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Nishihara A, Morimoto N, Sumiyoshi T, Yasumoto S, Kondo M, Kono T, Sakai M, Hikima JI. Inhibition of lysozyme lytic activity by Ivy derived from Photobacterium damselae subsp. piscicida. FISH & SHELLFISH IMMUNOLOGY 2022; 124:280-288. [PMID: 35421575 DOI: 10.1016/j.fsi.2022.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 04/08/2022] [Accepted: 04/09/2022] [Indexed: 06/14/2023]
Abstract
A pseudotuberculosis pathogen, Photobacterium damselae subsp. piscicida (Pdp), has caused enormous economic damage to yellowtail aquaculture in Japan. The Ivy gene has been discovered in plasmid of Pdp, and it has been proposed that it may help bacteria evade lysozyme-mediated lysis during interaction with an animal host. However, the lysozyme-inhibiting activity of Pdp-derived Ivy (Ivy-Pdp) is unknown, and it is unclear whether it acts as a virulence factor for host biophylaxis. In this study, the inhibitory effect of Ivy-Pdp on lysozyme was evaluated by expressing and purifying the recombinant Ivy-Pdp protein (rIvy-Pdp). The rIvy-Pdp protein inhibited hen egg white lysozyme activity in an rIvy-Pdp-concentration-dependent manner, and its inhibitory effect was similar under different temperature and pH conditions. The serum and skin mucus of the yellowtail (which is the host species of Pdp), Japanese flounder, and Nile tilapia showed bacteriolytic activity. In contrast, the addition of rIvy-Pdp inhibited the lytic activity in the serum of these fish species. In particular, it significantly inhibited lytic activity in the serum and skin mucus of Nile tilapia. On the basis of these results, we suggest that Ivy-Pdp is a temperature- and pH-stable lysozyme inhibitor. Additionally, Ivy-Pdp inhibited the lytic activity of lysozyme, which is involved in host biophylaxis. In summary, we inferred that Ivy-Pdp is an important factor that diminishes the sterilization ability of C-type lysozyme when Pdp infects the host.
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Affiliation(s)
- Aki Nishihara
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Natsuki Morimoto
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Takechiyo Sumiyoshi
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Shinya Yasumoto
- Department of Applied Aquabiology, National Fisheries University, Japan Fisheries Research and Education Agency, Yamaguchi 759-6595, Japan
| | - Masakazu Kondo
- Department of Applied Aquabiology, National Fisheries University, Japan Fisheries Research and Education Agency, Yamaguchi 759-6595, Japan
| | - Tomoya Kono
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Masahiro Sakai
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan
| | - Jun-Ichi Hikima
- Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192, Japan.
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2
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Transcriptome-based design of antisense inhibitors potentiates carbapenem efficacy in CRE Escherichia coli. Proc Natl Acad Sci U S A 2020; 117:30699-30709. [PMID: 33199638 DOI: 10.1073/pnas.1922187117] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In recent years, the prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has risen substantially, and the study of CRE resistance mechanisms has become increasingly important for antibiotic development. Although much research has focused on genomic resistance factors, relatively few studies have examined CRE pathogens through changes in gene expression. In this study, we examined the gene expression profile of a CRE Escherichia coli clinical isolate that is sensitive to meropenem but resistant to ertapenem to explore transcriptomic contributions to resistance and to identify gene knockdown targets for carbapenem potentiation. We sequenced total and short RNA to analyze the gene expression response to ertapenem or meropenem treatment and found significant expression changes in genes related to motility, maltodextrin metabolism, the formate hydrogenlyase complex, and the general stress response. To validate these findings, we used our laboratory's Facile Accelerated Specific Therapeutic (FAST) platform to create antisense peptide nucleic acids (PNAs), gene-specific molecules designed to inhibit protein translation. PNAs were designed to inhibit the pathways identified in our transcriptomic analysis, and each PNA was then tested in combination with each carbapenem to assess its effect on the antibiotics' minimum inhibitory concentrations. We observed significant PNA-antibiotic interaction with five different PNAs across six combinations. Inhibition of the genes hycA, dsrB, and bolA potentiated carbapenem efficacy in CRE E. coli, whereas inhibition of the genes flhC and ygaC conferred added resistance. Our results identify resistance factors and demonstrate that transcriptomic analysis is a potent tool for designing antibiotic PNA.
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3
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Grishin AV, Karyagina AS, Vasina DV, Vasina IV, Gushchin VA, Lunin VG. Resistance to peptidoglycan-degrading enzymes. Crit Rev Microbiol 2020; 46:703-726. [PMID: 32985279 DOI: 10.1080/1040841x.2020.1825333] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The spread of bacterial strains resistant to commonly used antibiotics urges the development of novel antibacterial compounds. Ideally, these novel antimicrobials should be less prone to the development of resistance. Peptidoglycan-degrading enzymes are a promising class of compounds with a fundamentally different mode of action compared to traditionally used antibiotics. The difference in the mechanism of action implies differences both in the mechanisms of resistance and the chances of its emergence. To critically assess the potential of resistance development to peptidoglycan-degrading enzymes, we review the available evidence for the development of resistance to these enzymes in vitro, along with the known mechanisms of resistance to lysozyme, bacteriocins, autolysins, and phage endolysins. We conclude that genetic determinants of resistance to peptidoglycan-degrading enzymes are unlikely to readily emerge de novo. However, resistance to these enzymes would probably spread by the horizontal transfer between intrinsically resistant and susceptible species. Finally, we speculate that the higher cost of the therapeutics based on peptidoglycan degrading enzymes compared to classical antibiotics might result in less misuse, which in turn would lead to lower selective pressure, making these antibacterials less prone to resistance development.
