1
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Silverman GJ, Azzouz DF, Gisch N, Amarnani A. The gut microbiome in systemic lupus erythematosus: lessons from rheumatic fever. Nat Rev Rheumatol 2024; 20:143-157. [PMID: 38321297 DOI: 10.1038/s41584-023-01071-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2023] [Indexed: 02/08/2024]
Abstract
For more than a century, certain bacterial infections that can breach the skin and mucosal barriers have been implicated as common triggers of autoimmune syndromes, especially post-infection autoimmune diseases that include rheumatic fever and post-streptococcal glomerulonephritis. However, only in the past few years has the importance of imbalances within our own commensal microbiota communities, and within the gut, in the absence of infection, in promoting autoimmune pathogenesis become fully appreciated. A diversity of species and mechanisms have been implicated, including disruption of the gut barrier. Emerging data suggest that expansions (or blooms) of pathobiont species are involved in autoimmune pathogenesis and stimulate clonal expansion of T cells and B cells that recognize microbial antigens. This Review discusses the relationship between the gut microbiome and the immune system, and the potential consequence of disrupting the community balance in terms of autoimmune development, focusing on systemic lupus erythematosus. Notably, inter-relationships between expansions of certain members within gut microbiota communities and concurrent autoimmune responses bear features reminiscent of classical post-infection autoimmune disease. From such insights, new therapeutic opportunities are being considered to restore the balance within microbiota communities or re-establishing the gut-barrier integrity to reinforce immune homeostasis in the host.
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Affiliation(s)
- Gregg J Silverman
- Department of Medicine, NYU Grossman School of Medicine, New York, NY, USA.
| | - Doua F Azzouz
- Department of Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Abhimanyu Amarnani
- Department of Medicine, NYU Grossman School of Medicine, New York, NY, USA
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2
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Nur N, Suwanto A, Meryandini A, Suhartono MT, Puspitasari E, Kim HK. Cloning and characterization of an acidic lipase from a lipolytic bacterium in tempeh. J Genet Eng Biotechnol 2023; 21:157. [PMID: 38038870 PMCID: PMC10692048 DOI: 10.1186/s43141-023-00611-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023]
Abstract
BACKGROUND Lipases have emerged as essential biocatalysts, having the ability to contribute to a wide range of industrial applications. Microbial lipases have garnered significant industrial attention due to their stability, selectivity, and broad substrate specificity. In the previous study, a unique lipolytic bacterium (Micrococcus luteus EMP48-D) was isolated from tempeh. It turns out the bacteria produce an acidic lipase, which is important in biodiesel production. Our main objectives were to clone the acidic lipase and investigate its potential in biodiesel production. RESULT In this study, the gene encoding a lipase from M. luteus EMP48-D was cloned and expressed heterologously in Escherichia coli. To our knowledge, this is the first attempt at the cloning and expression of the lipase gene from Micrococcus luteus. The amino acid sequence was deduced from the nucleotide sequence (1356 bp) corresponded to a protein of 451 amino acid residues with a molecular weight of about 40 kDa. The presence of a signal peptide suggested that the protein was extracellular. A sequence analysis revealed that the protein had a lipase-specific Gly-X-Ser-X-Gly motif. The enzyme was identified as an acidic lipase with a pH preference of 5.0. Fatty acid preferences for enzyme activities were C8 and C12 (p-nitrophenyl esters), with optimum temperatures at 30-40 °C and still remaining active at 80°C. The enzyme was also shown to convert up to 70% of the substrate into fatty acid methyl ester. CONCLUSION The enzyme was a novel acidic lipase that demonstrated both hydrolytic and transesterification reactions. It appeared particularly promising for the synthesis of biodiesel as this enzyme's catalytic reaction was optimum at low temperatures and was still active at high temperatures.
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Affiliation(s)
- Naswandi Nur
- Research Center for Applied Microbiology, National Research and Innovation Agency, Jl Raya Jakarta-Bogor KM 46, Cibinong, Bogor, 16911, West Java, Indonesia.
| | - Antonius Suwanto
- Department of Biology, Faculty of Mathematics and Natural Science, IPB University, Bogor, 16680, Indonesia
| | - Anja Meryandini
- Department of Biology, Faculty of Mathematics and Natural Science, IPB University, Bogor, 16680, Indonesia
| | - Maggy Thenawidjaja Suhartono
- Department of Food Science and Technology, Faculty of Agricultural Engineering and Technology, IPB University, Bogor, 16680, Indonesia
| | - Esti Puspitasari
- Department of Biotechnology Research and Development, PT Wilmar Benih Indonesia, Bekasi, 17530, Indonesia
| | - Hyung Kwoun Kim
- Division of Biotechnology, The Catholic University of Korea, Bucheon, 420-743, Republic of Korea
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3
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Davray D, Kulkarni R. In-silico functional analysis of hypothetical proteins from Lactiplantibacillus plantarum plasmids reveals enrichment of cell envelope proteins. Plasmid 2023; 127:102693. [PMID: 37257733 DOI: 10.1016/j.plasmid.2023.102693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 05/19/2023] [Accepted: 05/25/2023] [Indexed: 06/02/2023]
Abstract
Lactiplantibacillus plantarum is one of the important species of lactic acid bacterium (LAB) found in diverse environments, with many strains exhibiting probiotic properties. In our previous study, 41.6% of protein families (PFs) encoded by 395 plasmids from several L. plantarum strains were found to be hypothetical proteins with no predicted function. This study aimed at predicting the functions of these 647 hypothetical proteins using 21 different bioinformatics methods. As a result, 160 PFs could be newly annotated. A lower proportion of plasmid-specific functions was annotated as compared to the functions shared between plasmids and chromosomes. Also, hypothetical proteins were less conserved than the annotated proteins across L.plantarum plasmids. Based on the subcellular localization, cell envelope proteins represented the biggest category in the newly annotated proteins. Transporters (112 PFs) which was a part of cell envelop proteins represented the largest functional group. Additionally, 40 and 25 other PFs were predicted to contain signal peptides and transmembrane helices, respectively. We speculate that such hypothetical proteins might be involved in the transport of various chemicals and environmental interactions in L. plantarum. In the future, functional characterization of these proteins through wet-lab experimental approach can provide novel insights into their contribution to the physiology, probiotic properties, and industrial utility of these bacteria.
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Affiliation(s)
- Dimple Davray
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India
| | - Ram Kulkarni
- Symbiosis School of Biological Sciences, Symbiosis International (Deemed University), Lavale, Pune 412115, India.
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4
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Roden A, Engelin MK, Pos KM, Geertsma ER. Membrane-anchored substrate binding proteins are deployed in secondary TAXI transporters. Biol Chem 2023:hsz-2022-0337. [PMID: 36916166 DOI: 10.1515/hsz-2022-0337] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 02/10/2023] [Indexed: 03/16/2023]
Abstract
Substrate-binding proteins (SBPs) are part of solute transport systems and serve to increase substrate affinity and uptake rates. In contrast to primary transport systems, the mechanism of SBP-dependent secondary transport is not well understood. Functional studies have thus far focused on Na+-coupled Tripartite ATP-independent periplasmic (TRAP) transporters for sialic acid. Herein, we report the in vitro functional characterization of TAXIPm-PQM from the human pathogen Proteus mirabilis. TAXIPm-PQM belongs to a TRAP-subfamily using a different type of SBP, designated TRAP-associated extracytoplasmic immunogenic (TAXI) protein. TAXIPm-PQM catalyzes proton-dependent α-ketoglutarate symport and its SBP is an essential component of the transport mechanism. Importantly, TAXIPm-PQM represents the first functionally characterized SBP-dependent secondary transporter that does not rely on a soluble SBP, but uses a membrane-anchored SBP instead.
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Affiliation(s)
- Anja Roden
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Melanie K Engelin
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Klaas M Pos
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany
| | - Eric R Geertsma
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt am Main, Germany.,Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, D-01307 Dresden, Germany
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5
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Payen S, Roy D, Boa A, Okura M, Auger JP, Segura M, Gottschalk M. Role of Maturation of Lipoproteins in the Pathogenesis of the Infection Caused by Streptococcus suis Serotype 2. Microorganisms 2021; 9:microorganisms9112386. [PMID: 34835511 PMCID: PMC8621357 DOI: 10.3390/microorganisms9112386] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/03/2021] [Accepted: 11/15/2021] [Indexed: 11/16/2022] Open
Abstract
Streptococcus suis serotype 2 is an important porcine bacterial pathogen associated with multiple pathologies in piglets. Bacterial lipoproteins (LPPs) have been described as playing important roles in the pathogenesis of the infection of other Gram-positive bacteria as adhesins, pro-inflammatory cell activators and/or virulence factors. In the current study, we aimed to evaluate the role of the prolipoprotein diacylglyceryl transferase (Lgt) and lipoprotein signal peptidase (Lsp) enzymes, which are responsible for LPP maturation, on the pathogenesis of the infection caused by two different sequence types (STs) of S. suis serotype 2 strains (virulent ST1 and highly virulent ST7). Through the use of isogenic Δlgt, Δlsp and double Δlgt/Δlsp mutants, it was shown that lack of these enzymes did not influence S. suis adhesion/invasion to porcine respiratory epithelial cells. However, in the absence of the Lsp and/or Lgt, a significant reduction in the capacity of S. suis to activate phagocytic cells and induce pro-inflammatory mediators (in vitro and in vivo) was observed. In general, results obtained with the double mutant did not differ in comparison to single mutants, indicating lack of an additive effect. Finally, our data suggest that these enzymes play a differential role in virulence, depending on the genetic background of the strain and being more important for the highly virulent ST7 strain.
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Affiliation(s)
- Servane Payen
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - David Roy
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Anaïs Boa
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Masatoshi Okura
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba 305-0856, Japan;
| | - Jean-Philippe Auger
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Mariela Segura
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
| | - Marcelo Gottschalk
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Research Group on Infectious Diseases in Production Animals (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC J2S 2M2, Canada; (S.P.); (D.R.); (A.B.); (J.-P.A.); (M.S.)
- Correspondence:
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6
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Bahr G, González LJ, Vila AJ. Metallo-β-lactamases in the Age of Multidrug Resistance: From Structure and Mechanism to Evolution, Dissemination, and Inhibitor Design. Chem Rev 2021; 121:7957-8094. [PMID: 34129337 PMCID: PMC9062786 DOI: 10.1021/acs.chemrev.1c00138] [Citation(s) in RCA: 96] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Antimicrobial resistance is one of the major problems in current practical medicine. The spread of genes coding for resistance determinants among bacteria challenges the use of approved antibiotics, narrowing the options for treatment. Resistance to carbapenems, last resort antibiotics, is a major concern. Metallo-β-lactamases (MBLs) hydrolyze carbapenems, penicillins, and cephalosporins, becoming central to this problem. These enzymes diverge with respect to serine-β-lactamases by exhibiting a different fold, active site, and catalytic features. Elucidating their catalytic mechanism has been a big challenge in the field that has limited the development of useful inhibitors. This review covers exhaustively the details of the active-site chemistries, the diversity of MBL alleles, the catalytic mechanism against different substrates, and how this information has helped developing inhibitors. We also discuss here different aspects critical to understand the success of MBLs in conferring resistance: the molecular determinants of their dissemination, their cell physiology, from the biogenesis to the processing involved in the transit to the periplasm, and the uptake of the Zn(II) ions upon metal starvation conditions, such as those encountered during an infection. In this regard, the chemical, biochemical and microbiological aspects provide an integrative view of the current knowledge of MBLs.
