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Wan Q, Zhai S, Chen M, Xu M, Guo S. Comparative phenotype and transcriptome analysis revealed the role of ferric uptake regulator (Fur) in the virulence of Vibrio harveyi isolated from diseased American eel (Anguilla rostrata). JOURNAL OF FISH DISEASES 2024; 47:e13931. [PMID: 38373044 DOI: 10.1111/jfd.13931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 02/20/2024]
Abstract
Vibrio harveyi is commonly found in salt and brackish water and is recognized as a serious bacterial pathogen in aquaculture worldwide. In this study, we cloned the ferric uptake regulator (fur) gene from V. harveyi wild-type strain HA_1, which was isolated from diseased American eels (Anguilla rostrata) and has a length of 450 bp, encoding 149 amino acids. Then, a mutant strain, HA_1-Δfur, was constructed through homologous recombination of a suicide plasmid (pCVD442). The HA_1-Δfur mutant exhibited weaker biofilm formation and swarming motility, and 18-fold decrease (5.5%) in virulence to the American eels; compared to the wild-type strain, the mutant strain showed time and diameter differences in growth and haemolysis, respectively. Additionally, the adhesion ability of the mutant strain was significantly decreased. Moreover, there were 15 different biochemical indicators observed between the two strains. Transcriptome analysis revealed that 875 genes were differentially expressed in the Δfur mutant, with 385 up-regulated and 490 down-regulated DEGs. GO and KEGG enrichment analysis revealed that, compared to the wild-type strain, the type II and type VI secretion systems (T2SS and T6SS), amino acid synthesis and transport and energy metabolism pathways were significantly down-regulated, but the ABC transporters and biosynthesis of siderophore group non-ribosomal peptides pathways were up-regulated in the Δfur strain. The qRT-PCR results further confirmed that DEGs responsible for amino acid transport and energy metabolism were positively regulated, but DEGs involved in iron acquisition were negatively regulated in the Δfur strain. These findings suggest that the virulence of the Δfur strain was significantly decreased, which is closely related to phenotype changing and gene transcript regulation.
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Affiliation(s)
- Qijuan Wan
- Fisheries College of Jimei University/Engineering Research Center of the Modern Industry Technology for Eel, Ministry of Education of PRC, Xiamen, China
- State Key Laboratory of Mariculture Breeding, Fisheries College of Jimei University, Xiamen, China
| | - Shaowei Zhai
- Fisheries College of Jimei University/Engineering Research Center of the Modern Industry Technology for Eel, Ministry of Education of PRC, Xiamen, China
- State Key Laboratory of Mariculture Breeding, Fisheries College of Jimei University, Xiamen, China
| | - Minxia Chen
- Fisheries College of Jimei University/Engineering Research Center of the Modern Industry Technology for Eel, Ministry of Education of PRC, Xiamen, China
- State Key Laboratory of Mariculture Breeding, Fisheries College of Jimei University, Xiamen, China
| | - Ming Xu
- Fisheries College of Jimei University/Engineering Research Center of the Modern Industry Technology for Eel, Ministry of Education of PRC, Xiamen, China
- State Key Laboratory of Mariculture Breeding, Fisheries College of Jimei University, Xiamen, China
| | - Songlin Guo
- Fisheries College of Jimei University/Engineering Research Center of the Modern Industry Technology for Eel, Ministry of Education of PRC, Xiamen, China
- State Key Laboratory of Mariculture Breeding, Fisheries College of Jimei University, Xiamen, China
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2
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Cheng Y, Zhu W, Han S, Yang J, Wu G, Zhao G, He X. Roseomonas populi sp. nov., an acetate-degrading bacteria isolated from the stem of Populus tomentosa. Antonie Van Leeuwenhoek 2023; 117:2. [PMID: 38147266 DOI: 10.1007/s10482-023-01911-3] [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: 07/11/2023] [Accepted: 10/24/2023] [Indexed: 12/27/2023]
Abstract
Strain CN29T, isolated from the stem of 5- to 6-year-old Populus tomentosa in Shandong, China, was characterized using a polyphasic taxonomic approach. Cells of CN29T were Gram-stain negative, aerobic, nonspore-forming, and nonmotile coccoid. Growth occurred at 20-37 °C, pH 4.0-9.0 (optimum, pH 6.0), and with 0-1% NaCl (optimum, 1%). Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain CN29T was closely related to members of the genus Roseomonas and closest to Roseomonas pecuniae N75T (96.6%). This classification was further supported by phylogenetic analysis using additional core genes. The average nucleotide identity and digital DNA‒DNA hybridization values between strain CN29T and Roseomonas populi CN29T were 82.7% and 27.8%, respectively. The genome size of strain CN29T was 5.87 Mb, with a G + C content of 70.9%. The major cellular fatty acids included summed feature 8 (C18:1 ω7c/C18:1 ω6c), C19:0 cyclo ω8c and C16:0. The major respiratory quinone was Q-10. The polar lipids were phosphatidylcholine, aminolipid, phosphatidylglycerol, and diphosphatidylglycerol. Strain CN29T can utilize acetate as a carbon source for growth and metabolism. Additionally, it contains acid phosphatase (2-naphthyl phosphate), which catalyzes the hydrolysis of phosphoric monoesters. The CN29T strain contains several genes, including maeB, gdhB, and cysJ, involved in carbon, nitrogen, and sulfur cycling. These findings suggest that the strain may actively participate in ecosystem cycling, leading to soil improvement and promoting the growth of poplar trees. Based on the phylogenetic, phenotypic, and genotypic characteristics, strain CN29T is concluded to represent a novel species of the genus Roseomonas, for which the name Roseomonas populi sp. nov. is proposed. The type strain is CN29T (= JCM 35579T = GDMCC 1.3267T).