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Affiliation(s)
- Alexander V Grishin
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Anna S Karyagina
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russia.,A.N. Belozersky Institute of Physical and Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Daria V Vasina
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Irina V Vasina
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia
| | - Vladimir A Gushchin
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Vladimir G Lunin
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russia
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4
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Juan C, Torrens G, Barceló IM, Oliver A. Interplay between Peptidoglycan Biology and Virulence in Gram-Negative Pathogens. Microbiol Mol Biol Rev 2018; 82:e00033-18. [PMID: 30209071 PMCID: PMC6298613 DOI: 10.1128/mmbr.00033-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The clinical and epidemiological threat of the growing antimicrobial resistance in Gram-negative pathogens, particularly for β-lactams, the most frequently used and relevant antibiotics, urges research to find new therapeutic weapons to combat the infections caused by these microorganisms. An essential previous step in the development of these therapeutic solutions is to identify their potential targets in the biology of the pathogen. This is precisely what we sought to do in this review specifically regarding the barely exploited field analyzing the interplay among the biology of the peptidoglycan and related processes, such as β-lactamase regulation and virulence. Hence, here we gather, analyze, and integrate the knowledge derived from published works that provide information on the topic, starting with those dealing with the historically neglected essential role of the Gram-negative peptidoglycan in virulence, including structural, biogenesis, remodeling, and recycling aspects, in addition to proinflammatory and other interactions with the host. We also review the complex link between intrinsic β-lactamase production and peptidoglycan metabolism, as well as the biological costs potentially associated with the expression of horizontally acquired β-lactamases. Finally, we analyze the existing evidence from multiple perspectives to provide useful clues for identifying targets enabling the future development of therapeutic options attacking the peptidoglycan-virulence interconnection as a key weak point of the Gram-negative pathogens to be used, if not to kill the bacteria, to mitigate their capacity to produce severe infections.
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Affiliation(s)
- Carlos Juan
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Gabriel Torrens
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Isabel Maria Barceló
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
| | - Antonio Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Espases, Instituto de Investigación Sanitaria de Baleares (IdISBa), Palma, Spain
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Transcriptional Responses of Escherichia coli to a Small-Molecule Inhibitor of LolCDE, an Essential Component of the Lipoprotein Transport Pathway. J Bacteriol 2016; 198:3162-3175. [PMID: 27645386 PMCID: PMC5105897 DOI: 10.1128/jb.00502-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/20/2016] [Indexed: 11/20/2022] Open
Abstract
In Gram-negative bacteria, a dedicated machinery consisting of LolABCDE components targets lipoproteins to the outer membrane. We used a previously identified small-molecule inhibitor of the LolCDE complex of Escherichia coli to assess the global transcriptional consequences of interference with lipoprotein transport. Exposure of E. coli to the LolCDE inhibitor at concentrations leading to minimal and significant growth inhibition, followed by transcriptome sequencing, identified a small group of genes whose transcript levels were decreased and a larger group whose mRNA levels increased 10- to 100-fold compared to those of untreated cells. The majority of the genes whose mRNA concentrations were reduced were part of the flagellar assembly pathway, which contains an essential lipoprotein component. Most of the genes whose transcript levels were elevated encode proteins involved in selected cell stress pathways. Many of these genes are involved with envelope stress responses induced by the mislocalization of outer membrane lipoproteins. Although several of the genes whose RNAs were induced have previously been shown to be associated with the general perturbation of the cell envelope by antibiotics, a small subset was affected only by LolCDE inhibition. Findings from this work suggest that the efficiency of the Lol system function may be coupled to a specific monitoring system, which could be exploited in the development of reporter constructs suitable for use for screening for additional inhibitors of lipoprotein trafficking. IMPORTANCE Inhibition of the lipoprotein transport pathway leads to E. coli death and subsequent lysis. Early significant changes in the levels of RNA for a subset of genes identified to be associated with some periplasmic and envelope stress responses were observed. Together these findings suggest that disruption of this key pathway can have a severe impact on balanced outer membrane synthesis sufficient to affect viability.
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Seppola M, Bakkemo KR, Mikkelsen H, Myrnes B, Helland R, Irwin DM, Nilsen IW. Multiple specialised goose-type lysozymes potentially compensate for an exceptional lack of chicken-type lysozymes in Atlantic cod. Sci Rep 2016; 6:28318. [PMID: 27324690 PMCID: PMC4914998 DOI: 10.1038/srep28318] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/31/2016] [Indexed: 01/05/2023] Open
Abstract
Previous analyses of the Atlantic cod genome showed unique combinations of lacking and expanded number of genes for the immune system. The present study examined lysozyme activity, lysozyme gene distribution and expression in cod. Enzymatic assays employing specific bacterial lysozyme inhibitors provided evidence for presence of g-type, but unexpectedly not for c-type lysozyme activity. Database homology searches failed to identify any c-type lysozyme gene in the cod genome or in expressed sequence tags from cod. In contrast, we identified four g-type lysozyme genes (LygF1a-d) constitutively expressed, although differentially, in all cod organs examined. The active site glutamate residue is replaced by alanine in LygF1a, thus making it enzymatic inactive, while LygF1d was found in two active site variants carrying alanine or glutamate, respectively. In vitro and in vivo infection by the intracellular bacterium Francisella noatunensis gave a significantly reduced LygF1a and b expression but increased expression of the LygF1c and d genes as did also the interferon gamma (IFNγ) cytokine. These results demonstrate a lack of c-type lysozyme that is unprecedented among vertebrates. Our results further indicate that serial gene duplications have produced multiple differentially regulated cod g-type lysozymes with specialised functions potentially compensating for the lack of c-type lysozymes.