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Affiliation(s)
- Guillermo Bahr
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Lisandro J. González
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
| | - Alejandro J. Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda S/N, 2000 Rosario, Argentina
- Area Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
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7
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Pei X, Liu M, Zhou H, Fan H. Screening for phagocytosis resistance-related genes via a transposon mutant library of Streptococcus suis serotype 2. Virulence 2021; 11:825-838. [PMID: 32614642 PMCID: PMC7567436 DOI: 10.1080/21505594.2020.1782088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Streptococcus suis serotype 2 (SS2) is a serious zoonotic pathogen which causes symptoms of streptococcal toxic shock syndrome (STSS) and septicemia; these symptoms suggest that SS2 may have evade innate immunity. Phagocytosis is an important innate immunity process where phagocytosed pathogens are killed by lysosome enzymes, reactive oxygen, and nitrogen species, and acidic environments in macrophages following engulfment. A previously constructed mutant SS2 library was screened, revealing 13 mutant strains with decreased phagocytic resistance. Through inverse PCR, the transposon insertion sites were determined. Through bioinformatic analysis, the 13 disrupted genes were identified as Cps2F, 3 genes belonging to ABC transporters, WalR, TehB, rpiA, S-transferase encoding gene, prs, HsdM, GNAT family N-acetyltransferase encoding gene, proB, and upstream region of DnaK. Except for the capsular polysaccharide biosynthesis associated Cps2F, the other genes had not been linked to a role in anti-phagocytosis. The survival ability in macrophages and whole blood of randomly picked mutant strains were significantly impaired compared with wild-type ZY05719. The virulence of the mutant strains was also attenuated in a mouse infection model. In the WalR mutant, the transcription of HP1065 decreased significantly compared with wild-type strain, indicating WalR might regulated HP1065 expression and contribute to the anti-phagocytosis of SS2. In conclusion, we identified 13 genes that influenced the phagocytosis resistant ability of SS2, and many of these genes have not been reported to be associated with resistance to phagocytosis. Our work provides novel insight into resistance to phagocytosis, and furthers our understanding of the pathogenesis mechanism of SS2.
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Affiliation(s)
- Xiaomeng Pei
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China
| | - Mingxing Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China
| | - Hong Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University , Nanjing, China.,Jiangsu Co-innovation Center for the Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University , Yangzhou, China
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8
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Santos Junior MN, de Macêdo Neres NS, Campos GB, Bastos BL, Timenetsky J, Marques LM. A Review of Ureaplasma diversum: A Representative of the Mollicute Class Associated With Reproductive and Respiratory Disorders in Cattle. Front Vet Sci 2021; 8:572171. [PMID: 33681318 PMCID: PMC7930009 DOI: 10.3389/fvets.2021.572171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 01/13/2021] [Indexed: 12/22/2022] Open
Abstract
The Mollicutes class encompasses wall-less microbes with a reduced genome. They may infect plants, insects, humans, and animals including those on farms and in livestock. Ureaplasma diversum is a mollicute associated with decreased reproduction mainly in the conception rate in cattle, as well as weight loss and decreased quality in milk production. Therefore, U. diversum infection contributes to important economic losses, mainly in large cattle-producing countries such as the United States, China, Brazil, and India. The characteristics of Mollicutes, virulence, and pathogenic variations make it difficult to control their infections. Genomic analysis, prevalence studies, and immunomodulation assays help better understand the pathogenesis of bovine ureaplasma. Here we present the main features of transmission, virulence, immune response, and pathogenesis of U. diversum in bovines.
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Affiliation(s)
- Manoel Neres Santos Junior
- Department of Biointeraction, Multidisciplinary Institute of Health, Universidade Federal da Bahia, Vitória da Conquista, Brazil
- Department of Microbiology, State University of Santa Cruz (UESC), Ilhéus, Brazil
| | - Nayara Silva de Macêdo Neres
- Department of Biointeraction, Multidisciplinary Institute of Health, Universidade Federal da Bahia, Vitória da Conquista, Brazil
| | - Guilherme Barreto Campos
- Department of Biointeraction, Multidisciplinary Institute of Health, Universidade Federal da Bahia, Vitória da Conquista, Brazil
| | - Bruno Lopes Bastos
- Department of Biointeraction, Multidisciplinary Institute of Health, Universidade Federal da Bahia, Vitória da Conquista, Brazil
| | - Jorge Timenetsky
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Lucas Miranda Marques
- Department of Biointeraction, Multidisciplinary Institute of Health, Universidade Federal da Bahia, Vitória da Conquista, Brazil
- Department of Microbiology, State University of Santa Cruz (UESC), Ilhéus, Brazil
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
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9
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Ge X, Thorgersen MP, Poole FL, Deutschbauer AM, Chandonia JM, Novichkov PS, Gushgari-Doyle S, Lui LM, Nielsen T, Chakraborty R, Adams PD, Arkin AP, Hazen TC, Adams MWW. Characterization of a Metal-Resistant Bacillus Strain With a High Molybdate Affinity ModA From Contaminated Sediments at the Oak Ridge Reservation. Front Microbiol 2020; 11:587127. [PMID: 33193240 PMCID: PMC7604516 DOI: 10.3389/fmicb.2020.587127] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022] Open
Abstract
A nitrate- and metal-contaminated site at the Oak Ridge Reservation (ORR) was previously shown to contain the metal molybdenum (Mo) at picomolar concentrations. This potentially limits microbial nitrate reduction, as Mo is required by the enzyme nitrate reductase, which catalyzes the first step of nitrate removal. Enrichment for anaerobic nitrate-reducing microbes from contaminated sediment at the ORR yielded Bacillus strain EB106-08-02-XG196. This bacterium grows in the presence of multiple metals (Cd, Ni, Cu, Co, Mn, and U) but also exhibits better growth compared to control strains, including Pseudomonas fluorescens N2E2 isolated from a pristine ORR environment under low molybdate concentrations (<1 nM). Molybdate is taken up by the molybdate binding protein, ModA, of the molybdate ATP-binding cassette transporter. ModA of XG196 is phylogenetically distinct from those of other characterized ModA proteins. The genes encoding ModA from XG196, P. fluorescens N2E2 and Escherichia coli K12 were expressed in E. coli and the recombinant proteins were purified. Isothermal titration calorimetry analysis showed that XG196 ModA has a higher affinity for molybdate than other ModA proteins with a molybdate binding constant (KD) of 2.2 nM, about one order of magnitude lower than those of P. fluorescens N2E2 (27.0 nM) and E. coli K12 (25.0 nM). XG196 ModA also showed a fivefold higher affinity for molybdate than for tungstate (11 nM), whereas the ModA proteins from P. fluorescens N2E2 [KD (Mo) 27.0 nM, KD (W) 26.7 nM] and E. coli K12[(KD (Mo) 25.0 nM, KD (W) 23.8 nM] had similar affinities for the two oxyanions. We propose that high molybdate affinity coupled with resistance to multiple metals gives strain XG196 a competitive advantage in Mo-limited environments contaminated with high concentrations of metals and nitrate, as found at ORR.
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Affiliation(s)
- Xiaoxuan Ge
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Michael P Thorgersen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Farris L Poole
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - John-Marc Chandonia
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Pavel S Novichkov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Sara Gushgari-Doyle
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Lauren M Lui
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Torben Nielsen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Romy Chakraborty
- Earth and Environmental Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Paul D Adams
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Adam P Arkin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.,Department of Bioengineering, University of California, Berkeley, Berkeley, CA, United States
| | - Terry C Hazen
- Department of Civil and Environmental Engineering, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
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10
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Nguyen MT, Matsuo M, Niemann S, Herrmann M, Götz F. Lipoproteins in Gram-Positive Bacteria: Abundance, Function, Fitness. Front Microbiol 2020; 11:582582. [PMID: 33042100 PMCID: PMC7530257 DOI: 10.3389/fmicb.2020.582582] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
When one thinks of the Gram+ cell wall, the peptidoglycan (PG) scaffold in particular comes to mind. However, the cell wall also consists of many other components, for example those that are covalently linked to the PG: the wall teichoic acid and the cell wall proteins tethered by the sortase. In addition, there are completely different molecules that are anchored in the cytoplasmic membrane and span the cell wall. These are lipoteichoic acids and bacterial lipoproteins (Lpp). The latter are in the focus of this review. Lpp are present in almost all bacteria. They fulfill a wealth of different tasks. They represent the window to the outside world by recognizing nutrients and incorporating them into the bacterial cell via special transport systems. Furthermore, they perform very diverse and special tasks such as acting as chaperonin, as cyclomodulin, contributing to invasion of host cells or uptake of plasmids via conjugation. All these functions are taken over by the protein part. Nevertheless, the lipid part of the Lpp plays an as important role as the protein part. It is the released lipoproteins and derived lipopeptides that massively modulate our immune system and ultimately play an important role in immune tolerance or non-tolerance. All these varied activities of the Lpp are considered in this review article.
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Affiliation(s)
- Minh-Thu Nguyen
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Miki Matsuo
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Silke Niemann
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Mathias Herrmann
- Section of Medical and Geographical Infectiology, Institute of Medical Microbiology, University Hospital of Münster, Münster, Germany
| | - Friedrich Götz
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen (IMIT), Microbial Genetics, University of Tübingen, Tübingen, Germany
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11
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NisI Maturation and Its Influence on Nisin Resistance in Lactococcus lactis. Appl Environ Microbiol 2020; 86:AEM.01306-20. [PMID: 32709730 DOI: 10.1128/aem.01306-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/22/2020] [Indexed: 02/02/2023] Open
Abstract
NisI confers immunity against nisin, with high substrate specificity to prevent a suicidal effect in nisin-producing Lactococcus lactis strains. However, the NisI maturation process as well as its influence on nisin resistance has not been characterized. Here, we report the roles of lipoprotein signal peptidase II (Lsp) and prolipoprotein diacylglyceryl transferase (Lgt) in NisI maturation and nisin resistance of L. lactis F44. We found that the resistance of nisin of an Lsp-deficient mutant remarkably decreased, while no significant differences in growth were observed. We demonstrated that Lsp could cleave signal peptide of NisI precursor in vitro Moreover, diacylglyceryl modification of NisI catalyzed by Lgt played a decisive role in attachment of NisI on the cell envelope, while it exhibited no effects on cleavage of the signal peptides of NisI precursor. The dissociation constant (KD ) for the interaction between nisin and NisI exhibited a 2.8-fold increase compared with that between nisin and pre-NisI with signal peptide by surface plasmon resonance (SPR) analysis, providing evidence that Lsp-catalyzed signal peptide cleavage was critical for the immune activity of NisI. Our study revealed the process of NisI maturation in L. lactis and presented a potential strategy to enhance industrial nisin production.IMPORTANCE Nisin, a safe and natural antimicrobial peptide, has a long and impressive history as a food preservative and is also considered a novel candidate to alleviate the increasingly serious threat of antibiotic resistance. Nisin is produced by certain L. lactis strains. The nisin immunity protein NisI, a membrane-bound lipoprotein, is expressed by nisin producers to avoid suicidal action. Here, we report the roles of Lsp and Lgt in NisI maturation and nisin resistance of L. lactis F44. The results verified the importance of Lsp to NisI-conferred immunity and Lgt to localization. Our study revealed the process of NisI maturation in L. lactis and presented a potential strategy to enhance industrial nisin production.
