the control of a vast array of microbial infections, in particular, those involved in skin and soft tissue diseases.
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Affiliation(s)
- Rubén Cebrián
- Department of Molecular Genetics, Faculty of Science and Engineering, Nijenborgh 7, 9747 AG, University of Groningen, Groningen, the Netherlands
| | - M Elena Rodríguez-Cabezas
- CIBER-EHD, Department of Pharmacology. Centre for Biomedical Research (CIBM), Avda del Conocimiento s/n, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria de Granada (Ibs.GRANADA), Granada, Spain
| | - Rubén Martín-Escolano
- Department of Parasitology, Instituto de Investigación Biosanitaria (ibs.Granada), Hospitales Universitarios de Granada/University of Granada, Severo Ochoa s/n, E-18071 Granada, Spain
| | - Susana Rubiño
- Department of Microbiology, Faculty of Sciences, Avda Fuentenueva s/n, University of Granada, 18071 Granada, Spain
| | - María Garrido-Barros
- CIBER-EHD, Department of Pharmacology. Centre for Biomedical Research (CIBM), Avda del Conocimiento s/n, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria de Granada (Ibs.GRANADA), Granada, Spain
| | - Manuel Montalbán-López
- Department of Microbiology, Faculty of Sciences, Avda Fuentenueva s/n, University of Granada, 18071 Granada, Spain
| | - María José Rosales
- Department of Parasitology, Instituto de Investigación Biosanitaria (ibs.Granada), Hospitales Universitarios de Granada/University of Granada, Severo Ochoa s/n, E-18071 Granada, Spain
| | - Manuel Sánchez-Moreno
- Department of Parasitology, Instituto de Investigación Biosanitaria (ibs.Granada), Hospitales Universitarios de Granada/University of Granada, Severo Ochoa s/n, E-18071 Granada, Spain
| | - Eva Valdivia
- Department of Microbiology, Faculty of Sciences, Avda Fuentenueva s/n, University of Granada, 18071 Granada, Spain
| | - Manuel Martínez-Bueno
- Department of Microbiology, Faculty of Sciences, Avda Fuentenueva s/n, University of Granada, 18071 Granada, Spain
| | - Clotilde Marín
- Department of Parasitology, Instituto de Investigación Biosanitaria (ibs.Granada), Hospitales Universitarios de Granada/University of Granada, Severo Ochoa s/n, E-18071 Granada, Spain
| | - Julio Gálvez
- CIBER-EHD, Department of Pharmacology. Centre for Biomedical Research (CIBM), Avda del Conocimiento s/n, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria de Granada (Ibs.GRANADA), Granada, Spain
| | - Mercedes Maqueda
- Department of Microbiology, Faculty of Sciences, Avda Fuentenueva s/n, University of Granada, 18071 Granada, Spain
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8
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Schmitt S, Montalbán-López M, Peterhoff D, Deng J, Wagner R, Held M, Kuipers OP, Panke S. Analysis of modular bioengineered antimicrobial lanthipeptides at nanoliter scale. Nat Chem Biol 2019; 15:437-443. [PMID: 30936500 DOI: 10.1038/s41589-019-0250-5] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 02/20/2019] [Indexed: 01/22/2023]
Abstract
The rise of antibiotic resistance demands the acceleration of molecular diversification strategies to inspire new chemical entities for antibiotic medicines. We report here on the large-scale engineering of ribosomally synthesized and post-translationally modified antimicrobial peptides carrying the ring-forming amino acid lanthionine. New-to-nature variants featuring distinct properties were obtained by combinatorial shuffling of peptide modules derived from 12 natural antimicrobial lanthipeptides and processing by a promiscuous post-translational modification machinery. For experimental characterization, we developed the nanoFleming, a miniaturized and parallelized high-throughput inhibition assay. On the basis of a hit set of >100 molecules, we identified variants with improved activity against pathogenic bacteria and shifted activity profiles, and extrapolated design guidelines that will simplify the identification of peptide-based anti-infectives in the future.
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Affiliation(s)
- Steven Schmitt
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | | | - David Peterhoff
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Jingjing Deng
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany.,Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
| | - Martin Held
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Oscar P Kuipers
- Department of Molecular Genetics, University of Groningen, Groningen, The Netherlands.
| | - Sven Panke
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland.