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Affiliation(s)
- Marit Seppola
- Department of Medical Biology, UiT-The Arctic University of Norway, Tromsø, Norway
| | | | | | | | - Ronny Helland
- Department of Chemistry, UiT-The Arctic University of Norway, Tromsø, Norway
| | - David M Irwin
- Laboratory Medicine &Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Inge W Nilsen
- Faculty of Health Sciences, UiT-The Arctic University of Norway, Tromsø, Norway
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7
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Seppola M, Mikkelsen H, Johansen A, Steiro K, Myrnes B, Nilsen IW. Ultrapure LPS induces inflammatory and antibacterial responses attenuated in vitro by exogenous sera in Atlantic cod and Atlantic salmon. FISH & SHELLFISH IMMUNOLOGY 2015; 44:66-78. [PMID: 25655332 DOI: 10.1016/j.fsi.2015.01.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 01/12/2015] [Accepted: 01/22/2015] [Indexed: 06/04/2023]
Abstract
Phagocyte recognition of lipopolysaccharide (LPS) is an early key event for triggering the host innate immune response necessary for clearance of invading bacteria. The ability of fishes to recognise LPS has been questioned as contradictory results have been presented. We show here that monocyte/macrophage cultures from Atlantic cod (Gadus morhua) and Atlantic salmon (Salmo salar) respond with an increased expression of inflammatory and antibacterial genes to both crude and ultrapure Escherichia coli LPS. Crude LPS produces higher induction than the ultrapure LPS type in both species in vitro as well as in vivo in cod injected with LPS. Crude LPS gave, in contrast to ultrapure LPS, an additional weak up-regulation of antiviral genes in salmon macrophages, most likely because of contaminants in the LPS preparation. Increased levels of chicken (c)-type lysozyme transcripts and enzyme activity were measured in salmon macrophages following ultrapure LPS stimulation demonstrating not only increased transcription but also translation. Simultaneous use and even pre-treatment with bovine sera suppressed the LPS-induced expression thereby reflecting the presence of transcription inhibitory components in sera. Together, these findings show that both cod and salmon recognise LPS per se and that the observed induction is highly dependent on the absence of sera.
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Affiliation(s)
- Marit Seppola
- Norwegian College of Fishery Science, The Arctic University of Norway, P.O. Box 6050, 9037 Tromsø, Norway.
| | - Helene Mikkelsen
- The Northern Norway Regional Health Authority, P.O. Box 6426, 9294 Tromsø, Norway
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8
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Dostal SM, Fang Y, Guerrette JC, Scanlon TC, Griswold KE. Genetically enhanced lysozyme evades a pathogen derived inhibitory protein. ACS Chem Biol 2015; 10:1110-7. [PMID: 25607237 DOI: 10.1021/cb500976y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The accelerating spread of drug-resistant bacteria is creating demand for novel antibiotics. Bactericidal enzymes, such as human lysozyme (hLYZ), are interesting drug candidates due to their inherent catalytic nature and lack of susceptibility to the resistance mechanisms typically directed toward chemotherapeutics. However, natural antibacterial enzymes have their own limitations. For example, hLYZ is susceptible to pathogen derived inhibitory proteins, such as Escherichia coli Ivy. Here, we describe proof of concept studies demonstrating that hLYZ can be effectively redesigned to evade this potent lysozyme inhibitor. Large combinatorial libraries of hLYZ were analyzed using an innovative screening platform based on microbial coculture in hydrogel microdroplets. Isolated hLYZ variants were orders of magnitude less susceptible to E. coli Ivy yet retained high catalytic proficiency and inherent antibacterial activity. Interestingly, the engineered escape variants showed a disadvantageous increase in susceptibility to the related Ivy ortholog from Pseudomonas aeruginosa as well as an unrelated E. coli inhibitory protein, MliC. Thus, while we have achieved our original objective with respect to escaping E. coli Ivy, engineering hLYZ for broad-spectrum evasion of proteinaceous inhibitors will require consideration of the complex and varied determinants that underlie molecular recognition by these emerging virulence factors.
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Affiliation(s)
- Sarah M. Dostal
- Thayer School of Engineering at Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, United States
| | - Yongliang Fang
- Thayer School of Engineering at Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, United States
| | - Jonathan C. Guerrette
- Thayer School of Engineering at Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, United States
| | - Thomas C. Scanlon
- Thayer School of Engineering at Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, United States
| | - Karl E. Griswold
- Thayer School of Engineering at Dartmouth College, 14 Engineering Drive, Hanover, New Hampshire 03755, United States
- Program in Molecular and Cellular Biology, Dartmouth College, Hanover, New Hampshire 03755, United States
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9
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Derde M, Guérin-Dubiard C, Lechevalier V, Cochet MF, Jan S, Baron F, Gautier M, Vié V, Nau F. Dry-heating of lysozyme increases its activity against Escherichia coli membranes. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:1692-1700. [PMID: 24450740 DOI: 10.1021/jf405155p] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
For food as well as for medical applications, there is a growing interest in novel and natural antimicrobial molecules. Lysozyme is a promising candidate for the development of such molecules. This protein is largely studied and known for its muramidase activity against Gram-positive bacteria, but it also shows antimicrobial activity against Gram-negative bacteria, especially when previously modified. In this study, the activity of dry-heated lysozyme (DH-L) against Escherichia coli has been investigated and compared to that of native lysozyme (N-L). Whereas N-L only delays bacterial growth, DH-L causes an early-stage population decrease. The accompanying membrane permeabilization suggests that DH-L induces either larger pores or more pores in the outer membrane as compared to N-L, as well as more ion channels in the inner membrane. The strong morphological modifications observed by optical microscopy and atomic force microscopy when E. coli cells are treated with DH-L are consistent with the suggested disturbances of membrane integrity. The higher hydrophobicity, surface activity, and positive charge induced by dry-heating could be responsible for the increased activity of DH-L on the E. coli membranes.