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Kapil S, Sharma V. d-Amino acids in antimicrobial peptides: a potential approach to treat and combat antimicrobial resistance. Can J Microbiol 2020; 67:119-137. [PMID: 32783775 DOI: 10.1139/cjm-2020-0142] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Antimicrobial resistance is one of the leading challenges in the human healthcare segment. Advances in antimicrobial resistance have triggered exploration of natural alternatives to stabilize its seriousness. Antimicrobial peptides are small, positively charged oligopeptides that are as potent as commercially available antibiotics against a wide spectrum of organisms, such as Gram-positive bacteria, Gram-negative bacteria, viruses, and fungal strains. In addition to their antibiotic capabilities, these peptides possess anticancer activity, activate the immune response, and regulate inflammation. Peptides have distinct modes of action and fall into various categories due to their amino acid composition. Although antimicrobial peptides specifically target the bacterial cytoplasmic membrane, they can also target the cell nucleus and protein synthesis. Owing to the increasing demand for novel treatments against the threat of antimicrobial resistance, naturally synthesized peptides are a beneficial development concept. Antimicrobial peptides are pervasive and can easily be modified using de-novo synthesis technology. Antimicrobial peptides can be isolated from natural resources such as humans, plants, bacteria, and fungi. This review gives a brief overview of antimicrobial peptides and their diastereomeric composition. Other current trends, the future scope of antimicrobial peptides, and the role of d-amino acids are also discussed, with a specific emphasis on the design and development of new drugs.
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Affiliation(s)
- Shikha Kapil
- University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India.,University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India
| | - Vipasha Sharma
- University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India.,University Institute of Biotechnology, Chandigarh University, Gharuan Mohali, Punjab 140413, India
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13
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McClain MS, Voss BJ, Cover TL. Lipoprotein Processing and Sorting in Helicobacter pylori. mBio 2020; 11:e00911-20. [PMID: 32430470 PMCID: PMC7240156 DOI: 10.1128/mbio.00911-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Our current understanding of lipoprotein synthesis and localization in Gram-negative bacteria is based primarily on studies of Escherichia coli Newly synthesized E. coli prolipoproteins undergo posttranslational modifications catalyzed by three essential enzymes (Lgt, LspA, and Lnt). The mature lipoproteins are then sorted to the inner or outer membrane via the Lol system (LolABCDE). Recent studies suggested that this paradigm may not be universally applicable among different classes of proteobacteria. In this study, we conducted a systematic analysis of lipoprotein processing and sorting in Helicobacter pylori, a member of the Epsilonproteobacteria that colonizes the human stomach. We show that H. pylorilgt, lspA, and lnt homologs can complement conditionally lethal E. coli mutant strains in which expression of these genes is conditionally regulated. Mutagenesis studies and analyses of conditionally lethal H. pylori mutant strains indicate that lgt and lspA are essential for H. pylori growth but lnt is dispensable. H. pylorilolA and the single lolC (or lolE) homolog are also essential genes. We then explored the role of lipoproteins in H. pylori Cag type IV secretion system (Cag T4SS) activity. Comparative analysis of the putative VirB7 homolog CagT in wild-type and lnt mutant H. pylori strains indicates that CagT undergoes amino-terminal modifications consistent with lipidation, and we show that CagT lipidation is essential for CagT stability and Cag T4SS function. This work demonstrates that lipoprotein synthesis and localization in H. pylori diverge from the canonical pathways and that lipidation of a T4SS component is necessary for H. pylori Cag T4SS activity.IMPORTANCE Bacterial lipoproteins have diverse roles in multiple aspects of bacterial physiology, antimicrobial resistance, and pathogenesis. Dedicated pathways direct the posttranslational lipidation and localization of lipoproteins, but there is considerable variation in these pathways among the proteobacteria. In this study, we characterized the proteins responsible for lipoprotein synthesis and localization in Helicobacter pylori, a member of the Epsilonproteobacteria that contributes to stomach cancer pathogenesis. We also provide evidence suggesting that lipidation of CagT, a component of the H. pylori Cag T4SS, is required for delivery of the H. pylori CagA oncoprotein into human gastric cells. Overall, these results constitute the first systematic analysis of H. pylori lipoprotein production and localization pathways and reveal how these processes in H. pylori differ from corresponding pathways in model proteobacteria.
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Affiliation(s)
- Mark S McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Bradley J Voss
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Timothy L Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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14
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Ploplis VA, Castellino FJ. Host Pathways of Hemostasis that Regulate Group A Streptococcus pyogenes Pathogenicity. Curr Drug Targets 2020; 21:193-201. [PMID: 31556853 PMCID: PMC7670306 DOI: 10.2174/1389450120666190926152914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/02/2019] [Accepted: 09/06/2019] [Indexed: 11/22/2022]
Abstract
A hallmark feature of severe Group A Streptococcus pyogenes (GAS) infection is dysregulated hemostasis. Hemostasis is the primary pathway for regulating blood flow through events that contribute towards clot formation and its dissolution. However, a number of studies have identified components of hemostasis in regulating survival and dissemination of GAS. Several proteins have been identified on the surface of GAS and they serve to either facilitate invasion to host distal sites or regulate inflammatory responses to the pathogen. GAS M-protein, a surface-exposed virulence factor, appears to be a major target for interactions with host hemostasis proteins. These interactions mediate biochemical events both on the surface of GAS and in the solution when M-protein is released into the surrounding environment through shedding or regulated proteolytic processes that dictate the fate of this pathogen. A thorough understanding of the mechanisms associated with these interactions could lead to novel approaches for altering the course of GAS pathogenicity.
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Affiliation(s)
- Victoria A. Ploplis
- University of Notre Dame, W.M. Keck Center for Transgene Research, 230 Raclin-Carmichael Hall, Notre Dame, IN 46556 USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
| | - Francis J. Castellino
- University of Notre Dame, W.M. Keck Center for Transgene Research, 230 Raclin-Carmichael Hall, Notre Dame, IN 46556 USA
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, USA
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15
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Abstract
Diatoms can access inorganic iron with remarkable efficiency, but this process is contingent on carbonate ion concentration. As ocean acidification reduces carbonate concentration, inorganic iron uptake may be discouraged in favor of carbonate-independent uptake. We report details of an iron assimilation process that needs no carbonate but requires exogenous compounds produced by cooccurring organisms. We show this process to be critical for diatom growth at high siderophore concentrations, but ineffective at acquiring iron from low-affinity organic chelators or lithogenic particulates. Understanding the caveats associated with iron source preference in diatoms will help predict the impacts of climate change on microbial community structure in high-nitrate low-chlorophyll ecosystems. Iron uptake by diatoms is a biochemical process with global biogeochemical implications. In large regions of the surface ocean diatoms are both responsible for the majority of primary production and frequently experiencing iron limitation of growth. The strategies used by these phytoplankton to extract iron from seawater constrain carbon flux into higher trophic levels and sequestration into sediments. In this study we use reverse genetic techniques to target putative iron-acquisition genes in the model pennate diatom Phaeodactylum tricornutum. We describe components of a reduction-dependent siderophore acquisition pathway that relies on a bacterial-derived receptor protein and provides a viable alternative to inorganic iron uptake under certain conditions. This form of iron uptake entails a close association between diatoms and siderophore-producing organisms during low-iron conditions. Homologs of these proteins are found distributed across diatom lineages, suggesting the significance of siderophore utilization by diatoms in the marine environment. Evaluation of specific proteins enables us to confirm independent iron-acquisition pathways in diatoms and characterize their preferred substrates. These findings refine our mechanistic understanding of the multiple iron-uptake systems used by diatoms and help us better predict the influence of iron speciation on taxa-specific iron bioavailability.
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16
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Evidence to Suggest Bacterial Lipoprotein Diacylglyceryl Transferase (Lgt) is a Weakly Associated Inner Membrane Protein. J Membr Biol 2019; 252:563-575. [DOI: 10.1007/s00232-019-00076-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 10/26/2022]
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17
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Copper-Induced Expression of a Transmissible Lipoprotein Intramolecular Transacylase Alters Lipoprotein Acylation and the Toll-Like Receptor 2 Response to Listeria monocytogenes. J Bacteriol 2019; 201:JB.00195-19. [PMID: 30988036 DOI: 10.1128/jb.00195-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 04/08/2019] [Indexed: 12/30/2022] Open
Abstract
Bacterial lipoproteins are globular proteins anchored to the extracytoplasmic surfaces of cell membranes through lipidation at a conserved N-terminal cysteine. Lipoproteins contribute to an array of important cellular functions for bacteria, as well as being a focal point for innate immune system recognition through binding to Toll-like receptor 2 (TLR2) heterodimer complexes. Although lipoproteins are conserved among nearly all classes of bacteria, the presence and type of α-amino-linked acyl chain are highly variable and even strain specific within a given bacterial species. The reason for lyso-lipoprotein formation and N-acylation variability in general is presently not fully understood. In Enterococcus faecalis, lipoproteins are anchored by an N-acyl-S-monoacyl-glyceryl cysteine (lyso form) moiety installed by a chromosomally encoded lipoprotein intramolecular transacylase (Lit). Here, we describe a mobile genetic element common to environmental isolates of Listeria monocytogenes and Enterococcus spp. encoding a functional Lit ortholog (Lit2) that is cotranscribed with several well-established copper resistance determinants. Expression of Lit2 is tightly regulated, and induction by copper converts lipoproteins from the diacylglycerol-modified form characteristic of L. monocytogenes type strains to the α-amino-modified lyso form observed in E. faecalis Conversion to the lyso form through either copper addition to media or constitutive expression of lit2 decreases TLR2 recognition when using an activated NF-κB secreted embryonic alkaline phosphatase reporter assay. While lyso formation significantly diminishes TLR2 recognition, lyso-modified lipoprotein is still predominantly recognized by the TLR2/TLR6 heterodimer.IMPORTANCE The induction of lipoprotein N-terminal remodeling in response to environmental copper in Gram-positive bacteria suggests a more general role in bacterial cell envelope physiology. N-terminal modification by lyso formation, in particular, simultaneously modulates the TLR2 response in direct comparison to their diacylglycerol-modified precursors. Thus, use of copper as a frontline antimicrobial control agent and ensuing selection raises the potential of diminished innate immune sensing and enhanced bacterial virulence.
