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Valenzuela-Gómez F, Arechaga I, Cabezón E. Nanopore sensing reveals a preferential pathway for the co-translocational unfolding of a conjugative relaxase-DNA complex. Nucleic Acids Res 2023; 51:6857-6869. [PMID: 37264907 PMCID: PMC10359608 DOI: 10.1093/nar/gkad492] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/05/2023] [Accepted: 05/26/2023] [Indexed: 06/03/2023] Open
Abstract
Bacterial conjugation is the main mechanism for the dissemination of antibiotic resistance genes. A single DNA strand of the conjugative plasmid is transferred across bacterial membranes covalently bound to a large multi-domain protein, named relaxase, which must be unfolded to traverse the secretion channel. Two tyrosine residues of the relaxase (Y18 and Y26 in relaxase TrwC) play an important role in the processing of conjugative DNA. We have used nanopore technology to uncover the unfolding states that take place during translocation of the relaxase-DNA complex. We observed that the relaxase unfolding pathway depends on the tyrosine residue involved in conjugative DNA binding. Transfer of the nucleoprotein complex is faster when DNA is bound to residue Y18. This is the first time in which a protein-DNA complex that is naturally translocated through bacterial membranes has been analyzed by nanopore sensing, opening new horizons to apply this technology to study protein secretion.
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Affiliation(s)
- Fernando Valenzuela-Gómez
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria- CSIC, 39011 Santander, Spain
| | - Ignacio Arechaga
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria- CSIC, 39011 Santander, Spain
| | - Elena Cabezón
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria- CSIC, 39011 Santander, Spain
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2
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Woodbury DJ, Whitt EC, Coffman RE. A review of TNP-ATP in protein binding studies: benefits and pitfalls. BIOPHYSICAL REPORTS 2021; 1:100012. [PMID: 36425312 PMCID: PMC9680771 DOI: 10.1016/j.bpr.2021.100012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 08/03/2021] [Indexed: 06/16/2023]
Abstract
We review 50 years of use of 2',3'-O-trinitrophenyl (TNP)-ATP, a fluorescently tagged ATP analog. It has been extensively used to detect binding interactions of ATP to proteins and to measure parameters of those interactions such as the dissociation constant, Kd, or inhibitor dissociation constant, Ki. TNP-ATP has also found use in other applications, for example, as a fluorescence marker in microscopy, as a FRET pair, or as an antagonist (e.g., of P2X receptors). However, its use in protein binding studies has limitations because the TNP moiety often enhances binding affinity, and the fluorescence changes that occur with binding can be masked or mimicked in unexpected ways. The goal of this review is to provide a clear perspective of the pros and cons of using TNP-ATP to allow for better experimental design and less ambiguous data in future experiments using TNP-ATP and other TNP nucleotides.
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Affiliation(s)
- Dixon J. Woodbury
- Department of Cell Biology and Physiology
- Neuroscience Center, Brigham Young University, Provo, Utah
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3
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Spectrophotometric Assays to Quantify the Activity of T4SS ATPases. Methods Mol Biol 2019. [PMID: 31584160 DOI: 10.1007/978-1-4939-9877-7_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Biogenesis of T4SS apparatus and substrate transport require energy. Conjugative T4SS have three ATPases that enable DNA processing and transport of the nucleoprotein complex to the recipient cell. In the conjugative plasmid R388, these ATPases are named TrwB, TrwK, and TrwD. Here, three different spectrophotometric assays to measure the enzymatic properties of these ATPases are described. The choice of the assay will depend on the specific requirements of each enzyme.