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Affiliation(s)
- Melanie Derde
- Agrocampus Ouest, UMR1253 Science et technologie du lait et de l'œuf , F-35042 Rennes, France
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10
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Using a bacteriocin structure to engineer a phage lysin that targets Yersinia pestis. Biochem Soc Trans 2013; 40:1503-6. [PMID: 23176506 DOI: 10.1042/bst20120209] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Purified phage lysins present an alternative to traditional antibiotics and work by hydrolysing peptidoglycan. Phage lysins have been developed against Gram-positive pathogens such as Bacillus anthracis and Streptococcus pneumoniae, where the peptidoglycan layer is exposed on the cell surface. Addition of the lysin to a bacterial culture results in rapid death of the organism. Gram-negative bacteria are resistant to phage lysins because they contain an outer membrane that protects the peptidoglycan from degradation. We solved crystal structures of a Yersinia pestis outer-membrane protein and the bacteriocin that targets it, which informed engineering of a bacterial-phage hybrid lysin that can be transported across the outer membrane to kill specific Gram-negative bacteria. This work provides a template for engineering phage lysins against a wide variety of bacterial pathogens.
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11
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Myrnes B, Seppola M, Johansen A, Overbø K, Callewaert L, Vanderkelen L, Michiels CW, Nilsen IW. Enzyme characterisation and gene expression profiling of Atlantic salmon chicken- and goose-type lysozymes. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 40:11-19. [PMID: 23396098 DOI: 10.1016/j.dci.2013.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 01/13/2013] [Accepted: 01/14/2013] [Indexed: 06/01/2023]
Abstract
Lysozymes represent important innate immune components against bacteria. In this study, Atlantic salmon (Salmo salar) goose (g-) and chicken (c-) types of lysozyme were subjected to protein characterisations and tissue expression analyses. Specific bacterial protein inhibitors of g- and c-type lysozymes were employed to discriminate between respective enzyme activities. Blood, gills and liver contained activities exclusive for the g-type lysozyme. Only haematopoietic organs (head kidney and spleen) contained enzyme activities of both g- and c-lysozyme enzymes and c-type activity was not found outside these organs. Gene transcript levels proportional to enzyme activity levels were detected for the g-type lysozyme but not for the c-type. In vitro studies revealed significant induction of c-type gene expression and enzyme activity in macrophages after incubation with lipopolysaccharide (LPS) while expression of the g-type lysozyme gene was unaffected. The activity of purified native c-type enzyme was profoundly reduced by divalent cations and displayed low tolerance to monovalent cations, while the native g-type lysozyme was stimulated by monovalent cations and tolerated low concentrations of divalent cations. Activities of both enzymes increased with temperature elevations up to 60°C. The native g-type lysozyme responses to temperature in particular are in apparent conflict to the ones for the recombinant salmon g-lysozyme. Our results imply separate expression regulations and different functions of c- and g-type lysozymes in salmon. LPS-induced expression of c-type lysozyme and broad constitutive tissue distribution of g-type lysozyme in salmon is different from findings in other studied fish species.
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Affiliation(s)
- Bjørnar Myrnes
- Marine Biotechnology, Nofima, Muninbakken 9-13, 9291 Tromsø, Norway
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12
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Leysen S, Vanderkelen L, Weeks SD, Michiels CW, Strelkov SV. Structural basis of bacterial defense against g-type lysozyme-based innate immunity. Cell Mol Life Sci 2013; 70:1113-22. [PMID: 23086131 PMCID: PMC11113182 DOI: 10.1007/s00018-012-1184-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/21/2012] [Accepted: 09/27/2012] [Indexed: 10/27/2022]
Abstract
Gram-negative bacteria can produce specific proteinaceous inhibitors to defend themselves against the lytic action of host lysozymes. So far, four different lysozyme inhibitor families have been identified. Here, we report the crystal structure of the Escherichia coli periplasmic lysozyme inhibitor of g-type lysozyme (PliG-Ec) in complex with Atlantic salmon g-type lysozyme (SalG) at a resolution of 0.95 Å, which is exceptionally high for a complex of two proteins. The structure reveals for the first time the mechanism of g-type lysozyme inhibition by the PliG family. The latter contains two specific conserved regions that are essential for its inhibitory activity. The inhibitory complex formation is based on a double 'key-lock' mechanism. The first key-lock element is formed by the insertion of two conserved PliG regions into the active site of the lysozyme. The second element is defined by a distinct pocket of PliG accommodating a lysozyme loop. Computational analysis indicates that this pocket represents a suitable site for small molecule binding, which opens an avenue for the development of novel antibacterial agents that suppress the inhibitory activity of PliG.