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18
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Chen Y, Xiao JN, Li Y, Xiao YJ, Xiong YQ, Liu Y, Wang SJ, Ji P, Zhao GP, Shen H, Lu SH, Fan XY, Wang Y. Mycobacterial Lipoprotein Z Triggers Efficient Innate and Adaptive Immunity for Protection Against Mycobacterium tuberculosis Infection. Front Immunol 2019; 9:3190. [PMID: 30700988 PMCID: PMC6343430 DOI: 10.3389/fimmu.2018.03190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 12/31/2018] [Indexed: 12/28/2022] Open
Abstract
Mycobacterial lipoproteins are considered to be involved in both virulence and immunoregulatory processes during Mycobacterium tuberculosis (M.tb) infection. In our previous investigations on the immunoreactivity of more than 30 M.tb proteins in active TB patients, we identified mycobacterial lipoprotein Z (LppZ) as one of the most immune dominant antigens. How LppZ triggers immune responses is still unclear. In this study, we analyzed LppZ-mediated innate and adaptive immunity using a murine air pouch model and an M.tb infection model, respectively. We found that LppZ could not only recruit inflammatory cells but also induce the production of proinflammatory cytokines inside the pouches. LppZ could also induce strong Th1 responses following immunization and confer protection against challenge with M.tb virulent strain H37Rv at a similar level to BCG vaccination but with less pathological damage in the lungs. Furthermore, we revealed the presence of LppZ-specific functional CD4+ T cells in the lungs of the challenged mice that were capable of secreting double or triple cytokines, including IFN-γ, IL-2, and TNF-α. Our study thus demonstrates that LppZ is of strong immunogenicity during M.tb infection in both humans and mice and has the ability to trigger effective innate and cellular immunity. Considering the limitations of candidate antigens in the pipeline of TB vaccine development, LppZ-mediated immune protection against M.tb challenge in the mouse model implies its potential application in vaccine development.
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Affiliation(s)
- Yingying Chen
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China
| | - Jia-Ni Xiao
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China
| | - Yong Li
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China
| | - Yang-Jiong Xiao
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China
| | - Yan-Qing Xiong
- Key Laboratory of Medical Molecular Virology of MOE/MOH, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Ying Liu
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China
| | - Shu-Jun Wang
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China
| | - Ping Ji
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China
| | - Guo-Ping Zhao
- Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China
| | - Hao Shen
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China.,Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Shui-Hua Lu
- Key Laboratory of Medical Molecular Virology of MOE/MOH, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Xiao-Yong Fan
- Key Laboratory of Medical Molecular Virology of MOE/MOH, Shanghai Public Health Clinical Center, Fudan University, Shanghai, China.,TB Center, Shanghai Emerging and Re-emerging Infectious Disease Institute, Fudan University, Shanghai, China
| | - Ying Wang
- Department of Microbiology and Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai Institute of Immunology, Shanghai, China.,Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China
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19
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Licht A, Bommer M, Werther T, Neumann K, Hobe C, Schneider E. Structural and functional characterization of a maltose/maltodextrin ABC transporter comprising a single solute binding domain (MalE) fused to the transmembrane subunit MalF. Res Microbiol 2019; 170:1-12. [DOI: 10.1016/j.resmic.2018.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 08/15/2018] [Accepted: 08/28/2018] [Indexed: 01/21/2023]
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20
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Evidence from Mutational Analysis for a Single Transmembrane Substrate Binding Site in the Histidine ATP-Binding Cassette Transporter of Salmonella enterica Serovar Typhimurium. J Bacteriol 2018; 201:JB.00521-18. [PMID: 30348830 DOI: 10.1128/jb.00521-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 10/14/2018] [Indexed: 11/20/2022] Open
Abstract
The histidine ATP-binding cassette (ABC) transporter of Salmonella enterica serovar Typhimurium is among the best-studied type I ABC import systems. The transporter consists of two transmembrane subunits, HisQ and HisM, and a homodimer of the nucleotide-binding subunit, HisP. Substrates are delivered by two periplasmic solute binding proteins, HisJ and LAO, with preferences for histidine and for lysine, arginine, and ornithine, respectively. A homology model was built by using the arginine-bound crystal structure of the closely related Art(QN)2 transporter of Thermoanaerobacter tengcongensis as the template. In the homodimeric Art(QN)2, one substrate molecule is bound to each of the ArtQ subunits, whereas the structural model and sequence alignments predict only one substrate molecule in contact with HisM. To address the question whether one or two binding sites exist in heterodimeric HisQM, we have studied the functional consequences of mutations by monitoring (i) the complementation of growth on d-histidine of auxotrophic tester strains, (ii) the growth of tester strains on arginine as a nitrogen source, and (iii) ATPase activity of purified variants in a lipid environment. Our results demonstrate that two negatively charged residues, namely, HisM-E166 and HisQ-D61, are indispensable for function. Furthermore, the complete reconstruction of an ArtQ-like binding site in HisQ resulted in an inactive transporter. Likewise, switching the positions of both negatively charged residues between HisQ and HisM caused transport-deficient phenotypes. Thus, we propose that one substrate molecule is primarily liganded by residues of HisM while HisQ-D61 forms a crucial salt bridge with the α-amino group of the substrate.IMPORTANCE Canonical ATP-binding cassette (ABC) importers are major players in the translocation of numerous nutrients, vitamins, and growth factors to the cytoplasm of prokaryotes. Moreover, some ABC importers have been identified as virulence factors in bacterial pathogenesis. Thus, a full understanding of their mode of action is considered a prerequisite, among others, for the development of novel antibacterial drugs. However, mainly owing to the lack of structural information, the knowledge of the chemical nature and number of substrate binding sites formed by the transmembrane subunits of ABC importers is scarce. Here, we provide evidence from mutational analyses that, in contrast to homologous homodimeric systems, the heterodimeric histidine transporter of Salmonella enterica serovar Typhimurium is liganding only one substrate molecule between its transmembrane subunits, HisM and HisQ.
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21
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Xia Z, Lei L, Zhang HY, Wei HL. Characterization of the ModABC Molybdate Transport System of Pseudomonas putida in Nicotine Degradation. Front Microbiol 2018; 9:3030. [PMID: 30627117 PMCID: PMC6295455 DOI: 10.3389/fmicb.2018.03030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/23/2018] [Indexed: 01/09/2023] Open
Abstract
Pseudomonas putida J5 is an efficient nicotine-degrading bacterial strain that catabolizes nicotine through the pyrrolidine pathway. In our previous study, we used Tn5 transposon mutagenesis to investigate nicotine metabolism-associated genes, and 18 nicotine degradation-deficient mutants were isolated from 16,324 Tn5-transformants. Three of the mutants were Tn5 inserts into the modABC gene cluster that encoded an ABC-type, high-affinity, molybdate transporter. In-frame deletion of the modABC genes abolished the nicotine-degrading ability of strain J5, and complementation with modABC either from P. putida or Arthrobacter oxidans restored the degrading activity of the mutant to wild-type level. Nicotine degradation of J5 was inhibited markedly by addition of tungstate, a specific antagonist of molybdate. Molybdate at a non-physiologically high concentration (100 μM) fully restored nicotine-degrading activity and recovered growth of the modABC mutant in a nicotine minimal medium. Transcriptional analysis revealed that the expression of modABC was up-regulated at low molybdate concentrations and down-regulated at high moybdate concentrations, which indicated that at least one other system was able to transport molybdate, but with lower affinity. These results suggested that the molybdate transport system was essential to nicotine metabolism in P. putida J5.
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Affiliation(s)
- Zhenyuan Xia
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.,Yunnan Academy of Tobacco Agricultural Science, Kunming, China
| | - Liping Lei
- Yunnan Academy of Tobacco Agricultural Science, Kunming, China
| | - Hong-Yue Zhang
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hai-Lei Wei
- Key Laboratory of Microbial Resources Collection and Preservation, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China
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22
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Kitamura S, Wolan DW. Probing substrate recognition of bacterial lipoprotein signal peptidase using FRET reporters. FEBS Lett 2018; 592:2289-2296. [DOI: 10.1002/1873-3468.13155] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 05/10/2018] [Accepted: 05/30/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Seiya Kitamura
- Department of Molecular Medicine; The Scripps Research Institute; La Jolla CA USA
- Department of Integrative Structural and Computational Biology; The Scripps Research Institute; La Jolla CA USA
| | - Dennis W. Wolan
- Department of Molecular Medicine; The Scripps Research Institute; La Jolla CA USA
- Department of Integrative Structural and Computational Biology; The Scripps Research Institute; La Jolla CA USA
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The aggregation-promoting factor in Lactobacillus delbrueckii ssp. bulgaricus: confirmation of the presence and expression of the apf gene and in silico analysis of the corresponding protein. World J Microbiol Biotechnol 2018; 34:97. [PMID: 29923077 DOI: 10.1007/s11274-018-2480-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Abstract
In lactobacilli the aggregation phenotype is linked to their ability to colonize the intestinal and urogenital tracts and to counteract pathogenic bacteria. In all available complete genome sequences of Lactobacillus delbrueckii ssp. bulgaricus there are at least two genes putatively related to aggregation, one of which is annotated as aggregation-promoting factor (apf). Here we report the results from the in silico analysis of this gene and its product. The apf gene was present in the genome of all 70 tested L. delbr. ssp. bulgaricus strains. Its expression was confirmed for a selection of five strains with aggregation phenotype and two aggregation-negative strains. The mature Apf protein had a length of 257-284 amino acids with predicted molecular weight in the range of 28.64-30.36 kDa and isoelectric point of 10.6 ± 0.1, showing some similarity to Apf1 and Apf2 from L. johnsonii NCC533 and Apf1 and Apf2 from L. gasseri which are similar in size (28-35 kDa) and share a similar high isoelectric point (pI > 9). Predictive analyzes have indicated that Apf is a secretory protein. The 30 amino acid signal peptide and the predicted cleavage site in the pre-protein suggested that it was processed by Type I Signal protease. In the mature Apf protein a glutamine-rich N-terminal region was followed by an unusual lysine/alanine-rich region with variable length, supposed to be positively charged under physiological conditions, interacting with bacterial teichoic acids. The alignment of the C-termini of the Apf proteins showed similarity to conserved C-terminal domains in aggregation-related proteins in other lactobacilli such as Apf1 of Lactobacillus johnsonii ATCC 11506 and the secretory protein Sep of L. fermentum BR11, that may be involved in non-covalent binding to carbohydrates. The C-terminal anchor and the cationic domain in Apf may serve as mediators of physical cell-to-cell interaction in L. delbr. ssp. bulgaricus.