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Affiliation(s)
- Yao Cheng
- Beijing Key Laboratory of Food Processing and Safety, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Wen Zhu
- Beijing Key Laboratory of Food Processing and Safety, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Shuo Han
- Beijing Key Laboratory of Food Processing and Safety, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Jingjing Yang
- Beijing Key Laboratory of Food Processing and Safety, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Guanqi Wu
- Beijing Key Laboratory of Food Processing and Safety, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Guozhu Zhao
- Beijing Key Laboratory of Food Processing and Safety, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China
| | - Xiangwei He
- Beijing Key Laboratory of Food Processing and Safety, College of Biological Sciences and Technology, Beijing Forestry University, Beijing, 100083, China.
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3
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Barbat B, Douzi B, Ball G, Tribout M, El Karkouri K, Kellenberger C, Voulhoux R. Insights into dynamics and gating properties of T2SS secretins. SCIENCE ADVANCES 2023; 9:eadg6996. [PMID: 37792935 PMCID: PMC10550240 DOI: 10.1126/sciadv.adg6996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 09/05/2023] [Indexed: 10/06/2023]
Abstract
Secretins are outer membrane (OM) channels found in various bacterial nanomachines that secrete or assemble large extracellular structures. High-resolution 3D structures of type 2 secretion system (T2SS) secretins revealed bimodular channels with a C-module, holding a conserved central gate and an optional top gate, followed by an N-module for which multiple structural organizations have been proposed. Here, we perform a structure-driven in vivo study of the XcpD secretin, which validates one of the organizations of the N-module whose flexibility enables alternative conformations. We also show the existence of the central gate in vivo and its required flexibility, which is key for substrate passage and watertightness control. Last, functional, genomic, and phylogenetic analyses indicate that the optional top gate provides a gain of watertightness. Our data illustrate how the gating properties of T2SS secretins allow these large channels to overcome the duality between the necessity of preserving the OM impermeability while simultaneously promoting the secretion of large, folded effectors.
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Affiliation(s)
- Brice Barbat
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
| | - Badreddine Douzi
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
- Université de Lorraine, INRAE, DynAMic, Nancy, F-54000 France
| | - Geneviève Ball
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
| | - Mathilde Tribout
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
| | | | | | - Romé Voulhoux
- LCB-UMR7283, CNRS, Aix Marseille Université, IMM, Marseille, France
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4
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Fan Z, Fu T, Li Z, Du B, Cui X, Zhang R, Feng Y, Zhao H, Xue G, Cui J, Yan C, Gan L, Feng J, Xu Z, Yu Z, Tian Z, Ding Z, Chen J, Chen Y, Yuan J. The role of integration host factor in biofilm and virulence of high-alcohol-producing Klebsiella pneumoniae. Microbiol Spectr 2023; 11:e0117023. [PMID: 37732783 PMCID: PMC10581059 DOI: 10.1128/spectrum.01170-23] [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: 03/20/2023] [Accepted: 07/28/2023] [Indexed: 09/22/2023] Open
Abstract
Klebsiella pneumoniae is a well-known human nosocomial pathogen with an arsenal of virulence factors, including capsular polysaccharides (CPS), fimbriae, flagella, and lipopolysaccharides (LPS). Our previous study found that alcohol acted as an essential virulence factor for high-alcohol-producing K. pneumoniae (HiAlc Kpn). Integration host factor (IHF) is a nucleoid-associated protein that functions as a global virulence regulator in Escherichia coli. However, the regulatory role of IHF in K. pneumoniae remains unknown. In the present study, we found that deletion of ihfA or ihfB resulted in a slight defect in bacterial growth, a severe absence of biofilm formation and cytotoxicity, and a significant reduction in alcohol production. RNA sequencing differential gene expression analysis showed that compared with the wild-type control, the expression of many virulence factor genes was downregulated in ΔihfA and ΔihfB strains, such as those related to CPS (rcsA, galF, wzi, and iscR), LPS (rfbABCD), type I and type III fimbriae (fim and mrk operon), cellulose (bcs operon), iron transporter (feoABC, fhuA, fhuF, tonB, exbB, and exbD), quorum sensing (lsr operon and sdiA), type II secretion system (T2SS) and type VI secretion system (T6SS) (tssG, hcp, and gspE). Of these virulence factors, CPS, LPS, fimbriae, and cellulose are involved in biofilm formation. In addition, IHF could affect the alcohol production by regulating genes related to glucose intake (ptsG), pyruvate formate-lyase, alcohol dehydrogenase, and the tricarboxylic acid (TCA) cycle. Our data provided new insights into the importance of IHF in regulating the virulence of HiAlc Kpn. IMPORTANCE Klebsiella pneumoniae is a well-known human nosocomial pathogen that causes various infectious diseases, including urinary tract infections, hospital-acquired pneumonia, bacteremia, and liver abscesses. Our previous studies demonstrated that HiAlc Kpn mediated the development of nonalcoholic fatty liver disease by producing excess endogenous alcohol in vivo. However, the regulators regulating the expression of genes related to metabolism, biofilm formation, and virulence of HiAlc Kpn remain unclear. In this study, the regulator IHF was found to positively regulate biofilm formation and many virulence factors including CPS, LPS, type I and type III fimbriae, cellulose, iron transporter, AI-2 quorum sensing, T2SS, and T6SS in HiAlc Kpn. Furthermore, IHF positively regulated alcohol production in HiAlc Kpn. Our results suggested that IHF could be a potential drug target for treating various infectious diseases caused by K. pneumoniae. Hence, the regulation of different virulence factors by IHF in K. pneumoniae requires further investigation.