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4
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García-Cazorla Y, Getino M, Sanabria-Ríos DJ, Carballeira NM, de la Cruz F, Arechaga I, Cabezón E. Conjugation inhibitors compete with palmitic acid for binding to the conjugative traffic ATPase TrwD, providing a mechanism to inhibit bacterial conjugation. J Biol Chem 2018; 293:16923-16930. [PMID: 30201608 DOI: 10.1074/jbc.ra118.004716] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 09/04/2018] [Indexed: 01/14/2023] Open
Abstract
Bacterial conjugation is a key mechanism by which bacteria acquire antibiotic resistance. Therefore, conjugation inhibitors (COINs) are promising compounds in the fight against the spread of antibiotic resistance genes among bacteria. Unsaturated fatty acids (uFAs) and alkynoic fatty acid derivatives, such as 2-hexadecanoic acid (2-HDA), have been reported previously as being effective COINs. The traffic ATPase TrwD, a VirB11 homolog in plasmid R388, is the molecular target of these compounds, which likely affect binding of TrwD to bacterial membranes. In this work, we demonstrate that COINs are abundantly incorporated into Escherichia coli membranes, replacing palmitic acid as the major component of the membrane. We also show that TrwD binds palmitic acid, thus facilitating its interaction with the membrane. Our findings also suggest that COINs bind TrwD at a site that is otherwise occupied by palmitic acid. Accordingly, molecular docking predictions with palmitic acid indicated that it shares the same binding site as uFAs and 2-HDA, although it differs in the contacts involved in this interaction. We also identified 2-bromopalmitic acid, a palmitate analog that inhibits many membrane-associated enzymes, as a compound that effectively reduces TrwD ATPase activity and bacterial conjugation. Moreover, we demonstrate that 2-bromopalmitic and palmitic acids both compete for the same binding site in TrwD. Altogether, these detailed findings open up a new avenue in the search for effective synthetic inhibitors of bacterial conjugation, which may be pivotal for combating multidrug-resistant bacteria.
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Affiliation(s)
- Yolanda García-Cazorla
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, 39011 Santander, Spain
| | - María Getino
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, 39011 Santander, Spain
| | - David J Sanabria-Ríos
- the Inter-American University of Puerto Rico, Metropolitan Campus, Faculty of Science and Technology, San Juan, Puerto Rico 00919, and
| | - Néstor M Carballeira
- the Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00925
| | - Fernando de la Cruz
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, 39011 Santander, Spain
| | - Ignacio Arechaga
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, 39011 Santander, Spain,
| | - Elena Cabezón
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria, Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, 39011 Santander, Spain,
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5
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Kim SH, Lee MH, Park M, Woo HJ, Kim YS, Tharmalingam N, Seo WD, Kim JB. Regulatory Effects of Black Rice Extract on Helicobacter pylori Infection-Induced Apoptosis. Mol Nutr Food Res 2017; 62. [PMID: 29035012 DOI: 10.1002/mnfr.201700586] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/28/2017] [Indexed: 12/12/2022]
Abstract
SCOPE Black rice extract (BRE) contains cyanidin 3-O-glucoside (C3G), an anthocyanin, as the major component. In this study, we found that BRE inhibits the mRNA and protein expression of genes encoding cytotoxin-associated protein A (cagA) and vacuolating protein A (vacA) in Helicobacter pylori 60190 strain. METHODS AND RESULTS We performed RT-PCR and western blotting to show that BRE inhibits the mRNA and protein expression of SecA. Because SecA is involved in VacA export in bacteria, our result suggests a positive correlation between BRE-induced inhibition of secA expression and VacA secretion. Further, we perform MTT assay and flow cytometry to show that BRE decreases the apoptosis of H. pylori-infected KATO III cells. Finally, we perform western blotting to show that the cell-protective effect of BRE is associated with decreased levels of active proapoptotic proteins caspases and PARP and increased levels of antiapoptotic proteins survivin and XIAP in H. pylori-infected cells. CONCLUSION Thus, our results indicate that BRE acts as a potent inhibitor of the biogenesis of H. pylori virulence proteins and decreases the apoptosis of H. pylori-infected cells. Moreover, our results suggest that BRE can be used to exert beneficial effects in patients with gastroduodenal diseases caused by H. pylori.
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Affiliation(s)
- Sa-Hyun Kim
- Department of Clinical Laboratory Science, Semyung University, Jecheon, Republic of Korea
| | - Min Ho Lee
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
| | - Min Park
- Department of Biomedical Laboratory Science, Daekyeung University, Gyeongsan, Republic of Korea
| | - Hyun Jun Woo
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
| | - Yoon Suk Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
| | - Nagendran Tharmalingam
- Division of Infectious Diseases, Department of Medicine, Rhode Island Hospital, Alpert Medical School of Brown University, Providence, RI, USA
| | - Woo-Duck Seo
- Crop Foundation Division, National Institute of Crop Science, Jeollabuk-do, Republic of Korea
| | - Jong-Bae Kim
- Department of Biomedical Laboratory Science, College of Health Sciences, Yonsei University, Wonju, Republic of Korea
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6
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Cabezón E, de la Cruz F, Arechaga I. Conjugation Inhibitors and Their Potential Use to Prevent Dissemination of Antibiotic Resistance Genes in Bacteria. Front Microbiol 2017; 8:2329. [PMID: 29255449 PMCID: PMC5723004 DOI: 10.3389/fmicb.2017.02329] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 11/13/2017] [Indexed: 11/17/2022] Open
Abstract
Antibiotic resistance has become one of the most challenging problems in health care. Bacteria conjugation is one of the main mechanisms whereby bacteria become resistant to antibiotics. Therefore, the search for specific conjugation inhibitors (COINs) is of interest in the fight against the spread of antibiotic resistances in a variety of laboratory and natural environments. Several compounds, discovered as COINs, are promising candidates in the fight against plasmid dissemination. In this review, we survey the effectiveness and toxicity of the most relevant compounds. Particular emphasis has been placed on unsaturated fatty acid derivatives, as they have been shown to be efficient in preventing plasmid invasiveness in bacterial populations. Biochemical and structural studies have provided insights concerning their potential molecular targets and inhibitory mechanisms. These findings open a new avenue in the search of new and more effective synthetic inhibitors. In this pursuit, the use of structure-based drug design methods will be of great importance for the screening of ligands and binding sites of putative targets.