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One Intact Transmembrane Substrate Binding Site Is Sufficient for the Function of the Homodimeric Type I ATP-Binding Cassette Importer for Positively Charged Amino Acids Art(MP) 2 of Geobacillus stearothermophilus. J Bacteriol 2018; 200:JB.00092-18. [PMID: 29581409 DOI: 10.1128/jb.00092-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/20/2018] [Indexed: 02/04/2023] Open
Abstract
ATP-binding cassette (ABC) transport systems comprise two transmembrane domains/subunits that form a translocation path and two nucleotide-binding domains/subunits that bind and hydrolyze ATP. Prokaryotic canonical ABC import systems require an extracellular substrate-binding protein for function. Knowledge of substrate-binding sites within the transmembrane subunits is scarce. Recent crystal structures of the ABC importer Art(QN)2 for positively charged amino acids of Thermoanerobacter tengcongensis revealed the presence of one substrate molecule in a defined binding pocket in each of the transmembrane subunits, ArtQ (J. Yu, J. Ge, J. Heuveling, E. Schneider, and M. Yang, Proc Natl Acad Sci U S A 112:5243-5248, 2015, https://doi.org/10.1073/pnas.1415037112). This finding raised the question of whether both sites must be loaded with substrate prior to initiation of the transport cycle. To address this matter, we first explored the role of key residues that form the binding pocket in the closely related Art(MP)2 transporter of Geobacillus stearothermophilus, by monitoring consequences of mutations in ArtM on ATPase and transport activity at the level of purified proteins embedded in liposomes. Our results emphasize that two negatively charged residues (E153 and D160) are crucial for wild-type function. Furthermore, the variant Art[M(L67D)P]2 exhibited strongly impaired activities, which is why it was considered for construction of a hybrid complex containing one intact and one impaired substrate-binding site. Activity assays clearly revealed that one intact binding site was sufficient for function. To our knowledge, our study provides the first biochemical evidence on transmembrane substrate-binding sites of an ABC importer.IMPORTANCE Canonical prokaryotic ATP-binding cassette importers mediate the uptake of a large variety of chemicals, including nutrients, osmoprotectants, growth factors, and trace elements. Some also play a role in bacterial pathogenesis, which is why full understanding of their mode of action is of the utmost importance. One of the unsolved problems refers to the chemical nature and number of substrate binding sites formed by the transmembrane subunits. Here, we report that a hybrid amino acid transporter of G. stearothermophilus, encompassing one intact and one impaired transmembrane binding site, is fully competent in transport, suggesting that the binding of one substrate molecule is sufficient to trigger the translocation process.
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Kitamura S, Owensby A, Wall D, Wolan DW. Lipoprotein Signal Peptidase Inhibitors with Antibiotic Properties Identified through Design of a Robust In Vitro HT Platform. Cell Chem Biol 2018; 25:301-308.e12. [PMID: 29337186 DOI: 10.1016/j.chembiol.2017.12.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 11/09/2017] [Accepted: 12/19/2017] [Indexed: 11/29/2022]
Abstract
As resistance to antibiotics increases, the exploration of new targets and strategies to combat pathogenic bacteria becomes more urgent. Ideal protein targets are required for viability across many species, are unique to prokaryotes to limit effects on the host, and have robust assays to quantitate activity and identify inhibitors. Lipoprotein signal peptidase (Lsp) is a transmembrane aspartyl protease required for lipoprotein maturation and comprehensively fits these criteria. Here, we have developed the first in vitro high-throughput assay to monitor proteolysis by Lsp. We employed our high-throughput screen assay against 646,275 compounds to discover inhibitors of Lsp and synthesized a range of analogs to generate molecules with nanomolar half maximal inhibitory concentration values. Importantly, our inhibitors are effective in preventing the growth of E. coli cultures in the presence of outer-membrane permeabilizer PMBN and should facilitate development of antibacterial agents with a novel mechanism of action to treat antibiotic-resistant bacteria.
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Affiliation(s)
- Seiya Kitamura
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Anna Owensby
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Daniel Wall
- Department of Molecular Biology, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071, USA
| | - Dennis W Wolan
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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Stringency of bacterial prolipoprotein signal peptidase (LspA) in recognition of signal peptides - Structure-function correlation. Biochem Biophys Res Commun 2017; 488:413-417. [PMID: 28506828 DOI: 10.1016/j.bbrc.2017.05.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/11/2017] [Indexed: 11/22/2022]
Abstract
Bacterial lipid modification of proteins is an essential post-translational event committed by Phosphatidylglycerol: prolipoprotein diacylglyceryl transferase (Lgt) by catalysing diacyglyceryl transfer from Phosphatidylglycerol to cysteine present in the characteristic 'lipobox' ([LVI] (-3) [ASTVI] (-2) [GAS] (-1) C (+1)) of prolipoprotein signal peptides. This is then followed by the cleavage of the signal peptide by lipoprotein-specific signal peptidase (LspA). It had been known for long that threonine at the -1 position allows diacylglyceryl modification by Lgt, but not signal peptide cleavage by LspA. We have addressed this unexplained stringency by computational analysis of the recently published 3D structure of LspA with its competitive inhibitor as well as transition state analogue, globomycin using PyMoL viewing tool and VADAR (Volume, Area, Dihedral Angle Reporter) web server. The propensity to form hydrogen bond (2.9a) between the hydroxyl group of threonine (not possible with serine) and the NH of the lipid-modified cysteine, possible only in the transition state, will prevent the protonation of NH of the leaving peptide and therefore its cleavage. This knowledge could be useful for designing inhibitors of this essential pathway in bacteria or for engineering LspA.
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Homburg C, Bommer M, Wuttge S, Hobe C, Beck S, Dobbek H, Deutscher J, Licht A, Schneider E. Inducer exclusion in Firmicutes: insights into the regulation of a carbohydrate ATP binding cassette transporter from Lactobacillus casei BL23 by the signal transducing protein P-Ser46-HPr. Mol Microbiol 2017; 105:25-45. [PMID: 28370477 DOI: 10.1111/mmi.13680] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2017] [Indexed: 12/24/2022]
Abstract
Catabolite repression is a mechanism that enables bacteria to control carbon utilization. As part of this global regulatory network, components of the phosphoenolpyruvate:carbohydrate phosphotransferase system inhibit the uptake of less favorable sugars when a preferred carbon source such as glucose is available. This process is termed inducer exclusion. In bacteria belonging to the phylum Firmicutes, HPr, phosphorylated at serine 46 (P-Ser46-HPr) is the key player but its mode of action is elusive. To address this question at the level of purified protein components, we have chosen a homolog of the Escherichia coli maltose/maltodextrin ATP-binding cassette transporter from Lactobacillus casei (MalE1-MalF1G1K12 ) as a model system. We show that the solute binding protein, MalE1, binds linear and cyclic maltodextrins but not maltose. Crystal structures of MalE1 complexed with these sugars provide a clue why maltose is not a substrate. P-Ser46-HPr inhibited MalE1/maltotetraose-stimulated ATPase activity of the transporter incorporated in proteoliposomes. Furthermore, cross-linking experiments revealed that P-Ser46-HPr contacts the nucleotide-binding subunit, MalK1, in proximity to the Walker A motif. However, P-Ser46-HPr did not block binding of ATP to MalK1. Together, our findings provide first biochemical evidence that P-Ser-HPr arrests the transport cycle by preventing ATP hydrolysis at the MalK1 subunits of the transporter.
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Affiliation(s)
- Constanze Homburg
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Martin Bommer
- Institut für Biologie/Strukturbiologie und Biochemie, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Steven Wuttge
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Carolin Hobe
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Sebastian Beck
- Institut für Chemie/Angewandte Analytik und Umweltchemie, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Holger Dobbek
- Institut für Biologie/Strukturbiologie und Biochemie, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Josef Deutscher
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, F-78350, France.,Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, Centre National de la Recherche Scientifique, UMR8261, Paris, F-75005, France
| | - Anke Licht
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
| | - Erwin Schneider
- Institut für Biologie/Physiologie der Mikroorganismen, Humboldt-Universität zu Berlin, Berlin, D-10099, Germany
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Narita SI, Tokuda H. Bacterial lipoproteins; biogenesis, sorting and quality control. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:1414-1423. [PMID: 27871940 DOI: 10.1016/j.bbalip.2016.11.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 11/11/2016] [Accepted: 11/14/2016] [Indexed: 12/20/2022]
Abstract
Bacterial lipoproteins are a subset of membrane proteins localized on either leaflet of the lipid bilayer. These proteins are anchored to membranes through their N-terminal lipid moiety attached to a conserved Cys. Since the protein moiety of most lipoproteins is hydrophilic, they are expected to play various roles in a hydrophilic environment outside the cytoplasmic membrane. Gram-negative bacteria such as Escherichia coli possess an outer membrane, to which most lipoproteins are sorted. The Lol pathway plays a central role in the sorting of lipoproteins to the outer membrane after lipoprotein precursors are processed to mature forms in the cytoplasmic membrane. Most lipoproteins are anchored to the inner leaflet of the outer membrane with their protein moiety in the periplasm. However, recent studies indicated that some lipoproteins further undergo topology change in the outer membrane, and play critical roles in the biogenesis and quality control of the outer membrane. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop.
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Affiliation(s)
| | - Hajime Tokuda
- University of Morioka, Takizawa, Iwate 020-0694, Japan.
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Kubicek-Sutherland JZ, Lofton H, Vestergaard M, Hjort K, Ingmer H, Andersson DI. Antimicrobial peptide exposure selects for Staphylococcus aureus resistance to human defence peptides. J Antimicrob Chemother 2016; 72:115-127. [PMID: 27650186 PMCID: PMC5161045 DOI: 10.1093/jac/dkw381] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 07/29/2016] [Accepted: 08/12/2016] [Indexed: 02/06/2023] Open
Abstract
Background The clinical development of antimicrobial peptides (AMPs) is currently under evaluation to combat the rapid increase in MDR bacterial pathogens. However, many AMPs closely resemble components of the human innate immune system and the ramifications of prolonged bacterial exposure to AMPs are not fully understood. Objectives We show that in vitro serial passage of a clinical USA300 MRSA strain in a host-mimicking environment containing host-derived AMPs results in the selection of stable AMP resistance. Methods Serial passage experiments were conducted using steadily increasing concentrations of LL-37, PR-39 or wheat germ histones. WGS and proteomic analysis by MS were used to identify the molecular mechanism associated with increased tolerance of AMPs. AMP-resistant mutants were characterized by measuring in vitro fitness, AMP and antibiotic susceptibility, and virulence in a mouse model of sepsis. Results AMP-resistant Staphylococcus aureus mutants often displayed little to no fitness cost and caused invasive disease in mice. Further, this phenotype coincided with diminished susceptibility to both clinically prescribed antibiotics and human defence peptides. Conclusions These findings suggest that therapeutic use of AMPs could select for virulent mutants with cross-resistance to human innate immunity as well as antibiotic therapy. Thus, therapeutic use of AMPs and the implications of cross-resistance need to be carefully monitored and evaluated.