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9
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Perales-Adán J, Rubiño S, Martínez-Bueno M, Valdivia E, Montalbán-López M, Cebrián R, Maqueda M. LAB Bacteriocins Controlling the Food Isolated (Drug-Resistant) Staphylococci. Front Microbiol 2018; 9:1143. [PMID: 29946300 PMCID: PMC6005826 DOI: 10.3389/fmicb.2018.01143] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/14/2018] [Indexed: 12/20/2022] Open
Abstract
Staphylococci are a group of microorganisms that can be often found in processed food and they might pose a risk for human health. In this study we have determined the content of staphylococci in 7 different fresh goat-milk cheeses. These bacteria were present in all of them, ranging from 103 to 106 CFU/g based on growth on selective media. Thus, a set of 97 colonies was randomly picked for phenotypic and genotypic identification. They could be clustered by RAPD-PCR in 10 genotypes, which were assigned by 16S rDNA sequencing to four Staphylococcus species: Staphylococcus aureus, Staphylococcus chromogenes, S. simulans, and S. xylosus. Representative strains of these species (n = 25) were tested for antibiotic sensitivity, and 11 of them were resistant to at least one of the antibiotics tested, including erythromycin, amoxicillin-clavulanic acid and oxacillin. We also tested two bacteriocins produced by lactic acid bacteria (LAB), namely the circular bacteriocin AS-48 and the lantibiotic nisin. These peptides have different mechanism of action at the membrane level. Nevertheless, both were able to inhibit staphylococci growth at low concentrations ranging between 0.16-0.73 μM for AS-48 and 0.02-0.23 μM for nisin, including the strains that displayed antibiotic resistance. The combined effect of these bacteriocins were tested and the fractional inhibitory concentration index (FICI) was calculated. Remarkably, upon combination, they were active at the low micromolar range with a significant reduction of the minimal inhibitory concentration. Our data confirms synergistic effect, either total or partial, between AS-48 and nisin for the control of staphylococci and including antibiotic resistant strains. Collectively, these results indicate that the combined use of AS-48 and nisin could help controlling (pathogenic) staphylococci in food processing and preventing antibiotic-resistant strains reaching the consumer in the final products.
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10
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Montalbán-López M, Deng J, van Heel AJ, Kuipers OP. Specificity and Application of the Lantibiotic Protease NisP. Front Microbiol 2018; 9:160. [PMID: 29479343 PMCID: PMC5812297 DOI: 10.3389/fmicb.2018.00160] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/24/2018] [Indexed: 01/03/2023] Open
Abstract
Lantibiotics are ribosomally produced and posttranslationally modified peptides containing several lanthionine residues. They exhibit substantial antimicrobial activity against Gram-positive bacteria, including relevant pathogens. The production of the model lantibiotic nisin minimally requires the expression of the modification and export machinery. The last step during nisin maturation is the cleavage of the leader peptide. This liberates the active compound and is catalyzed by the cell wall-anchored protease NisP. Here, we report the production and purification of a soluble variant of NisP. This has enabled us to study its specificity and test its suitability for biotechnological applications. The ability of soluble NisP to cleave leaders from various substrates was tested with two sets of nisin variants. The first set was designed to investigate the influence of amino acid variations in the leader peptide or variations around the cleavage site. The second set was designed to study the influence of the lanthionine ring topology on the proteolytic efficiency. We show that the substrate promiscuity is higher than has previously been suggested. Our results demonstrate the importance of the arginine residue at the end of the leader peptide and the importance of lanthionine rings in the substrate for specific cleavage. Collectively, these data indicate that NisP is a suitable protease for the activation of diverse heterologously expressed lantibiotics, which is required to release active antimicrobial compounds.