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Affiliation(s)
- S. Leysen
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - L. Vanderkelen
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - S. D. Weeks
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
| | - C. W. Michiels
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - S. V. Strelkov
- Laboratory for Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
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13
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Lamppa JW, Tanyos SA, Griswold KE. Engineering Escherichia coli for soluble expression and single step purification of active human lysozyme. J Biotechnol 2012; 164:1-8. [PMID: 23220215 DOI: 10.1016/j.jbiotec.2012.11.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/07/2012] [Accepted: 11/15/2012] [Indexed: 10/27/2022]
Abstract
Genetically engineered variants of human lysozyme represent promising leads in the battle against drug-resistant bacterial pathogens, but early stage development and testing of novel lysozyme variants is constrained by the lack of a robust, scalable and facile expression system. While wild type human lysozyme is reportedly produced at 50–80 kg per hectare of land in recombinant rice, this plant-based system is not readily scaled down to bench top production, and it is therefore not suitable for development and characterization of novel lysozyme variants. Here, we describe a novel and efficient expression system capable of producing folded, soluble and functional human lysozyme in Escherichia coli cells. To achieve this goal, we simultaneously co-express multiple protein folding chaperones as well as harness the lysozyme inhibitory protein, Ivy. Our strategy exploits E. coli's ease of culture, short doubling time, and facile genetics to yield upwards of 30 mg/l of soluble lysozyme in a bioreactor system, a 3000-fold improvement over prior efforts in E. coli. Additionally, molecular interactions between lysozyme and a his-tagged Ivy allows for one-step purification by IMAC, yielding as much as 21 mg/l of purified enzyme. We anticipate that our expression and purification platform will facilitate further development of engineered lysozymes having utility in disease treatment and other practical applications.
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Affiliation(s)
- John W Lamppa
- Thayer School of Engineering, Dartmouth College, Hanover, NH 03755, USA
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14
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Abstract
Phage lysis is a ubiquitous biological process, the most frequent cytocidal event in the biosphere. Lysis of Gram-negative hosts has been shown to require holins and endolysins, which attack the cytoplasmic membrane and peptidoglycan, respectively. Recently, a third class of lysis proteins, the spanins, was identified. The first spanins to be characterized were λ Rz and Rz1, an integral cytoplasmic membrane protein and an outer membrane lipoprotein, respectively. Previous work has shown that Rz and Rz1 form complexes that span the entire periplasm. Phase-contrast video microscopy was used to record the morphological changes involved in the lysis of induced λ lysogens carrying prophages with either the λ canonical holin-endolysin system or the phage 21 pinholin-signal anchor release (SAR) endolysin system. In the former, rod morphology persisted until the instant of an explosive polar rupture, immediately emptying the cell of its contents. In contrast, in pinholin-SAR endolysin lysis, the cell began to shorten and thicken uniformly, with the resultant rounded cell finally bursting. In both cases, lysis failed to occur in inductions of isogenic prophages carrying null mutations in the spanin genes. In both systems, instead of an envelope rupture, the induced cells were converted from a rod shape to a spherical form. A functional GFPΦRz chimera was shown to exhibit a punctate distribution when coexpressed with Rz1, despite the absence of endolysin function. A model is proposed in which the spanins carry out the essential step of disrupting the outer membrane, in a manner regulated by the state of the peptidoglycan layer.
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15
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Müller I, Gernold M, Schneider B, Geider K. Expression of lysozymes from Erwinia amylovora phages and Erwinia genomes and inhibition by a bacterial protein. J Mol Microbiol Biotechnol 2012; 22:59-70. [PMID: 22456518 DOI: 10.1159/000335878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Genes coding for lysozyme-inhibiting proteins (Ivy) were cloned from the chromosomes of the plant pathogens Erwinia amylovora and Erwinia pyrifoliae. The product interfered not only with activity of hen egg white lysozyme, but also with an enzyme from E. amylovora phage ΦEa1h. We have expressed lysozyme genes from the genomes of three Erwinia species in Escherichia coli. The lysozymes expressed from genes of the E. amylovora phages ΦEa104 and ΦEa116, Erwinia chromosomes and Arabidopsis thaliana were not affected by Ivy. The enzyme from bacteriophage ΦEa1h was fused at the N- or C-terminus to other peptides. Compared to the intact lysozyme, a His-tag reduced its lytic activity about 10-fold and larger fusion proteins abolished activity completely. Specific protease cleavage restored lysozyme activity of a GST-fusion. The bacteriophage-encoded lysozymes were more active than the enzymes from bacterial chromosomes. Viral lyz genes were inserted into a broad-host range vector, and transfer to E. amylovora inhibited cell growth. Inserted in the yeast Pichia pastoris, the ΦEa1h-lysozyme was secreted and also inhibited by Ivy. Here we describe expression of unrelated cloned 'silent' lyz genes from Erwinia chromosomes and a novel interference of bacterial Ivy proteins with a viral lysozyme.
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Affiliation(s)
- Ina Müller
- Julius Kühn-Institut, Institut für Pflanzenschutz in Obst- und Weinbau, Dossenheim, Deutschland
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16
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Goose-type lysozyme inhibitor (PliG) enhances survival of Escherichia coli in goose egg albumen. Appl Environ Microbiol 2011; 77:4697-9. [PMID: 21602367 DOI: 10.1128/aem.00427-11] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The goose-type lysozyme inhibitor PliG enhances the survival of Escherichia coli in goose but not in chicken egg white, which contains goose- and chicken-type lysozymes, respectively. These results indicate that both the type of host lysozyme and the type of bacterial lysozyme inhibitor may affect bacterium-host interactions.