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Affiliation(s)
| | - Hava Lofton
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123, Uppsala, Sweden
| | - Martin Vestergaard
- Department of Veterinary Disease Biology, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Copenhagen, Denmark
| | - Karin Hjort
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123, Uppsala, Sweden
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, University of Copenhagen, Stigbøjlen 4, 1870 Frederiksberg C, Copenhagen, Denmark
| | - Dan I Andersson
- Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, 75123, Uppsala, Sweden
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Proteomics Analyses and Morphological Structure of Bacillus subtilis Inactivated by Pulsed Magnetic Field. FOOD BIOPHYS 2016. [DOI: 10.1007/s11483-016-9444-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Panicker IS, Kanci A, Markham PF, Browning GF. Effect of differing +2 amino acids on export of a heterologous PhoA lipoprotein in Mycoplasma gallisepticum. MICROBIOLOGY-SGM 2016; 162:1300-1309. [PMID: 27329526 DOI: 10.1099/mic.0.000327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The significance of the amino acid adjacent to the amino terminal cysteine of lipoproteins, the +2 amino acid, has been well documented in E. coli and there have also been limited studies on Gram-positive bacteria. In this study we investigated whether there was any preference for specific residues and any targeting role attributable to different residues following the cysteine at the amino terminus in lipoproteins of Mycoplasma gallisepticum. There were found to be distinct preferences in this position that vary considerably from the preferences seen in Gram-positive and Gram-negative bacteria. The effect of different amino acids at the +2 position was studied using the pTAP vector, which has been shown to express PhoA as a lipoprotein. Replacement of the threonine at the +2 position in the PhoA lipoprotein with hydrophobic amino acids resulted in higher levels of expression of alkaline phosphatase, while replacement with hydrophilic amino acids resulted in lower levels of expression of alkaline phosphatase. Changes in the +2 amino acid did not appear to alter export of the PhoA lipoprotein to the membrane fraction, but a difference was seen in susceptibility to proteolysis in PhoA lipoproteins with differing +2 amino acids. This is the first study to examine the role of the +2 amino acid in mycoplasma lipoproteins and establish a difference between M. gallisepticum and Gram-positive and Gram-negative bacteria and will assist in optimization of the design of recombinant lipoprotein genes in mycoplasmas for maximal levels of expression and stability on the cell surface.
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Affiliation(s)
- Indu S Panicker
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Anna Kanci
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Philip F Markham
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Glenn F Browning
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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Khosa S, Lagedroste M, Smits SHJ. Protein Defense Systems against the Lantibiotic Nisin: Function of the Immunity Protein NisI and the Resistance Protein NSR. Front Microbiol 2016; 7:504. [PMID: 27148193 PMCID: PMC4828448 DOI: 10.3389/fmicb.2016.00504] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/29/2016] [Indexed: 12/01/2022] Open
Abstract
Lantibiotics are potential alternatives to antibiotics because of their broad-range killing spectrum. The producer strain is immune against its own synthesized lantibiotic via the expression of two proteins LanI and LanFEG. Recently, gene operons are found in mainly human pathogenic strains, which confer resistance against lantibiotics. Of all the lantibiotics discovered till date, nisin produced by some Lactococcus lactis strains is the most prominent member. Nisin has multiple mode of actions of which binding to the cell wall precursor lipid II and subsequent insertion into the bacterial membrane to form pores are the most effective. The nisin producing strains express the lipoprotein NisI to prevent a suicidal effect. NisI binds nisin, inducing a reversible cell clustering to prevent nisin from reaching the membrane. Importantly NisI does not modify nisin and releases it as soon as the concentration in the media drops below a certain level. The human pathogen Streptococcus agalactiae is naturally resistant against nisin by expressing a resistance protein called SaNSR, which is a nisin degrading enzyme. By cleaving off the last six amino acids of nisin, its effectiveness is 100-fold reduced. This cleavage reaction appears to be specific for nisin since SaNSR recognizes the C-terminal located lanthionine rings. Recently, the structures of both NisI and SaNSR were determined by NMR and X-ray crystallography, respectively. Furthermore, for both proteins the binding site for nisin was determined. Within this review, the structures of both proteins and their different defense mechanisms are described.
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Affiliation(s)
- Sakshi Khosa
- Lantibiotic Immunity and Resistance, Institute of Biochemistry, Heinrich-Heine-University Duesseldorf, Germany
| | - Marcel Lagedroste
- Lantibiotic Immunity and Resistance, Institute of Biochemistry, Heinrich-Heine-University Duesseldorf, Germany
| | - Sander H J Smits
- Lantibiotic Immunity and Resistance, Institute of Biochemistry, Heinrich-Heine-University Duesseldorf, Germany
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Abstract
While significant protection from pneumococcal disease has been achieved by the use of polysaccharide and polysaccharide-protein conjugate vaccines, capsule-independent protection has been limited by serotype replacement along with disease caused by nonencapsulated Streptococcus pneumoniae (NESp). NESp strains compose approximately 3% to 19% of asymptomatic carriage isolates and harbor multiple antibiotic resistance genes. Surface proteins unique to NESp enhance colonization and virulence despite the lack of a capsule even though the capsule has been thought to be required for pneumococcal pathogenesis. Genes for pneumococcal surface proteins replace the capsular polysaccharide (cps) locus in some NESp isolates, and these proteins aid in pneumococcal colonization and otitis media (OM). NESp strains have been isolated from patients with invasive and noninvasive pneumococcal disease, but noninvasive diseases, specifically, conjunctivitis (85%) and OM (8%), are of higher prevalence. Conjunctival strains are commonly of the so-called classical NESp lineages defined by multilocus sequence types (STs) ST344 and ST448, while sporadic NESp lineages such as ST1106 are more commonly isolated from patients with other diseases. Interestingly, sporadic lineages have significantly higher rates of recombination than classical lineages. Higher rates of recombination can lead to increased acquisition of antibiotic resistance and virulence factors, increasing the risk of disease and hindering treatment. NESp strains are a significant proportion of the pneumococcal population, can cause disease, and may be increasing in prevalence in the population due to effects on the pneumococcal niche caused by pneumococcal vaccines. Current vaccines are ineffective against NESp, and further research is necessary to develop vaccines effective against both encapsulated and nonencapsulated pneumococci.
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Couto N, Martins J, Lourenço AM, Pomba C, Varela Coelho A. Identification of vaccine candidate antigens of Staphylococcus pseudintermedius by whole proteome characterization and serological proteomic analyses. J Proteomics 2016; 133:113-124. [DOI: 10.1016/j.jprot.2015.12.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 12/02/2015] [Accepted: 12/09/2015] [Indexed: 01/12/2023]
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Luo Z, Morey JR, McDevitt CA, Kobe B. Heterogeneous nucleation is required for crystallization of the ZnuA domain of pneumococcal AdcA. Acta Crystallogr F Struct Biol Commun 2015; 71:1459-64. [PMID: 26625286 PMCID: PMC4666472 DOI: 10.1107/s2053230x15021330] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/10/2015] [Indexed: 01/17/2023] Open
Abstract
Zn(2+) is an essential nutrient for all known forms of life. In the major human pathogen Streptococcus pneumoniae, the acquisition of Zn(2+) is facilitated by two Zn(2+)-specific solute-binding proteins: AdcA and AdcAII. To date, there has been a paucity of structural information on AdcA, which has hindered a deeper understanding of the mechanism underlying pneumococcal Zn(2+) acquisition. Native AdcA consists of two domains: an N-terminal ZnuA domain and a C-terminal ZinT domain. In this study, the ZnuA domain of AdcA was crystallized. The initial crystals of the ZnuA-domain protein were obtained using dried seaweed as a heterogeneous nucleating agent. No crystals were obtained in the absence of the heterogeneous nucleating agent. These initial crystals were subsequently used as seeds to produce diffraction-quality crystals. The crystals diffracted to 2.03 Å resolution and had the symmetry of space group P1. This study demonstrates the utility of heterogeneous nucleation. The solution of the crystal structures will lead to further understanding of Zn(2+) acquisition by S. pneumoniae.
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Affiliation(s)
- Zhenyao Luo
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
| | - Jacqueline R. Morey
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Christopher A. McDevitt
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Boštjan Kobe
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia
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Goolab S, Roth RL, van Heerden H, Crampton MC. Analyzing the molecular mechanism of lipoprotein localization in Brucella. Front Microbiol 2015; 6:1189. [PMID: 26579096 PMCID: PMC4623201 DOI: 10.3389/fmicb.2015.01189] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 10/12/2015] [Indexed: 01/18/2023] Open
Abstract
Bacterial lipoproteins possess diverse structure and functionality, ranging from bacterial physiology to pathogenic processes. As such many lipoproteins, originating from Brucella are exploited as potential vaccines to countermeasure brucellosis infection in the host. These membrane proteins are translocated from the cytoplasm to the cell membrane where they are anchored peripherally by a multifaceted targeting mechanism. Although much research has focused on the identification and classification of Brucella lipoproteins and their potential use as vaccine candidates for the treatment of Brucellosis, the underlying route for the translocation of these lipoproteins to the outer surface of the Brucella (and other pathogens) outer membrane (OM) remains mostly unknown. This is partly due to the complexity of the organism and evasive tactics used to escape the host immune system, the variation in biological structure and activity of lipoproteins, combined with the complex nature of the translocation machinery. The biosynthetic pathway of Brucella lipoproteins involves a distinct secretion system aiding translocation from the cytoplasm, where they are modified by lipidation, sorted by the lipoprotein localization machinery pathway and thereafter equipped for export to the OM. Surface localized lipoproteins in Brucella may employ a lipoprotein flippase or the β-barrel assembly complex for translocation. This review provides an overview of the characterized Brucella OM proteins that form part of the OM, including a handful of other characterized bacterial lipoproteins and their mechanisms of translocation. Lipoprotein localization pathways in gram negative bacteria will be used as a model to identify gaps in Brucella lipoprotein localization and infer a potential pathway. Of particular interest are the dual topology lipoproteins identified in Escherichia coli and Haemophilus influenza. The localization and topology of these lipoproteins from other gram negative bacteria are well characterized and may be useful to infer a solution to better understand the translocation process in Brucella.