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Affiliation(s)
| | - Jingjing Deng
- Department Molecular Genetics, University of Groningen, Groningen, Netherlands
| | - Auke J van Heel
- Department Molecular Genetics, University of Groningen, Groningen, Netherlands
| | - Oscar P Kuipers
- Department Molecular Genetics, University of Groningen, Groningen, Netherlands
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11
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Bartholomae M, Buivydas A, Viel JH, Montalbán-López M, Kuipers OP. Major gene-regulatory mechanisms operating in ribosomally synthesized and post-translationally modified peptide (RiPP) biosynthesis. Mol Microbiol 2017; 106:186-206. [DOI: 10.1111/mmi.13764] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 02/06/2023]
Affiliation(s)
- Maike Bartholomae
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
| | - Andrius Buivydas
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
| | - Jakob H. Viel
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
| | - Manuel Montalbán-López
- Department of Microbiology; University of Granada, C. Fuentenueva s/n; 18071 Granada Spain
| | - Oscar P. Kuipers
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
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Montalbán-López M, van Heel AJ, Kuipers OP. Employing the promiscuity of lantibiotic biosynthetic machineries to produce novel antimicrobials. FEMS Microbiol Rev 2016; 41:5-18. [PMID: 27591436 DOI: 10.1093/femsre/fuw034] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/07/2016] [Accepted: 07/28/2016] [Indexed: 12/30/2022] Open
Abstract
As the number of new antibiotics that reach the market is decreasing and the demand for them is rising, alternative sources of novel antimicrobials are needed. Lantibiotics are potent peptide antimicrobials that are ribosomally synthesized and stabilized by post-translationally introduced lanthionine rings. Their ribosomal synthesis and enzymatic modifications provide excellent opportunities to design and engineer a large variety of novel antimicrobial compounds. The research conducted in this area demonstrates that the modularity present in both the peptidic rings as well as in the combination of promiscuous modification enzymes can be exploited to further increase the diversity of lantibiotics. Various approaches, where the modifying enzymes and corresponding leader peptides are decoupled from their natural core peptide and integrated in designed plug-and-play production systems, enable the production of modified peptides that are either derived from vast genomic data or designed using functional parts from a wide diversity of core peptides. These approaches constitute a powerful discovery platform to develop novel antimicrobials with high therapeutic potential.
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Affiliation(s)
- Manuel Montalbán-López
- Department of Molecular Genetics, University of Groningen, Nijenborgh 7, 9747AG Groningen, the Netherlands
| | - Auke J van Heel
- Department of Molecular Genetics, University of Groningen, Nijenborgh 7, 9747AG Groningen, the Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, University of Groningen, Nijenborgh 7, 9747AG Groningen, the Netherlands
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Abstract
In this issue of Cell Chemical Biology, Ortega et al. (2016) determine the structure of another lantibiotic dehydratase with a tRNA(Glu)-dependent mechanism of modification. Moreover, they identify a common recognition motif involved in leader peptide binding in a number of different peptide-modification enzymes. These findings open up new mining possibilities and allow novel approaches in peptide engineering.
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Affiliation(s)
- Manuel Montalbán-López
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, the Netherlands
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, Nijenborgh 7, 9747 AG Groningen, the Netherlands.
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Valverde-Tercedor C, Montalbán-López M, Perez-Gonzalez T, Sanchez-Quesada MS, Prozorov T, Pineda-Molina E, Fernandez-Vivas MA, Rodriguez-Navarro AB, Trubitsyn D, Bazylinski DA, Jimenez-Lopez C. Size control of in vitro synthesized magnetite crystals by the MamC protein of Magnetococcus marinus strain MC-1. Appl Microbiol Biotechnol 2015; 99:5109-21. [PMID: 25874532 DOI: 10.1007/s00253-014-6326-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 12/09/2014] [Accepted: 12/14/2014] [Indexed: 11/27/2022]
Abstract
Magnetotactic bacteria are a diverse group of prokaryotes that share the unique ability of biomineralizing magnetosomes, which are intracellular, membrane-bounded crystals of either magnetite (Fe3O4) or greigite (Fe3S4). Magnetosome biomineralization is mediated by a number of specific proteins, many of which are localized in the magnetosome membrane, and thus is under strict genetic control. Several studies have partially elucidated the effects of a number of these magnetosome-associated proteins in the control of the size of magnetosome magnetite crystals. However, the effect of MamC, one of the most abundant proteins in the magnetosome membrane, remains unclear. In this present study, magnetite nanoparticles were synthesized inorganically in free-drift experiments at 25 °C in the presence of different concentrations of the iron-binding recombinant proteins MamC and MamCnts (MamC without its first transmembrane segment) from the marine, magnetotactic bacterium Magnetococcus marinus strain MC-1 and three commercial proteins [α-lactalbumin (α-Lac), myoglobin (Myo), and lysozyme (Lyz)]. While no effect was observed on the size of magnetite crystals formed in the presence of the commercial proteins, biomimetic synthesis in the presence of MamC and MamCnts at concentrations of 10-60 μg/mL resulted in the production of larger and more well-developed magnetite crystals (~30-40 nm) compared to those of the control (~20-30 nm; magnetite crystals grown protein-free). Our results demonstrate that MamC plays an important role in the control of the size of magnetite crystals and could be utilized in biomimetic synthesis of magnetite nanocrystals.