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17
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Vanderkelen L, Van Herreweghe JM, Vanoirbeek KGA, Baggerman G, Myrnes B, Declerck PJ, Nilsen IW, Michiels CW, Callewaert L. Identification of a bacterial inhibitor against g-type lysozyme. Cell Mol Life Sci 2011; 68:1053-64. [PMID: 20734102 PMCID: PMC11115080 DOI: 10.1007/s00018-010-0507-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/12/2010] [Accepted: 08/10/2010] [Indexed: 01/17/2023]
Abstract
Lysozymes are antibacterial effectors of the innate immune system in animals that hydrolyze peptidoglycan. Bacteria have evolved protective mechanisms that contribute to lysozyme tolerance such as the production of lysozyme inhibitors, but only inhibitors of chicken (c-) and invertebrate (i-) type lysozyme have been identified. We here report the discovery of a novel Escherichia coli inhibitor specific for goose (g-) type lysozymes, which we designate PliG (periplasmic lysozyme inhibitor of g-type lysozyme). Although it does not inhibit c- or i-type lysozymes, PliG shares a structural sequence motif with the previously described PliI and MliC/PliC lysozyme inhibitor families, suggesting a common ancestry and mode of action. Deletion of pliG increased the sensitivity of E. coli to g-type lysozyme. The existence of inhibitors against all major types of animal lysozyme and their contribution to lysozyme tolerance suggest that lysozyme inhibitors may play a role in bacterial interactions with animal hosts.
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Affiliation(s)
- L. Vanderkelen
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - J. M. Van Herreweghe
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - K. G. A. Vanoirbeek
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - G. Baggerman
- Prometa, Interfaculty Centre for Proteomics and Metabolomics, Katholieke Universiteit Leuven, O&N II Herestraat 49, 3000 Leuven, Belgium
| | - B. Myrnes
- Fish Health and Marine Bioprospecting, Nofima Marin, P.O. Box 6122, 9291 Tromsø, Norway
| | - P. J. Declerck
- Laboratory for Pharmaceutical Biology, Katholieke Universiteit Leuven, O&N II Herestraat 49, 3000 Leuven, Belgium
| | - I. W. Nilsen
- Fish Health and Marine Bioprospecting, Nofima Marin, P.O. Box 6122, 9291 Tromsø, Norway
| | - C. W. Michiels
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - L. Callewaert
- Laboratory of Food Microbiology and Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
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18
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Voet A, Callewaert L, Ulens T, Vanderkelen L, Vanherreweghe JM, Michiels CW, De Maeyer M. Structure based discovery of small molecule suppressors targeting bacterial lysozyme inhibitors. Biochem Biophys Res Commun 2011; 405:527-32. [PMID: 21256115 DOI: 10.1016/j.bbrc.2011.01.053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Accepted: 01/15/2011] [Indexed: 11/28/2022]
Abstract
The production of lysozyme inhibitors, competitively binding to the lysozyme active site, is a bacterial strategy to prevent the lytic activity of host lysozymes. Therefore, suppression of the lysozyme-inhibitor interaction is an interesting new approach for drug development since restoration of the bacterial lysozyme sensitivity will support bacterial clearance from the infected sites. Using molecular modelling techniques the interaction of the Salmonella PliC inhibitor with c-type lysozyme was studied and a protein-protein interaction based pharmacophore model was created. This model was used as a query to identify molecules, with potential affinity for the target, and subsequently, these molecules were filtered using molecular docking. The retained molecules were validated as suppressors of lysozyme inhibitory proteins using in vitro experiments revealing four active molecules.
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Affiliation(s)
- Arnout Voet
- Laboratory for Biomolecular Modelling and BioMacS, Katholieke Universiteit Leuven, Celestijnenlaan 200G bus 2403, 3001 Heverlee, Leuven, Belgium.
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19
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Leysen S, Van Herreweghe JM, Callewaert L, Heirbaut M, Buntinx P, Michiels CW, Strelkov SV. Molecular basis of bacterial defense against host lysozymes: X-ray structures of periplasmic lysozyme inhibitors PliI and PliC. J Mol Biol 2010; 405:1233-45. [PMID: 21146533 DOI: 10.1016/j.jmb.2010.12.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 11/25/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
Abstract
Lysozymes play a key role in the innate immune system of vertebrates and invertebrates by hydrolyzing peptidoglycan, a vital component of the bacterial cell wall. Gram-negative bacteria produce various types of lysozyme inhibitors that allow them to survive the bactericidal action of lysozyme when their outer membrane is permeabilized. So far, three lysozyme inhibitor families have been described: the Ivy (inhibitor of vertebrate lysozyme) family, the MliC/PliC (membrane-associated/periplasmic lysozyme inhibitor of C-type lysozyme) family, and the PliI (periplasmic lysozyme inhibitor of I-type lysozyme) family. Here, we report high-resolution crystal structures of Salmonella typhimurium PliC (PliC-St) and Aeromonas hydrophila PliI (PliI-Ah). The structure of PliI-Ah is the first in the recently discovered PliI family of lysozyme inhibitors, while the structure of PliC-St is the first structure of a periplasmic lysozyme inhibitor from the PliC/MliC family. Using small-angle X-ray scattering, we demonstrate that both PliC-St and PliI-Ah form stable dimers in solution. The functional dimer architecture of PliC-St is very different from that of the recently described MliC from Pseudomonas aeruginosa (MliC-Pa), despite the close resemblance of their monomers. Furthermore, PliI-Ah has distinctly different monomer and dimer folds compared to PliC, MliC, and Ivy proteins. Site-directed mutagenesis suggests that the inhibitory action of PliI-Ah proceeds via an insertion of a loop containing the conserved SGxY motif into the active center of I-type lysozymes. This motif is related to the functional SGxxY motif found in the MliC/PliC family.