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Affiliation(s)
- Shivani Goolab
- Protein Technologies, Biosciences, Council for Scientific and Industrial ResearchPretoria, South Africa
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of PretoriaPretoria, South Africa
| | - Robyn L. Roth
- Protein Technologies, Biosciences, Council for Scientific and Industrial ResearchPretoria, South Africa
| | - Henriette van Heerden
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of PretoriaPretoria, South Africa
| | - Michael C. Crampton
- Protein Technologies, Biosciences, Council for Scientific and Industrial ResearchPretoria, South Africa
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Nathani NM, Duggirala SM, Bhatt VD, Patel AK, Kothari RK, Joshi CG. Correlation between genomic analyses with metatranscriptomic study reveals various functional pathways ofClostridium sartagoformeAAU1, a buffalo rumen isolate. JOURNAL OF APPLIED ANIMAL RESEARCH 2015. [DOI: 10.1080/09712119.2015.1091346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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40
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Wendler S, Otto A, Ortseifen V, Bonn F, Neshat A, Schneiker-Bekel S, Walter F, Wolf T, Zemke T, Wehmeier UF, Hecker M, Kalinowski J, Becher D, Pühler A. Comprehensive proteome analysis of Actinoplanes sp. SE50/110 highlighting the location of proteins encoded by the acarbose and the pyochelin biosynthesis gene cluster. J Proteomics 2015; 125:1-16. [DOI: 10.1016/j.jprot.2015.04.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 04/02/2015] [Accepted: 04/12/2015] [Indexed: 01/05/2023]
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Bannantine JP, Stabel JR, Laws E, D. Cardieri MC, Souza CD. Mycobacterium avium Subspecies paratuberculosis Recombinant Proteins Modulate Antimycobacterial Functions of Bovine Macrophages. PLoS One 2015; 10:e0128966. [PMID: 26076028 PMCID: PMC4468122 DOI: 10.1371/journal.pone.0128966] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/04/2015] [Indexed: 01/14/2023] Open
Abstract
It has been shown that Mycobacterium avium subspecies paratuberculosis (M. paratuberculosis) activates the Mitogen Activated Protein Kinase (MAPK) p38 pathway, yet it is unclear which components of M. paratuberculosis are involved in the process. Therefore, a set of 42 M. paratuberculosis recombinant proteins expressed from coding sequences annotated as lipoproteins were screened for their ability to induce IL-10 expression, an indicator of MAPKp38 activation, in bovine monocyte-derived macrophages. A recombinant lipoprotein, designated as MAP3837c, was among a group of 6 proteins that strongly induced IL-10 gene transcription in bovine macrophages, averaging a 3.1-fold increase compared to non-stimulated macrophages. However, a parallel increase in expression of IL-12 and TNF-α was only observed in macrophages exposed to a subset of these 6 proteins. Selected recombinant proteins were further analyzed for their ability to enhance survival of M. avium within bovine macrophages as measured by recovered viable bacteria and nitrite production. All 6 IL-10 inducing MAP recombinant proteins along with M. paratuberculosis cells significantly enhanced phosphorylation of MAPK-p38 in bovine macrophages. Although these proteins are likely not post translationally lipidated in E. coli and thus is a limitation in this study, these results form the foundation of how the protein component of the lipoprotein interacts with the immune system. Collectively, these data reveal M. paratuberculosis proteins that might play a role in MAPK-p38 pathway activation and hence in survival of this organism within bovine macrophages.
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Affiliation(s)
- John P. Bannantine
- National Animal Disease Center, USDA-Agricultural Research Service, Ames, Iowa, United States of America
| | - Judith R. Stabel
- National Animal Disease Center, USDA-Agricultural Research Service, Ames, Iowa, United States of America
| | - Elizabeth Laws
- Department of Veterinary Clinical Sciences, Washington State University, Pullman, Washington, United States of America
| | - Maria Clara D. Cardieri
- Department of Veterinary Clinical Sciences, Washington State University, Pullman, Washington, United States of America
| | - Cleverson D. Souza
- Department of Veterinary Clinical Sciences, Washington State University, Pullman, Washington, United States of America
- * E-mail:
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Morey JR, McDevitt CA, Kehl-Fie TE. Host-imposed manganese starvation of invading pathogens: two routes to the same destination. Biometals 2015; 28:509-19. [PMID: 25836716 PMCID: PMC4430393 DOI: 10.1007/s10534-015-9850-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/24/2015] [Indexed: 01/07/2023]
Abstract
During infection invading pathogens must acquire all essential nutrients, including first row transition metals, from the host. To combat invaders, the host exploits this fact and restricts the availability of these nutrients using a defense mechanism known as nutritional immunity. While iron sequestration is the most well-known aspect of this defense, recent work has revealed that the host restricts the availability of other essential elements, notably manganese (Mn), during infection. Furthermore, these studies have revealed that the host utilizes multiple strategies that extend beyond metal sequestration to prevent bacteria from obtaining these metals. This review will discuss the mechanisms by which bacteria attempt to obtain the essential first row transition metal ion Mn during infection, and the approaches utilized by the host to prevent this occurrence. In addition, this review will discuss the impact of host-imposed Mn starvation on invading bacteria.
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Affiliation(s)
- Jacqueline R. Morey
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Christopher A. McDevitt
- Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Thomas E. Kehl-Fie
- Department of Microbiology, University of Illinois Urbana-Champaign, Urbana IL, USA
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Arnaouteli S, Giastas P, Andreou A, Tzanodaskalaki M, Aldridge C, Tzartos SJ, Vollmer W, Eliopoulos E, Bouriotis V. Two Putative Polysaccharide Deacetylases Are Required for Osmotic Stability and Cell Shape Maintenance in Bacillus anthracis. J Biol Chem 2015; 290:13465-78. [PMID: 25825488 PMCID: PMC4505593 DOI: 10.1074/jbc.m115.640029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Indexed: 11/26/2022] Open
Abstract
Membrane-anchored lipoproteins have a broad range of functions and play key roles in several cellular processes in Gram-positive bacteria. BA0330 and BA0331 are the only lipoproteins among the 11 known or putative polysaccharide deacetylases of Bacillus anthracis. We found that both lipoproteins exhibit unique characteristics. BA0330 and BA0331 interact with peptidoglycan, and BA0330 is important for the adaptation of the bacterium to grow in the presence of a high concentration of salt, whereas BA0331 contributes to the maintenance of a uniform cell shape. They appear not to alter the peptidoglycan structure and do not contribute to lysozyme resistance. The high resolution x-ray structure of BA0330 revealed a C-terminal domain with the typical fold of a carbohydrate esterase 4 and an N-terminal domain unique for this family, composed of a two-layered (4 + 3) β-sandwich with structural similarity to fibronectin type 3 domains. Our data suggest that BA0330 and BA0331 have a structural role in stabilizing the cell wall of B. anthracis.
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Affiliation(s)
- Sofia Arnaouteli
- From the Department of Biology, Enzyme Biotechnology Group, University of Crete, Vasilika Vouton, 70013 Heraklion, Crete, Greece
| | - Petros Giastas
- the Department of Neurobiology, Hellenic Pasteur Institute, Vasilissis Sofias 127, 11521 Athens, Greece
| | - Athina Andreou
- the Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Mary Tzanodaskalaki
- the Institute of Molecular Biology and Biotechnology, 70013 Heraklion, Crete, Greece
| | - Christine Aldridge
- the Institute for Cell and Molecular Biosciences, Centre for Bacterial Cell Biology, Newcastle University, NE2 4AX Newcastle upon Tyne, United Kingdom, and
| | - Socrates J Tzartos
- the Department of Neurobiology, Hellenic Pasteur Institute, Vasilissis Sofias 127, 11521 Athens, Greece, the Department of Pharmacy, University of Patras, 26504, Patras, Greece
| | - Waldemar Vollmer
- the Institute for Cell and Molecular Biosciences, Centre for Bacterial Cell Biology, Newcastle University, NE2 4AX Newcastle upon Tyne, United Kingdom, and
| | - Elias Eliopoulos
- the Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Vassilis Bouriotis
- From the Department of Biology, Enzyme Biotechnology Group, University of Crete, Vasilika Vouton, 70013 Heraklion, Crete, Greece, the Institute of Molecular Biology and Biotechnology, 70013 Heraklion, Crete, Greece,
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Zou J, Wang X, Tian M, Cao S, Hou W, Wang S, Han X, Ding C, Yu S. The M949_1556 gene plays a role on the bacterial antigenicity and pathogenicity of Riemerella anatipestifer. Vet Microbiol 2015; 177:193-200. [PMID: 25804836 DOI: 10.1016/j.vetmic.2015.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 11/16/2022]
Abstract
Riemerella anatipestifer is one of the most economically important pathogens of farm ducks worldwide. However, the molecular mechanisms regarding its antigenicity and pathogenicity are poorly understood. We previously constructed a library of random Tn4351 transposon mutants using R. anatipestifer strain CH3. In this study, M949_1556 gene inactivated mutant strain CH3ΔM949_1556 was identified by screening of the library using monoclonal antibody against R. anatipestifer serotype 1 lipopolysaccharide (LPS) (anti-LPS MAb) followed by sequence analysis. The mutant strain presented no reactivity to the anti-LPS MAb in an indirect ELISA. Animal studies showed that the median lethal dose (LD50) of CH3ΔM949_1556 was >10(10) colony forming units (CFU), which was attenuated more than 50 times, compared with that of wild-type strain CH3 (LD50=2×10(8) CFU). The bacterial loads in the blood of CH3ΔM949_1556 infected ducks were significantly decreased, compared with those of CH3-infected ducks. In addition, CH3ΔM949_1556 presented significant, higher susceptibility to complement-dependent killing than CH3 did in vitro. Furthermore, CH3ΔM949_1556 showed increased bacterial adhesion and invasion capacities to Vero cells. Immunization with CH3ΔM949_1556-inactived vaccine was effective in protecting the ducks from challenge with R. anatipestifer serotype 1 strain WJ4, serotype 2 strain Yb2 and serotype 10 strain HXb2, suggesting that the mutant strain CH3ΔM949_1556 could provide a broad cross-protection among R. anatipestifer serotypes 1, 2 and 10 strains. Our results demonstrated that the M949_1556 gene plays a role on the bacterial antigenicity and pathogenicity of R. anatipestifer.
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Affiliation(s)
- Jiechi Zou
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Xiaolan Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Mingxing Tian
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Shoulin Cao
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Wanwan Hou
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Shaohui Wang
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Xiangan Han
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China
| | - Shengqing Yu
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, China.