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Affiliation(s)
- C Valverde-Tercedor
- Departamento de Microbiologia, Universidad de Granada, Campus de Fuentenueva s/n, 18071, Granada, Spain,
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Cebrián R, Rodríguez-Ruano S, Martínez-Bueno M, Valdivia E, Maqueda M, Montalbán-López M. Analysis of the promoters involved in enterocin AS-48 expression. PLoS One 2014; 9:e90603. [PMID: 24594763 PMCID: PMC3942455 DOI: 10.1371/journal.pone.0090603] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/31/2014] [Indexed: 11/17/2022] Open
Abstract
The enterocin AS-48 is the best characterized antibacterial circular protein in prokaryotes. It is a hydrophobic and cationic bacteriocin, which is ribosomally synthesized by enterococcal cells and post-translationally cyclized by a head-to-tail peptide bond. The production of and immunity towards AS-48 depend upon the coordinated expression of ten genes organized in two operons, as-48ABC (where genes encoding enzymes with processing, secretion, and immunity functions are adjacent to the structural as-48A gene) and as-48C1DD1EFGH. The current study describes the identification of the promoters involved in AS-48 expression. Seven putative promoters have been here amplified, and separately inserted into the promoter-probe vector pTLR1, to create transcriptional fusions with the mCherry gene used as a reporter. The activity of these promoter regions was assessed measuring the expression of the fluorescent mCherry protein using the constitutive pneumococcal promoter PX as a reference. Our results revealed that only three promoters PA, P2(2) and PD1 were recognized in Enterococcus faecalis, Lactococcus lactis and Escherichia coli, in the conditions tested. The maximal fluorescence was obtained with PX in all the strains, followed by the P2(2) promoter, which level of fluorescence was 2-fold compared to PA and 4-fold compared to PD1. Analysis of putative factors influencing the promoter activity in single and double transformants in E. faecalis JH2-2 demonstrated that, in general, a better expression was achieved in presence of pAM401-81. In addition, the P2(2) promoter could be regulated in a negative fashion by genes existing in the native pMB-2 plasmid other than those of the as-48 cluster, while the pH seems to affect differently the as-48 promoter expression.
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Affiliation(s)
- Rubén Cebrián
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Sonia Rodríguez-Ruano
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Manuel Martínez-Bueno
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Eva Valdivia
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Mercedes Maqueda
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Manuel Montalbán-López
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Granada, Spain
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van Heel AJ, Mu D, Montalbán-López M, Hendriks D, Kuipers OP. Designing and producing modified, new-to-nature peptides with antimicrobial activity by use of a combination of various lantibiotic modification enzymes. ACS Synth Biol 2013; 2:397-404. [PMID: 23654279 DOI: 10.1021/sb3001084] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lanthipeptides are peptides that contain several post-translationally modified amino acid residues and commonly show considerable antimicrobial activity. After translation, the amino acid residues of these peptides are modified by a distinct set of modification enzymes. This process results in peptides containing one or more lanthionine rings and dehydrated Ser and Thr residues. Previously, an in vivo lanthipeptide production system based on the modification machinery of the model lantibiotic nisin was reported. Here, we present the addition of the modification enzymes LtnJ and GdmD to this production system. With these enzymes we can now produce lanthipeptides that contain d-alanines or a C-terminal aminovinyl-cysteine. We show experimentally that the decarboxylase GdmD is responsible for the C-terminal decarboxylation. Our results demonstrate that different lanthipeptide modification enzymes can work together in an in vivo production system. This yields a plug-and-play system that can be used to select different sets of modification enzymes to work on diverse, specifically designed substrates.