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Affiliation(s)
- Zheng Fan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Tongtong Fu
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Zhoufei Li
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
| | - Bing Du
- University of Edinburgh, Edinburgh, United Kingdom
| | - Xiaohu Cui
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Rui Zhang
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
| | - Yanling Feng
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Hanqing Zhao
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Guanhua Xue
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Jinghua Cui
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Chao Yan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Lin Gan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Junxia Feng
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Ziying Xu
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Zihui Yu
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Ziyan Tian
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Zanbo Ding
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Jinfeng Chen
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Yujie Chen
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Jing Yuan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
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5
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Askarian F, Tsai CM, Cordara G, Zurich RH, Bjånes E, Golten O, Vinther Sørensen H, Kousha A, Meier A, Chikwati E, Bruun JA, Ludviksen JA, Choudhury B, Trieu D, Davis S, Edvardsen PKT, Mollnes TE, Liu GY, Krengel U, Conrad DJ, Vaaje-Kolstad G, Nizet V. Immunization with lytic polysaccharide monooxygenase CbpD induces protective immunity against Pseudomonas aeruginosa pneumonia. Proc Natl Acad Sci U S A 2023; 120:e2301538120. [PMID: 37459522 PMCID: PMC10372616 DOI: 10.1073/pnas.2301538120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 05/30/2023] [Indexed: 07/20/2023] Open
Abstract
Pseudomonas aeruginosa (PA) CbpD belongs to the lytic polysaccharide monooxygenases (LPMOs), a family of enzymes that cleave chitin or related polysaccharides. Here, we demonstrate a virulence role of CbpD in PA pneumonia linked to impairment of host complement function and opsonophagocytic clearance. Following intratracheal challenge, a PA ΔCbpD mutant was more easily cleared and produced less mortality than the wild-type parent strain. The x-ray crystal structure of the CbpD LPMO domain was solved to subatomic resolution (0.75Å) and its two additional domains modeled by small-angle X-ray scattering and Alphafold2 machine-learning algorithms, allowing structure-based immune epitope mapping. Immunization of naive mice with recombinant CbpD generated high IgG antibody titers that promoted human neutrophil opsonophagocytic killing, neutralized enzymatic activity, and protected against lethal PA pneumonia and sepsis. IgG antibodies generated against full-length CbpD or its noncatalytic M2+CBM73 domains were opsonic and protective, even in previously PA-exposed mice, while antibodies targeting the AA10 domain were not. Preexisting antibodies in PA-colonized cystic fibrosis patients primarily target the CbpD AA10 catalytic domain. Further exploration of LPMO family proteins, present across many clinically important and antibiotic-resistant human pathogens, may yield novel and effective vaccine antigens.
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Affiliation(s)
- Fatemeh Askarian
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
| | - Chih-Ming Tsai
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
| | | | - Raymond H. Zurich
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
| | - Elisabet Bjånes
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
| | - Ole Golten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432Ås, Norway
| | | | - Armin Kousha
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
| | - Angela Meier
- Division of Critical Care, Department of Anesthesiology, University of California San Diego, La Jolla, CA92037
| | - Elvis Chikwati
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, N-1432Ås, Norway
| | - Jack-Ansgar Bruun
- Proteomics and Metabolomics Core Facility, Department of Medical Biology, The Arctic University of Norway, N-9037Tromsø, Norway
| | | | - Biswa Choudhury
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA92093
| | - Desmond Trieu
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
- School of Pharmacy, University of California San Francisco, San Francisco, CA94143
| | - Stanley Davis
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
| | | | - Tom Eirik Mollnes
- Research Laboratory, Nordland Hospital, N-8005Bodø, Norway
- Department of Immunology, University of Oslo Hospital, N-0424Oslo, Norway
- Center of Molecular Inflammation Research, Norwegian University of Science and Technology, N-7491Trondheim, Norway
| | - George Y. Liu
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
| | - Ute Krengel
- Department of Chemistry, University of Oslo, N-0315Oslo, Norway
| | - Douglas J. Conrad
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California San Diego, La Jolla, CA92037
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, N-1432Ås, Norway
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, University of California San Diego, La Jolla, CA92093
- Glycobiology Research and Training Center, University of California San Diego, La Jolla, CA92093
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA92093
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6
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Yang M, Zhou X, Bao Y, Zhang Y, Liu B, Gan L, Tao W, Tuo J, Gong H. Comprehensive Genomic Analysis Reveals Extensive Diversity of Type I and Type IV Secretion Systems in Klebsiella pneumoniae. Curr Microbiol 2023; 80:270. [PMID: 37402963 DOI: 10.1007/s00284-023-03362-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Accepted: 06/02/2023] [Indexed: 07/06/2023]
Abstract
The diversity and distribution of secretion systems in Klebsiella pneumoniae are unclear. In this study, the six common secretion systems (T1SS-T6SS) were comprehensively investigated in the genomes of 952 K. pneumoniae strains. T1SS, T2SS, type T subtype of T4SS, T5SS, and subtype T6SSi of T6SS were found. The findings indicated fewer types of secretion systems in K. pneumoniae than reported in Enterobacteriaceae, such as Escherichia coli. One conserved T2SS, one conserved T5SS, and two conserved T6SS were detected in more than 90% of the strains. In contrast, the strains displayed extensive diversity of T1SS and T4SS. Notably, T1SS and T4SS were enriched in the hypervirulent and classical multidrug resistance pathotypes of K. pneumoniae, respectively. The results expand the epidemiological knowledge of the virulence and transmissibility of pathogenic K. pneumoniae and contribute to identify the potential strains for safe applications.