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Gélis-Jeanvoine S, Lory S, Oberto J, Buddelmeijer N. Residues located on membrane-embedded flexible loops are essential for the second step of the apolipoprotein N-acyltransferase reaction. Mol Microbiol 2015; 95:692-705. [PMID: 25471278 DOI: 10.1111/mmi.12897] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2014] [Indexed: 11/30/2022]
Abstract
Apolipoprotein N-acyltransferase (Lnt) is an essential membrane-bound enzyme that catalyzes the third and last step in the post-translational modification of bacterial lipoproteins. In order to identify essential residues implicated in substrate recognition and/or binding we screened for non-functional variants of Lnt obtained by error-prone polymerase chain reaction in a complementation assay using a lnt depletion strain. Mutations included amino acid substitutions in the active site and of residues located on flexible loops in the catalytic periplasmic domain. All, but one mutation, led to the formation of the thioester acyl-enzyme intermediate and to the accumulation of apo-Lpp, suggesting that these residues are involved in the second step of the reaction. A large cytoplasmic loop contains a highly conserved region and two hydrophobic segments. Accessibility analysis to alkylating reagents of substituted cysteine residues introduced in this region demonstrated that the hydrophobic segments do not completely span the membrane. Two residues in the highly conserved cytoplasmic region were shown to be essential for Lnt function. Together, our data suggest that amino acids located on flexible cytoplasmic and periplasmic loops, predicted to be membrane embedded, are required for efficient N-acylation of lipoproteins.
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Affiliation(s)
- Sébastien Gélis-Jeanvoine
- Institut Pasteur, Biology and Genetics of the Bacterial Cell Wall Unit, Inserm Group Avenir, 28 rue du docteur Roux, Paris, F-75724 cedex 15, France
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Abstract
Gram-positive Streptococcus species are responsible for millions of cases of meningitis, bacterial pneumonia, endocarditis, erysipelas and necrotizing fasciitis. Iron is essential for the growth and survival of Streptococcus in the host environment. Streptococcus species have developed various mechanisms to uptake iron from an environment with limited available iron. Streptococcus can directly extract iron from host iron-containing proteins such as ferritin, transferrin, lactoferrin and hemoproteins, or indirectly by relying on the employment of specialized secreted hemophores (heme chelators) and small siderophore molecules (high affinity ferric chelators). This review presents the most recent discoveries in the iron acquisition system of Streptococcus species - the transporters as well as the regulators.
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Affiliation(s)
- Ruiguang Ge
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-Sen University, Guangzhou 510275, China.
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LprG-mediated surface expression of lipoarabinomannan is essential for virulence of Mycobacterium tuberculosis. PLoS Pathog 2014; 10:e1004376. [PMID: 25232742 PMCID: PMC4169494 DOI: 10.1371/journal.ppat.1004376] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 07/28/2014] [Indexed: 11/19/2022] Open
Abstract
Mycobacterium tuberculosis employs various virulence strategies to subvert host immune responses in order to persist and cause disease. Interaction of M. tuberculosis with mannose receptor on macrophages via surface-exposed lipoarabinomannan (LAM) is believed to be critical for cell entry, inhibition of phagosome-lysosome fusion, and intracellular survival, but in vivo evidence is lacking. LprG, a cell envelope lipoprotein that is essential for virulence of M. tuberculosis, has been shown to bind to the acyl groups of lipoglycans but the role of LprG in LAM biosynthesis and localization remains unknown. Using an M. tuberculosis lprG mutant, we show that LprG is essential for normal surface expression of LAM and virulence of M. tuberculosis attributed to LAM. The lprG mutant had a normal quantity of LAM in the cell envelope, but its surface was altered and showed reduced expression of surface-exposed LAM. Functionally, the lprG mutant was defective for macrophage entry and inhibition of phagosome-lysosome fusion, was attenuated in macrophages, and was killed in the mouse lung with the onset of adaptive immunity. This study identifies the role of LprG in surface-exposed LAM expression and provides in vivo evidence for the essential role surface LAM plays in M. tuberculosis virulence. Findings have translational implications for therapy and vaccine development. Mycobacterium tuberculosis is among the leading infectious causes of human death. A better understanding of its virulence mechanisms is needed to facilitate development of novel therapeutics and a preventative vaccine. Lipoarabinomannan (LAM), an abundant surface-exposed lipoglycan, is believed to be a critical virulence determinant for intracellular survival and latency of M. tuberculosis. In vitro experiments with purified LAM have led to a model in which surface-exposed LAM binds to macrophage mannose receptor and facilitates bacterium entry, inhibition of phagosome-lysosome fusion, and modulation of innate immune responses. However, confirmation of these findings in vivo has not been possible due to the essentiality of genes involved in the LAM biosynthetic pathway. It was recently shown that LprG, a cell envelope lipoprotein, binds to the acyl groups of lipoglycan, but the role of LprG in LAM biosynthesis and localization remains unknown. Here, using an M. tuberculosis lprG mutant and a novel cell-imprinting assay, we show that LprG is essential for normal surface expression of LAM and virulence of M. tuberculosis attributed to LAM. Our study provides new insights into the mechanism of surface expression of LAM and confirms the essential role surface LAM serves in pathogenesis of M. tuberculosis.
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Kunii M, Arimoto T, Hasegawa T, Kuwata H, Igarashi T. Role of protease maturation lipoprotein in osmoadaptation of Streptococcus mutans. FEMS Microbiol Lett 2014; 356:45-52. [PMID: 24863612 DOI: 10.1111/1574-6968.12477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 05/16/2014] [Accepted: 05/22/2014] [Indexed: 12/18/2022] Open
Abstract
Osmoadaptation may be an important trait for the pathogenicity of Streptococcus mutans. However, how this organism adapts to changes in osmolality in the oral cavity remains unclear. In this study, we showed that S. mutans utilizes K(+) for osmoadaptation, in which protease maturation lipoprotein (PrtM) plays an important role. Although growth of the wild-type strain was impaired in a hyperosmotic medium [brain heart infusion (BHI) containing 0.3 M NaCl] compared with that in an unmodified BHI, the prtM mutant grew much more poorly in 0.3 M NaCl BHI. Comparison of growth behavior in the hyperosmotic medium supplemented with different osmoprotectants revealed that only the addition of K(+) allowed the bacteria to overcome the impairment of growth caused by the high osmolality. These results suggest that K(+) is an important compatible solute for S. mutans. Moreover, K(+) -associated recovery of growth was not observed for the prtM mutant, indicating that PrtM plays a critical role in the utilization of K(+) . Quantitative reverse-transcriptase polymerase chain reaction analysis showed that prtM was induced by osmotic stress, implying that prtM is an osmoresponsive gene. These findings suggest that K(+) is an important compatible solute for S. mutans, and that the osmoresponsive lipoprotein PrtM is involved in K(+) utilization, contributing to osmoadaptation of S. mutans.
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Affiliation(s)
- Maiko Kunii
- Department of Oral Microbiology and Immunology, Showa University School of Dentistry, Tokyo, Japan; Division of Comprehensive Dentistry, Department of Conservative Dentistry, Showa University School of Dentistry, Tokyo, Japan
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Siljamäki P, Varmanen P, Kankainen M, Sukura A, Savijoki K, Nyman TA. Comparative exoprotein profiling of different Staphylococcus epidermidis strains reveals potential link between nonclassical protein export and virulence. J Proteome Res 2014; 13:3249-61. [PMID: 24840314 DOI: 10.1021/pr500075j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Staphylococcus epidermidis (SE) includes commensal and pathogenic strains capable of infecting humans and animals. This study reports global exoproteome profiling of bovine mastitis strain PM221 and two human strains, commensal-type ATCC12228 and sepsis-associated RP62A. We identified 451, 395, and 518 proteins from culture supernatants of PM221, ATCC12228, and RP62A, respectively. Comparison of the identified exoproteomes revealed several strain-specific differences related to secreted antigens and adhesins, higher virulence capability for RP62A, and similarities between the PM221 and RP62A exoproteomes. The majority of the identified proteins (∼80%) were predicted to be cytoplasmic, including proteins known to be associated in membrane vesicles (MVs) in Staphylococcus aureus and immunogenic/adhesive moonlighting proteins. Enrichment of MV fractions from culture supernatants and analysis of their protein composition indicated that this nonclassical protein secretion pathway was being exploited under the conditions used and that there are strain-specific differences in nonclassical protein export. In addition, several predicted cell-surface proteins were identified in the culture media. In summary, the present study is the first in-depth exoproteome analysis of SE highlighting strain-specific factors able to contribute to virulence and adaptation.
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Affiliation(s)
- Pia Siljamäki
- Department of Food and Environmental Sciences, ‡Institute of Biotechnology, and §Department of Veterinary Biosciences, University of Helsinki , FI-00014 Helsinki, Finland
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Carvalho F, Sousa S, Cabanes D. How Listeria monocytogenes organizes its surface for virulence. Front Cell Infect Microbiol 2014; 4:48. [PMID: 24809022 PMCID: PMC4010754 DOI: 10.3389/fcimb.2014.00048] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 04/02/2014] [Indexed: 02/04/2023] Open
Abstract
Listeria monocytogenes is a Gram-positive pathogen responsible for the manifestation of human listeriosis, an opportunistic foodborne disease with an associated high mortality rate. The key to the pathogenesis of listeriosis is the capacity of this bacterium to trigger its internalization by non-phagocytic cells and to survive and even replicate within phagocytes. The arsenal of virulence proteins deployed by L. monocytogenes to successfully promote the invasion and infection of host cells has been progressively unveiled over the past decades. A large majority of them is located at the cell envelope, which provides an interface for the establishment of close interactions between these bacterial factors and their host targets. Along the multistep pathways carrying these virulence proteins from the inner side of the cytoplasmic membrane to their cell envelope destination, a multiplicity of auxiliary proteins must act on the immature polypeptides to ensure that they not only maturate into fully functional effectors but also are placed or guided to their correct position in the bacterial surface. As the major scaffold for surface proteins, the cell wall and its metabolism are critical elements in listerial virulence. Conversely, the crucial physical support and protection provided by this structure make it an ideal target for the host immune system. Therefore, mechanisms involving fine modifications of cell envelope components are activated by L. monocytogenes to render it less recognizable by the innate immunity sensors or more resistant to the activity of antimicrobial effectors. This review provides a state-of-the-art compilation of the mechanisms used by L. monocytogenes to organize its surface for virulence, with special focus on those proteins that work “behind the frontline”, either supporting virulence effectors or ensuring the survival of the bacterium within its host.
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Affiliation(s)
- Filipe Carvalho
- Group of Molecular Microbiology, Unit of Infection and Immunity, Instituto de Biologia Molecular e Celular, University of Porto Porto, Portugal
| | - Sandra Sousa
- Group of Molecular Microbiology, Unit of Infection and Immunity, Instituto de Biologia Molecular e Celular, University of Porto Porto, Portugal
| | - Didier Cabanes
- Group of Molecular Microbiology, Unit of Infection and Immunity, Instituto de Biologia Molecular e Celular, University of Porto Porto, Portugal
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