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Affiliation(s)
- Auke J. van Heel
- University of Groningen, Linnaeusborg,
Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Dongdong Mu
- University of Groningen, Linnaeusborg,
Nijenborgh 7, 9747AG Groningen, The Netherlands
| | | | - Djoke Hendriks
- University of Groningen, Linnaeusborg,
Nijenborgh 7, 9747AG Groningen, The Netherlands
| | - Oscar P. Kuipers
- University of Groningen, Linnaeusborg,
Nijenborgh 7, 9747AG Groningen, The Netherlands
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van Heel AJ, de Jong A, Montalbán-López M, Kok J, Kuipers OP. BAGEL3: Automated identification of genes encoding bacteriocins and (non-)bactericidal posttranslationally modified peptides. Nucleic Acids Res 2013; 41:W448-53. [PMID: 23677608 PMCID: PMC3692055 DOI: 10.1093/nar/gkt391] [Citation(s) in RCA: 345] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Identifying genes encoding bacteriocins and ribosomally synthesized and posttranslationally modified peptides (RiPPs) can be a challenging task. Especially those peptides that do not have strong homology to previously identified peptides can easily be overlooked. Extensive use of BAGEL2 and user feedback has led us to develop BAGEL3. BAGEL3 features genome mining of prokaryotes, which is largely independent of open reading frame (ORF) predictions and has been extended to cover more (novel) classes of posttranslationally modified peptides. BAGEL3 uses an identification approach that combines direct mining for the gene and indirect mining via context genes. Especially for heavily modified peptides like lanthipeptides, sactipeptides, glycocins and others, this genetic context harbors valuable information that is used for mining purposes. The bacteriocin and context protein databases have been updated and it is now easy for users to submit novel bacteriocins or RiPPs. The output has been simplified to allow user-friendly analysis of the results, in particular for large (meta-genomic) datasets. The genetic context of identified candidate genes is fully annotated. As input, BAGEL3 uses FASTA DNA sequences or folders containing multiple FASTA formatted files. BAGEL3 is freely accessible at http://bagel.molgenrug.nl.
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Affiliation(s)
- Auke J van Heel
- Molecular Genetics, University of Groningen, Linnaeusborgh, Nijenborgh 7, 9747AG Groningen
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Montalbán-López M, Sánchez-Hidalgo M, Cebrián R, Maqueda M. Discovering the bacterial circular proteins: bacteriocins, cyanobactins, and pilins. J Biol Chem 2012; 287:27007-13. [PMID: 22700986 DOI: 10.1074/jbc.r112.354688] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Over recent years, several examples of natural ribosomally synthesized circular proteins and peptides from diverse organisms have been described. They are a group of proteins for which the precursors must be post-translationally modified to join the N and C termini with a peptide bond. This feature appears to confer a range of potential advantages because these proteins show increased resistance to proteases and higher thermodynamic stability, both of which improve their biological activity. They are produced by prokaryotic and eukaryotic organisms and show diverse biological activities, related mostly to a self-defense or competition mechanism of the producer organisms, with the only exception being the circular pilins. This minireview highlights ribosomally synthesized circular proteins produced by members of the domain Bacteria: circular bacteriocins, cyanobactins, and circular pilins. We pay special attention to the genetic organization of the biosynthetic machinery of these molecules, the role of circularization, and the differences in the possible circularization mechanisms.