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Affiliation(s)
- Menglei Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Xiaoqin Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Yangyang Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Yang Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Boya Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Luxi Gan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Weihua Tao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Jinyou Tuo
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China
| | - Heng Gong
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
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7
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Sagoo J, Abedrabbo S, Liu X, Ottemann KM. Discovery of Type IV filament membrane alignment complex homologs in H. pylori that promote soft-agar migration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.27.537399. [PMID: 37163056 PMCID: PMC10168365 DOI: 10.1101/2023.04.27.537399] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The stomach pathogen Helicobacter pylori utilizes two scaffold proteins, CheW and CheV1, to build critical chemotaxis arrays. Chemotaxis helps bacteria establish and maintain infection. Mutants lacking either of these chemotaxis proteins have different soft agar phenotypes: deletion of cheW creates non-chemotactic strains, while deletion of cheV1 results in 50% loss of chemotaxis. In this work, we characterized the cheV1 deletion mutant phenotype in detail. cheV1 deletion mutants had poor soft-agar migration initially, but regained migration ability over time. This improved bacterial migration was stable, suggesting a genetic suppressor phenotype, termed Che+. Whole-genome sequencing analysis of four distinct cheV1 Che+ strains revealed single nucleotide polymorphisms (SNPs) in a common gene, HPG27_252 (HP0273). These SNPs were predicted to truncate the encoded protein. To confirm the role of HPG27_252 in the cheV1 phenotype, we created a targeted deletion of HPG27_252 and found that loss of HPG27_252 enhanced soft-agar migration. HPG27_252 and CheV1 appear to interact directly, based on bacterial two-hybrid analysis. HPG27_252 is predicted to encode a 179 amino acid, 21 kDa protein annotated as a hypothetical protein. Computational analysis revealed this protein to be a remote homolog of the PilO Type IV filament membrane alignment complex protein. Although H. pylori is not known to possess Type IV filaments, our analysis showed it retains an operon of genes for homologs of PilO, PilN, and PilM, but does not possess other Type IV pili genes. Our data suggest the PilO homolog plays a role in regulating H. pylori chemotaxis and motility, suggesting new ideas about evolutionary steps for controlling migration through semi-solid media.
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8
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Shaliutina-Loginova A, Francetic O, Doležal P. Bacterial Type II Secretion System and Its Mitochondrial Counterpart. mBio 2023; 14:e0314522. [PMID: 36971557 PMCID: PMC10128026 DOI: 10.1128/mbio.03145-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Over the billions of years that bacteria have been around, they have evolved several sophisticated protein secretion nanomachines to deliver toxins, hydrolytic enzymes, and effector proteins into their environments. Of these, the type II secretion system (T2SS) is used by Gram-negative bacteria to export a wide range of folded proteins from the periplasm across the outer membrane.
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9
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Dazzoni R, Li Y, López-Castilla A, Brier S, Mechaly A, Cordier F, Haouz A, Nilges M, Francetic O, Bardiaux B, Izadi-Pruneyre N. Structure and dynamic association of an assembly platform subcomplex of the bacterial type II secretion system. Structure 2023; 31:152-165.e7. [PMID: 36586404 DOI: 10.1016/j.str.2022.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 10/20/2022] [Accepted: 11/29/2022] [Indexed: 12/31/2022]
Abstract
Type II secretion systems (T2SSs) allow diderm bacteria to secrete hydrolytic enzymes, adhesins, or toxins important for growth and virulence. To promote secretion of folded proteins, T2SSs assemble periplasmic filaments called pseudopili or endopili at an inner membrane subcomplex, the assembly platform (AP). Here, we combined biophysical approaches, nuclear magnetic resonance (NMR) and X-ray crystallography, to study the Klebsiella AP components PulL and PulM. We determined the structure and associations of their periplasmic domains and describe the structure of the heterodimer formed by their ferredoxin-like domains. We show how structural complementarity and plasticity favor their association during the secretion process. Cysteine scanning and crosslinking data provided additional constraints to build a structural model of the PulL-PulM assembly in the cellular context. Our structural and functional insights, together with the relative cellular abundance of its components, support the role of AP as a dynamic hub that orchestrates pilus polymerization.