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Affiliation(s)
- S Leysen
- Laboratory for Biocrystallography, Department of Pharmaceutical Sciences, Katholieke Universiteit Leuven, Herestraat 49 bus 822, 3000 Leuven, Belgium
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20
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Van Herreweghe JM, Vanderkelen L, Callewaert L, Aertsen A, Compernolle G, Declerck PJ, Michiels CW. Lysozyme inhibitor conferring bacterial tolerance to invertebrate type lysozyme. Cell Mol Life Sci 2010; 67:1177-88. [PMID: 20049505 PMCID: PMC11115509 DOI: 10.1007/s00018-009-0241-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 11/30/2009] [Accepted: 12/18/2009] [Indexed: 10/20/2022]
Abstract
Invertebrate (I-) type lysozymes, like all other known lysozymes, are dedicated to the hydrolysis of peptidoglycan, the major bacterial cell wall polymer, thereby contributing to the innate immune system and/or digestive system of invertebrate organisms. Bacteria on the other hand have developed several protective strategies against lysozymes, including the production of periplasmic and/or membrane-bound lysozyme inhibitors. The latter have until now only been described for chicken (C-) type lysozymes. We here report the discovery, purification, identification and characterization of the first bacterial specific I-type lysozyme inhibitor from Aeromonas hydrophila, which we designate PliI (periplasmic lysozyme inhibitor of the I-type lysozyme). PliI has homologs in several proteobacterial genera and contributes to I-type lysozyme tolerance in A. hydrophila in the presence of an outer membrane permeabilizer. These and previous findings on C-type lysozyme inhibitors suggest that bacterial lysozyme inhibitors may have an important function, for example, in bacteria-host interactions.
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Affiliation(s)
- J. M. Van Herreweghe
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - L. Vanderkelen
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - L. Callewaert
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - A. Aertsen
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
| | - G. Compernolle
- Laboratory for Pharmaceutical Biology, Katholieke Universiteit Leuven, O&N II Herestraat 49, 3000 Leuven, Belgium
| | - P. J. Declerck
- Laboratory for Pharmaceutical Biology, Katholieke Universiteit Leuven, O&N II Herestraat 49, 3000 Leuven, Belgium
| | - C. W. Michiels
- Laboratory of Food Microbiology, Leuven Food Science and Nutrition Research Centre (LFoRCe), Katholieke Universiteit Leuven, Kasteelpark Arenberg 22, 3001 Leuven, Belgium
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21
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22
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Detection of a lysozyme inhibitor in Proteus mirabilis by a new reverse zymogram method. Appl Environ Microbiol 2008; 74:4978-81. [PMID: 18539812 DOI: 10.1128/aem.00219-08] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A reverse zymogram method for the detection of bacterial lysozyme inhibitors was developed. This method was validated by using a periplasmic protein extract of Escherichia coli containing a known inhibitor and subsequently led to the detection of a new proteinaceous hen egg white lysozyme inhibitor in Proteus mirabilis.
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23
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Role of the lysozyme inhibitor Ivy in growth or survival of Escherichia coli and Pseudomonas aeruginosa bacteria in hen egg white and in human saliva and breast milk. Appl Environ Microbiol 2008; 74:4434-9. [PMID: 18515493 DOI: 10.1128/aem.00589-08] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ivy is a lysozyme inhibitor that protects Escherichia coli against lysozyme-mediated cell wall hydrolysis when the outer membrane is permeabilized by mutation or by chemical or physical stress. In the current work, we have investigated whether Ivy is necessary for the survival or growth of E. coli MG1655 and Pseudomonas aeruginosa PAO1 in hen egg white and in human saliva and breast milk, which are naturally rich in lysozyme and in membrane-permeabilizing components. Wild-type E. coli was able to grow in saliva and breast milk but showed partial inactivation in egg white. The knockout of Ivy did not affect growth in breast milk but slightly increased sensitivity to egg white and caused hypersensitivity to saliva, resulting in the complete inactivation of 10(4) CFU ml(-1) of bacteria within less than 5 hours. The depletion of lysozyme from saliva completely restored the ability of the ivy mutant to grow like the parental strain. P. aeruginosa, in contrast, showed growth in all three substrates, which was not affected by the knockout of Ivy production. These results indicate that lysozyme inhibitors like Ivy promote bacterial survival or growth in particular lysozyme-rich secretions and suggest that they may promote the bacterial colonization of specific niches in the animal host.