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Affiliation(s)
- Manuel Montalbán-López
- Department of Molecular Genetics, University of Groningen, 9747 AG Groningen, The Netherlands
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Montalbán-López M, Zhou L, Buivydas A, van Heel AJ, Kuipers OP. Increasing the success rate of lantibiotic drug discovery by Synthetic Biology. Expert Opin Drug Discov 2012; 7:695-709. [PMID: 22680308 DOI: 10.1517/17460441.2012.693476] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Lantibiotics are post-translationally modified antimicrobial peptides produced by bacteria from diverse environments that exhibit an activity against pathogenic bacteria comparable to that of medically used antibiotics. The actual need for new antimicrobials in therapeutics has placed them in the pipeline of antibiotic research, due not only to their high antimicrobial activity but also to the fact that they are directed to novel targets. AREAS COVERED This review covers the different approaches traditionally used in bacteriocin discovery, based on the isolation of bacteria from different habitats and determining their inhibitory spectrum against a set of relevant strains. It also elaborates on more recent approaches covering organic synthesis and semi-synthesis of lantibiotics, genomic and proteomic approaches and the application of Synthetic Biology to the field of antimicrobial drug discovery. EXPERT OPINION Lantibiotics show a great potential in fulfilling the requirements for new antimicrobials. Culture-dependent techniques are still applied to lantibiotic discovery producing successful results that can be furthered by employing high-throughput screening techniques and peptidogenomics. The necessity of culturing bacteria and growing them in specific conditions for lantibiotic expression, can hamper the discovery rate, especially in exotic or unculturable bacteria. Thus, a combination of genome mining procedures, to detect novel lantibiotic-related sequences, with heterologous production systems and high-throughput screening, offers a promising strategy. Furthermore, the characterization of the mechanism of action of many lantibiotics, and the development of "plug and play" peptide biosynthesis systems, offers the possibility of initiating the rational design of non-natural lantibiotics based on structure-activity relationships.
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Affiliation(s)
- Manuel Montalbán-López
- University of Groningen, Molecular Genetics Group, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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Montalbán-López M, Martínez-Bueno M, Valdivia E, Maqueda M. Expression of linear permutated variants from circular enterocin AS-48. Biochimie 2010; 93:549-55. [PMID: 21130135 DOI: 10.1016/j.biochi.2010.11.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 11/24/2010] [Indexed: 10/18/2022]
Abstract
To confirm whether the head-to-tail circularization could be involved in the stability and activity of the circular bacteriocin AS-48, two permutated linear structural as-48A genes have been constructed by circular permutation. The absence of the leaderless linear AS(23/24) and AS(48/49) proteins in Escherichia coli, under all the conditions investigated, supports the idea that the circular backbone is important to stabilize their structure and also indicates the significance of a leader peptide. In fact, the approach taken in this study to generate linear permutated proteins fused to an appropriate partner was sufficient to prevent cellular proteolysis. In this case, the high expression levels found favour their intracellular accumulations as inclusion bodies, which after solubilization showed a propensity to aggregate, thus hindering the specific EK cleavage. This could explain the presence of active hybrid tagged proteins identified in this work. The conserved distribution of hydrophobic and hydrophilic surfaces in the hybrid proteins is responsible for the antibacterial activity. In addition, the opening of the AS-48 molecule between the residues G(23) W(24) connecting the α1/α2 helices, confers greater stability, suggesting that the sequence and/or the free amino acid in the polypeptide chain are critical aspects in the design of new variants.
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Affiliation(s)
- Manuel Montalbán-López
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, C/Fuentenueva s/n, Granada, Spain
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Montalbán-López M, Spolaore B, Pinato O, Martínez-Bueno M, Valdivia E, Maqueda M, Fontana A. Characterization of linear forms of the circular enterocin AS-48 obtained by limited proteolysis. FEBS Lett 2008; 582:3237-42. [PMID: 18760277 DOI: 10.1016/j.febslet.2008.08.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Revised: 08/16/2008] [Accepted: 08/18/2008] [Indexed: 11/24/2022]
Abstract
AS-48 is a 70-residue circular peptide from Enterococcus faecalis with a broad antibacterial activity. Here, we produced by limited proteolysis a protein species carrying a single nicking and fragments of 55 and 38 residues. Nicked AS-48 showed a lower helicity by far-ultraviolet circular dichroism and a reduced stability to thermal denaturation, but it was active against the sensitive bacteria assayed. The fragments also partly retained the biological activity of the intact protein. These results indicate that circularization is not required for the bactericidal activity, but it is important to stabilize the native structure. Moreover, it is possible to reduce the sequence to a minimal AS-48 domain without causing inactivation of this bacteriocin.
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Affiliation(s)
- Manuel Montalbán-López
- Department of Microbiology, Faculty of Sciences, University of Granada, Av. Fuentenueva s/n, 18071 Granada, Spain
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Maqueda M, Sánchez-Hidalgo M, Fernández M, Montalbán-López M, Valdivia E, Martínez-Bueno M. Genetic features of circular bacteriocins produced by Gram-positive bacteria. FEMS Microbiol Rev 2008; 32:2-22. [DOI: 10.1111/j.1574-6976.2007.00087.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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