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Affiliation(s)
- Régine Dazzoni
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 75015 Paris, France
| | - Yuanyuan Li
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, 75015 Paris, France
| | - Aracelys López-Castilla
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 75015 Paris, France
| | - Sébastien Brier
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Biological NMR and HDX-MS Technological Platform, 75015 Paris, France
| | - Ariel Mechaly
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Crystallography Platform, 75015 Paris, France
| | - Florence Cordier
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 75015 Paris, France; Institut Pasteur, Université Paris Cité, CNRS UMR3528, Biological NMR and HDX-MS Technological Platform, 75015 Paris, France
| | - Ahmed Haouz
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Crystallography Platform, 75015 Paris, France
| | - Michael Nilges
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 75015 Paris, France
| | - Olivera Francetic
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, 75015 Paris, France
| | - Benjamin Bardiaux
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 75015 Paris, France; Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, 75015 Paris.
| | - Nadia Izadi-Pruneyre
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Structural Bioinformatics Unit, 75015 Paris, France; Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, 75015 Paris.
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10
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Xie J, Zhang H, Li Y, Li H, Pan Y, Zhao Y, Xie Q. Transcriptome analysis of the biofilm formation mechanism of Vibrio parahaemolyticus under the sub-inhibitory concentrations of copper and carbenicillin. Front Microbiol 2023; 14:1128166. [PMID: 36937277 PMCID: PMC10018186 DOI: 10.3389/fmicb.2023.1128166] [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: 12/20/2022] [Accepted: 02/13/2023] [Indexed: 03/06/2023] Open
Abstract
Biofilm formation of Vibrio parahaemolyticus enhanced its tolerance to the environment, but caused many serious problems to food safety and human health. In this paper, the effects of copper and carbenicillin (CARB) stress on the formation of the biofilms of V. parahaemolyticus organisms were studied, and RNA sequencing technology was used to compare the differences in transcriptome profiles of the biofilm-related genes of V. parahaemolyticus organisms under different sub-inhibitory stresses. The results proved that V. parahaemolyticus had a large growth difference under the two stresses, copper and CARB at 1/2 minimal inhibitory concentration (MIC), and it could form a stable biofilm under both stress conditions. The amount of biofilm formed under CARB stress was significantly higher than that of copper stress (p < 0.05). Based on the analysis of transcriptome sequencing results 323, 1,550, and 1,296 significantly differential expressed genes were identified in the three treatment groups namely 1/2 MIC CARB, Cu2+, and Cu2++CARB. Through COG annotation, KEGG metabolic pathway analysis and gene expression analysis related to biofilm formation, the functional pathways of transcriptome changes affecting V. parahaemolyticus were different in the three treatment groups, and the CARB treatment group was significantly different from the other two groups. These differences indicated that the ABC transport system, two-component system and quorum sensing were all involved in the biofilm formation of the V. parahaemolytic by regulating flagellar motility, extracellular polysaccharides and extracellular polymer synthesis. Exploring the effects of different stress conditions on the transcriptome of V. parahaemolyticus could provide a basis for future research on the complex network system that regulates the formation of bacterial biofilms.
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Affiliation(s)
- Jiaying Xie
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Hongmin Zhang
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Yinhui Li
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Hao Li
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Yingjie Pan
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Product on Storage and Preservation, Ministry of Agriculture and Rural Affairs, Shanghai, China
- Shanghai Engineering Research Center of Aquatic Product Processing and Preservation, Shanghai, China
| | - Yong Zhao
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Product on Storage and Preservation, Ministry of Agriculture and Rural Affairs, Shanghai, China
- Shanghai Engineering Research Center of Aquatic Product Processing and Preservation, Shanghai, China
- *Correspondence: Yong Zhao,
| | - Qingchao Xie
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality and Safety Risk Assessment for Aquatic Product on Storage and Preservation, Ministry of Agriculture and Rural Affairs, Shanghai, China
- Qingchao Xie,
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11
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cGenomic characteristics of a notable emerging serotype O10:K4 of Vibrio parahaemolyticus from food-borne cluster events in Guangzhou, China. J Infect 2022; 85:702-769. [PMID: 36152735 DOI: 10.1016/j.jinf.2022.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 09/12/2022] [Indexed: 10/14/2022]
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12
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Dade CM, Douzi B, Cambillau C, Ball G, Voulhoux R, Forest KT. The crystal structure of CbpD clarifies substrate-specificity motifs in chitin-active lytic polysaccharide monooxygenases. Acta Crystallogr D Struct Biol 2022; 78:1064-1078. [PMID: 35916229 PMCID: PMC9344471 DOI: 10.1107/s2059798322007033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 07/08/2022] [Indexed: 11/23/2022] Open
Abstract
Pseudomonas aeruginosa secretes diverse proteins via its type 2 secretion system, including a 39 kDa chitin-binding protein, CbpD. CbpD has recently been shown to be a lytic polysaccharide monooxygenase active on chitin and to contribute substantially to virulence. To date, no structure of this virulence factor has been reported. Its first two domains are homologous to those found in the crystal structure of Vibrio cholerae GbpA, while the third domain is homologous to the NMR structure of the CBM73 domain of Cellvibrio japonicus CjLPMO10A. Here, the 3.0 Å resolution crystal structure of CbpD solved by molecular replacement is reported, which required ab initio models of each CbpD domain generated by the artificial intelligence deep-learning structure-prediction algorithm RoseTTAFold. The structure of CbpD confirms some previously reported substrate-specificity motifs among LPMOAA10s, while challenging the predictive power of others. Additionally, the structure of CbpD shows that post-translational modifications occur on the chitin-binding surface. Moreover, the structure raises interesting possibilities about how type 2 secretion-system substrates may interact with the secretion machinery and demonstrates the utility of new artificial intelligence protein structure-prediction algorithms in making challenging structural targets tractable.