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24
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Kyomuhendo P, Nilsen IW, Brandsdal BO, Smalås AO. Structural evidence for lack of inhibition of fish goose-type lysozymes by a bacterial inhibitor of lysozyme. J Mol Model 2008; 14:777-88. [PMID: 18491152 DOI: 10.1007/s00894-008-0317-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 04/14/2008] [Indexed: 11/29/2022]
Abstract
It is known that bacteria contain inhibitors of lysozyme activity. The recently discovered Escherichia coli inhibitor of vertebrate lysozyme (Ivy) and its potential interactions with several goose-type (g-type) lysozymes from fish were studied using functional enzyme assays, comparative homology modelling, protein-protein docking, and molecular dynamics simulations. Enzyme assays carried out on salmon g-type lysozyme revealed a lack of inhibition by Ivy. Detailed analysis of the complexes formed between Ivy and both hen egg white lysozyme (HEWL) and goose egg white lysozyme (GEWL) suggests that electrostatic interactions make a dominant contribution to inhibition. Comparison of three dimensional models of aquatic g-type lysozymes revealed important insertions in the beta domain, and specific sequence substitutions yielding altered electrostatic surface properties and surface curvature at the protein-protein interface. Thus, based on structural homology models, we propose that Ivy is not effective against any of the known fish g-type lysozymes. Docking studies suggest a weaker binding mode between Ivy and GEWL compared to that with HEWL, and our models explain the mechanistic necessity for conservation of a set of residues in g-type lysozymes as a prerequisite for inhibition by Ivy.
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Affiliation(s)
- Peter Kyomuhendo
- Marine Biotechnology and Fish Health, Norwegian Institute of Fisheries and Aquaculture, PO Box 6122, 9291 Tromsø, Norway
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25
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Callewaert L, Aertsen A, Deckers D, Vanoirbeek KGA, Vanderkelen L, Van Herreweghe JM, Masschalck B, Nakimbugwe D, Robben J, Michiels CW. A new family of lysozyme inhibitors contributing to lysozyme tolerance in gram-negative bacteria. PLoS Pathog 2008; 4:e1000019. [PMID: 18369469 PMCID: PMC2267010 DOI: 10.1371/journal.ppat.1000019] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 01/31/2008] [Indexed: 11/21/2022] Open
Abstract
Lysozymes are ancient and important components of the innate immune system of animals that hydrolyze peptidoglycan, the major bacterial cell wall polymer. Bacteria engaging in commensal or pathogenic interactions with an animal host have evolved various strategies to evade this bactericidal enzyme, one recently proposed strategy being the production of lysozyme inhibitors. We here report the discovery of a novel family of bacterial lysozyme inhibitors with widespread homologs in gram-negative bacteria. First, a lysozyme inhibitor was isolated by affinity chromatography from a periplasmic extract of Salmonella Enteritidis, identified by mass spectrometry and correspondingly designated as PliC (periplasmic lysozyme inhibitor of c-type lysozyme). A pliC knock-out mutant no longer produced lysozyme inhibitory activity and showed increased lysozyme sensitivity in the presence of the outer membrane permeabilizing protein lactoferrin. PliC lacks similarity with the previously described Escherichia coli lysozyme inhibitor Ivy, but is related to a group of proteins with a common conserved COG3895 domain, some of them predicted to be lipoproteins. No function has yet been assigned to these proteins, although they are widely spread among the Proteobacteria. We demonstrate that at least two representatives of this group, MliC (membrane bound lysozyme inhibitor of c-type lysozyme) of E. coli and Pseudomonas aeruginosa, also possess lysozyme inhibitory activity and confer increased lysozyme tolerance upon expression in E. coli. Interestingly, mliC of Salmonella Typhi was picked up earlier in a screen for genes induced during residence in macrophages, and knockout of mliC was shown to reduce macrophage survival of S. Typhi. Based on these observations, we suggest that the COG3895 domain is a common feature of a novel and widespread family of bacterial lysozyme inhibitors in gram-negative bacteria that may function as colonization or virulence factors in bacteria interacting with an animal host. Lysozyme is an ancient bactericidal enzyme that is part of the antibacterial defense system of vertebrate and invertebrate animals. Bacteria colonizing or infecting an animal host have developed various ways to overcome lysozyme action, a recently proposed mechanism being the production of lysozyme inhibitors. However, the only high affinity bacterial lysozyme inhibitor known thus far is produced only in few bacteria, and this raised questions about their wider relevance in bacteria–host interactions. We here report the discovery of a novel and distinct family of bacterial lysozyme inhibitors that is widely distributed among the Proteobacteria, including several major pathogens. The family comprises periplasmic as well as membrane-bound inhibitors, and both types contribute to lysozyme tolerance of bacterial cells, as we experimentally demonstrate for the periplasmic inhibitor from Salmonella Typhimurium and the membrane-bound inhibitors from Escherichia coli and Pseudomonas aeruginosa. Interestingly, a gene encoding one of the newly identified inhibitors has been previously found to promote macrophage survival of Salmonella Typhi. The widespread occurrence of lysozyme inhibitors in bacteria is likely to reflect their functional importance in a wide range of bacteria–host interactions. As such, they are also attractive novel targets for antibacterial drug development.
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Affiliation(s)
- Lien Callewaert
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Abram Aertsen
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Daphne Deckers
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Kristof G. A. Vanoirbeek
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Lise Vanderkelen
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Joris M. Van Herreweghe
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Barbara Masschalck
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Dorothy Nakimbugwe
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Johan Robben
- Biomedical Research Institute (BIOMED), Hasselt University and Transnationale Universiteit Limburg, School of Life Sciences, Diepenbeek, Belgium
| | - Chris W. Michiels
- Laboratory of Food Microbiology, Department of Microbial and Molecular Systems (M2S), Katholieke Universiteit Leuven, Leuven, Belgium
- * E-mail:
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