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Affiliation(s)
- Christopher M. Dade
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Badreddine Douzi
- Aix-Marseille University, CNRS, IMM, LCB, Marseille, France
- Aix-Marseille University, CNRS, AFMB, Marseille, France
| | | | - Genevieve Ball
- Aix-Marseille University, CNRS, IMM, LCB, Marseille, France
| | - Romé Voulhoux
- Aix-Marseille University, CNRS, IMM, LCB, Marseille, France
| | - Katrina T. Forest
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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13
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Xu X, Rachedi R, Foglino M, Talla E, Latifi A. Interaction network among factors involved in heterocyst-patterning in cyanobacteria. Mol Genet Genomics 2022; 297:999-1015. [PMID: 35577979 DOI: 10.1007/s00438-022-01902-5] [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: 11/11/2021] [Accepted: 04/16/2022] [Indexed: 10/18/2022]
Abstract
The genetically regulated pattern of heterocyst formation in multicellular cyanobacteria represents the simplest model to address how patterns emerge and are established, the signals that control them, and the regulatory pathways that act downstream. Although numerous factors involved in this process have been identified, the mechanisms of action of many of them remain largely unknown. The aim of this study was to identify specific relationships between 14 factors required for cell differentiation and pattern formation by exploring their putative physical interactions in the cyanobacterium model Nostoc sp. PCC 7120 and by probing their evolutionary conservation and distribution across the cyanobacterial phylum. A bacterial two-hybrid assay indicated that 10 of the 14 factors studied here are engaged in more than one protein-protein interaction. The transcriptional regulator PatB was central in this network as it showed the highest number of binary interactions. A phylum-wide genomic survey of the distribution of these factors in cyanobacteria showed that they are all highly conserved in the genomes of heterocyst-forming strains, with the PatN protein being almost restricted to this clade. Interestingly, eight of the factors that were shown to be capable of protein interactions were identified as key elements in the evolutionary genomics analysis. These data suggest that a network of 12 proteins may play a crucial role in heterocyst development and patterning. Unraveling the physical and functional interactions between these factors during heterocyst development will certainly shed light on the mechanisms underlying pattern establishment in cyanobacteria.
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Affiliation(s)
- Xiaomei Xu
- Aix-Marseille University, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, France, Marseille
| | - Raphaël Rachedi
- Aix-Marseille University, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, France, Marseille
| | - Maryline Foglino
- Aix-Marseille University, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, France, Marseille
| | - Emmanuel Talla
- Aix-Marseille University, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, France, Marseille.
| | - Amel Latifi
- Aix-Marseille University, CNRS, IMM, LCB, Laboratoire de Chimie Bactérienne, France, Marseille.
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14
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Askarian F, Uchiyama S, Masson H, Sørensen HV, Golten O, Bunæs AC, Mekasha S, Røhr ÅK, Kommedal E, Ludviksen JA, Arntzen MØ, Schmidt B, Zurich RH, van Sorge NM, Eijsink VGH, Krengel U, Mollnes TE, Lewis NE, Nizet V, Vaaje-Kolstad G. The lytic polysaccharide monooxygenase CbpD promotes Pseudomonas aeruginosa virulence in systemic infection. Nat Commun 2021; 12:1230. [PMID: 33623002 PMCID: PMC7902821 DOI: 10.1038/s41467-021-21473-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 01/29/2021] [Indexed: 12/20/2022] Open
Abstract
The recently discovered lytic polysaccharide monooxygenases (LPMOs), which cleave polysaccharides by oxidation, have been associated with bacterial virulence, but supporting functional data is scarce. Here we show that CbpD, the LPMO of Pseudomonas aeruginosa, is a chitin-oxidizing virulence factor that promotes survival of the bacterium in human blood. The catalytic activity of CbpD was promoted by azurin and pyocyanin, two redox-active virulence factors also secreted by P. aeruginosa. Homology modeling, molecular dynamics simulations, and small angle X-ray scattering indicated that CbpD is a monomeric tri-modular enzyme with flexible linkers. Deletion of cbpD rendered P. aeruginosa unable to establish a lethal systemic infection, associated with enhanced bacterial clearance in vivo. CbpD-dependent survival of the wild-type bacterium was not attributable to dampening of pro-inflammatory responses by CbpD ex vivo or in vivo. Rather, we found that CbpD attenuates the terminal complement cascade in human serum. Studies with an active site mutant of CbpD indicated that catalytic activity is crucial for virulence function. Finally, profiling of the bacterial and splenic proteomes showed that the lack of this single enzyme resulted in substantial re-organization of the bacterial and host proteomes. LPMOs similar to CbpD occur in other pathogens and may have similar immune evasive functions.
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Affiliation(s)
- Fatemeh Askarian
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
| | - Satoshi Uchiyama
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
| | - Helen Masson
- Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, CA, USA
| | | | - Ole Golten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Anne Cathrine Bunæs
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Sophanit Mekasha
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Åsmund Kjendseth Røhr
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Eirik Kommedal
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | | | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Benjamin Schmidt
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
| | - Raymond H Zurich
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
| | - Nina M van Sorge
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Department of Medical Microbiology and Infection Prevention, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
- Netherlands Reference Laboratory for Bacterial Meningitis, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Tom Eirik Mollnes
- Research Laboratory, Nordland Hospital, Bodø, Norway
- K.G. Jebsen TREC, Faculty of Health Sciences, UiT- The Arctic University of Norway, Tromsø, Norway
- Department of Immunology, Oslo University Hospital, and K.G. Jebsen IRC, University of Oslo, Oslo, Norway
- Center of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Nathan E Lewis
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA
- Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, CA, USA
- Novo Nordisk Foundation Center for Biosustainability at UC San Diego, University of California, San Diego, School of Medicine, La Jolla, CA, USA
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego, La Jolla, CA, USA.
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, CA, USA.
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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15
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Naskar S, Hohl M, Tassinari M, Low HH. The structure and mechanism of the bacterial type II secretion system. Mol Microbiol 2020; 115:412-424. [PMID: 33283907 DOI: 10.1111/mmi.14664] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/03/2020] [Indexed: 12/17/2022]
Abstract
The type II secretion system (T2SS) is a multi-protein complex used by many bacteria to move substrates across their cell membrane. Substrates released into the environment serve as local and long-range effectors that promote nutrient acquisition, biofilm formation, and pathogenicity. In both animals and plants, the T2SS is increasingly recognized as a key driver of virulence. The T2SS spans the bacterial cell envelope and extrudes substrates through an outer membrane secretin channel using a pseudopilus. An inner membrane assembly platform and a cytoplasmic motor controls pseudopilus assembly. This microreview focuses on the structure and mechanism of the T2SS. Advances in cryo-electron microscopy are enabling increasingly elaborate sub-complexes to be resolved. However, key questions remain regarding the mechanism of pseudopilus extension and retraction, and how this is coupled with the choreography of the substrate moving through the secretion system. The T2SS is part of an ancient type IV filament superfamily that may have been present within the last universal common ancestor (LUCA). Overall, mechanistic principles that underlie T2SS function have implication for other closely related systems such as the type IV and tight adherence pilus systems.
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Affiliation(s)
- Souvik Naskar
- Department of Infectious Disease, Imperial College, London, UK
| | - Michael Hohl
- Department of Infectious Disease, Imperial College, London, UK
| | | | - Harry H Low
- Department of Infectious Disease, Imperial College, London, UK
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16
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Silva YRDO, Contreras-Martel C, Macheboeuf P, Dessen A. Bacterial secretins: Mechanisms of assembly and membrane targeting. Protein Sci 2020; 29:893-904. [PMID: 32020694 DOI: 10.1002/pro.3835] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/25/2020] [Accepted: 01/28/2020] [Indexed: 12/20/2022]
Abstract
Secretion systems are employed by bacteria to transport macromolecules across membranes without compromising their integrities. Processes including virulence, colonization, and motility are highly dependent on the secretion of effector molecules toward the immediate cellular environment, and in some cases, into the host cytoplasm. In Type II and Type III secretion systems, as well as in Type IV pili, homomultimeric complexes known as secretins form large pores in the outer bacterial membrane, and the localization and assembly of such 1 MDa molecules often relies on pilotins or accessory proteins. Significant progress has been made toward understanding details of interactions between secretins and their partner proteins using approaches ranging from bacterial genetics to cryo electron microscopy. This review provides an overview of the mode of action of pilotins and accessory proteins for T2SS, T3SS, and T4PS secretins, highlighting recent near-atomic resolution cryo-EM secretin complex structures and underlining the importance of these interactions for secretin functionality.
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Affiliation(s)
- Yuri Rafael de Oliveira Silva
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, São Paulo, Brazil.,Departamento de Genética, Evolução, Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Carlos Contreras-Martel
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Pauline Macheboeuf
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Andréa Dessen
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, São Paulo, Brazil.,Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale (IBS), Grenoble, France
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17
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Ghosal D, Kim KW, Zheng H, Kaplan M, Truchan HK, Lopez AE, McIntire IE, Vogel JP, Cianciotto NP, Jensen GJ. In vivo structure of the Legionella type II secretion system by electron cryotomography. Nat Microbiol 2019; 4:2101-2108. [PMID: 31754273 PMCID: PMC6879910 DOI: 10.1038/s41564-019-0603-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022]
Abstract
The type II secretion system (T2SS) is a multiprotein envelope-spanning assembly that translocates a wide range of virulence factors, enzymes and effectors through the outer membrane of many Gram-negative bacteria1-3. Here, using electron cryotomography and subtomogram averaging methods, we reveal the in vivo structure of an intact T2SS imaged within the human pathogen Legionella pneumophila. Although the T2SS has only limited sequence and component homology with the evolutionarily related type IV pilus (T4P) system4,5, we show that their overall architectures are remarkably similar. Despite similarities, there are also differences, including, for example, that the T2SS-ATPase complex is usually present but disengaged from the inner membrane, the T2SS has a much longer periplasmic vestibule and it has a short-lived flexible pseudopilus. Placing atomic models of the components into our electron cryotomography map produced a complete architectural model of the intact T2SS that provides insights into the structure and function of its components, its position within the cell envelope and the interactions between its different subcomplexes.
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Affiliation(s)
- Debnath Ghosal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Ki Woo Kim
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- School of Ecology and Environmental System, Kyungpook National University, Sangju, Korea
| | - Huaixin Zheng
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
- Department of Immunology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou City, Henan Province, China
| | - Mohammed Kaplan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Hilary K Truchan
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Alberto E Lopez
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Ian E McIntire
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Joseph P Vogel
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
| | - Nicholas P Cianciotto
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Howard Hughes Medical Institute, Pasadena, CA, USA.
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18
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Chernyatina AA, Low HH. Core architecture of a bacterial type II secretion system. Nat Commun 2019; 10:5437. [PMID: 31780649 PMCID: PMC6882859 DOI: 10.1038/s41467-019-13301-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 10/25/2019] [Indexed: 01/01/2023] Open
Abstract
Bacterial type II secretion systems (T2SSs) translocate virulence factors, toxins and enzymes across the cell outer membrane. Here we use negative stain and cryo-electron microscopy to reveal the core architecture of an assembled T2SS from the pathogen Klebsiella pneumoniae. We show that 7 proteins form a ~2.4 MDa complex that spans the cell envelope. The outer membrane complex includes the secretin PulD, with all domains modelled, and the pilotin PulS. The inner membrane assembly platform components PulC, PulE, PulL, PulM and PulN have a relative stoichiometric ratio of 2:1:1:1:1. The PulE ATPase, PulL and PulM combine to form a flexible hexameric hub. Symmetry mismatch between the outer membrane complex and assembly platform is overcome by PulC linkers spanning the periplasm, with PulC HR domains binding independently at the secretin base. Our results show that the T2SS has a highly dynamic modular architecture, with implication for pseudo-pilus assembly and substrate loading.
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Affiliation(s)
| | - Harry H Low
- Department of Life Sciences, Imperial College, London, SW7 2AZ, UK.
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19
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Abstract
Case studies of the evolution of molecular machines remain scarce. One of the most diverse and widespread homologous families of machines is the type IV filament (TFF) superfamily, comprised of type IV pili, type II secretion systems (T2SSs), archaella, and other less-well-characterized families. These families have functions including twitching motility, effector export, rotary propulsion, nutrient uptake, DNA uptake, and even electrical conductance, but it is unclear how such diversity evolved from a common ancestor. In this issue, Denise and colleagues take a significant step toward understanding evolution of the TFF superfamily by determining a global phylogeny and using it to infer an evolutionary pathway. Results reveal that the superfamily predates the divergence of Bacteria and Archaea, and show how duplications, acquisitions, and losses coincide with changes in function. Surprises include that tight adherence (Tad) pili were horizontally acquired from Archaea and that T2SSs were relatively recently repurposed from type IV pili. Results also enable better understanding of the function of the ATPase family that powers the superfamily. The study highlights the role of tinkering by exaptation-the repurposing of pre-existing functions for new roles-in the diversification of molecular machines.
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Affiliation(s)
- Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
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20
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Abstract
The type II secretion system (T2SS) delivers toxins and a range of hydrolytic enzymes, including proteases, lipases, and carbohydrate-active enzymes, to the cell surface or extracellular space of Gram-negative bacteria. Its contribution to survival of both extracellular and intracellular pathogens as well as environmental species of proteobacteria is evident. This dynamic, multicomponent machinery spans the entire cell envelope and consists of a cytoplasmic ATPase, several inner membrane proteins, a periplasmic pseudopilus, and a secretin pore embedded in the outer membrane. Despite the trans-envelope configuration of the T2S nanomachine, proteins to be secreted engage with the system first once they enter the periplasmic compartment via the Sec or TAT export system. Thus, the T2SS is specifically dedicated to their outer membrane translocation. The many sequence and structural similarities between the T2SS and type IV pili suggest a common origin and argue for a pilus-mediated mechanism of secretion. This minireview describes the structures, functions, and interactions of the individual T2SS components and the general architecture of the assembled T2SS machinery and briefly summarizes the transport and function of a growing list of T2SS exoproteins. Recent advances in cryo-electron microscopy, which have led to an increased understanding of the structure-function relationship of the secretin channel and the pseudopilus, are emphasized.
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21
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White RC, Cianciotto NP. Assessing the impact, genomics and evolution of type II secretion across a large, medically important genus: the Legionella type II secretion paradigm. Microb Genom 2019; 5. [PMID: 31166887 PMCID: PMC6617341 DOI: 10.1099/mgen.0.000273] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The type II secretion system (T2SS) plays a major role in promoting bacterial survival in the environment and in human hosts. One of the best characterized T2SS is that of Legionella pneumophila, the agent of Legionnaires’ disease. Secreting at least 25 proteins, including degradative enzymes, eukaryotic-like proteins and novel effectors, this T2SS contributes to the ability of L. pneumophila to grow at low temperatures, infect amoebal and macrophage hosts, damage lung tissue, evade the immune system, and undergo sliding motility. The genes encoding the T2SS are conserved across the genus Legionella, which includes 62 species and >30 pathogens in addition to L. pneumophila. The vast majority of effectors associated with L. pneumophila are shared by a large number of Legionella species, hinting at a critical role for them in the ecology of Legionella as a whole. However, no other species has the same repertoire as L. pneumophila, with, as a general rule, phylogenetically more closely related species sharing similar sets of effectors. T2SS effectors that are involved in infection of a eukaryotic host(s) are more prevalent throughout Legionella, indicating that they are under stronger selective pressure. The Legionella T2SS apparatus is closest to that of Aquicella (another parasite of amoebae), and a significant number of L. pneumophila effectors have their closest homologues in Aquicella. Thus, the T2SS of L. pneumophila probably originated within the order Legionellales, with some of its effectors having arisen within that Aquicella-like progenitor, while other effectors derived from the amoebal host, mimiviruses, fungi and less closely related bacteria.
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Affiliation(s)
- Richard C White
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Nicholas P Cianciotto
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
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