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Affiliation(s)
- Elena Cabezón
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria and Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - Fernando de la Cruz
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria and Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - Ignacio Arechaga
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria and Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
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7
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Ripoll-Rozada J, García-Cazorla Y, Getino M, Machón C, Sanabria-Ríos D, de la Cruz F, Cabezón E, Arechaga I. Type IV traffic ATPase TrwD as molecular target to inhibit bacterial conjugation. Mol Microbiol 2016; 100:912-21. [PMID: 26915347 DOI: 10.1111/mmi.13359] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bacterial conjugation is the main mechanism responsible for the dissemination of antibiotic resistance genes. Hence, the search for specific conjugation inhibitors is paramount in the fight against the spread of these genes. In this pursuit, unsaturated fatty acids have been found to specifically inhibit bacterial conjugation. Despite the growing interest on these compounds, their mode of action and their specific target remain unknown. Here, we identified TrwD, a Type IV secretion traffic ATPase, as the molecular target for fatty acid-mediated inhibition of conjugation. Moreover, 2-alkynoic fatty acids, which are also potent inhibitors of bacterial conjugation, are also powerful inhibitors of the ATPase activity of TrwD. Characterization of the kinetic parameters of ATPase inhibition has led us to identify the catalytic mechanism by which fatty acids exert their activity. These results open a new avenue for the rational design of inhibitors of bacterial conjugation in the fight against the dissemination of antibiotic resistance genes.
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Affiliation(s)
- Jorge Ripoll-Rozada
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - Yolanda García-Cazorla
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - María Getino
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - Cristina Machón
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - David Sanabria-Ríos
- Inter American University of Puerto Rico-Metropolitan Campus, Faculty of Science and Technology, San Juan, Puerto Rico
| | - Fernando de la Cruz
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - Elena Cabezón
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
| | - Ignacio Arechaga
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC, Santander, Spain
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8
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Abstract
Type IV secretion systems (T4SSs) are large multisubunit translocons, found in both gram-negative and gram-positive bacteria and in some archaea. These systems transport a diverse array of substrates from DNA and protein-DNA complexes to proteins, and play fundamental roles in both bacterial pathogenesis and bacterial adaptation to the cellular milieu in which bacteria live. This review describes the various biochemical and structural advances made toward understanding the biogenesis, architecture, and function of T4SSs.
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Affiliation(s)
- Vidya Chandran Darbari
- Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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9
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Shariq M, Kumar N, Kumari R, Kumar A, Subbarao N, Mukhopadhyay G. Biochemical Analysis of CagE: A VirB4 Homologue of Helicobacter pylori Cag-T4SS. PLoS One 2015; 10:e0142606. [PMID: 26565397 PMCID: PMC4643968 DOI: 10.1371/journal.pone.0142606] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 10/23/2015] [Indexed: 12/30/2022] Open
Abstract
Helicobacter pylori are among the most successful human pathogens that harbour a distinct genomic segment called cag Pathogenicity Island (cag-PAI). This genomic segment codes for a type IV secretion system (Cag-T4SS) related to the prototypical VirB/D4 system of Agrobacterium tumefaciens (Ag), a plant pathogen. Some of the components of Cag-T4SS share homology to that of VirB proteins including putative energy providing CagE (HP0544), the largest VirB4 homologue. In Ag, VirB4 is required for the assembly of the system, substrate translocation and pilus formation, however, very little is known about CagE. Here we have characterised the protein biochemically, genetically, and microscopically and report that CagE is an inner membrane associated active NTPase and has multiple interacting partners including the inner membrane proteins CagV and Cagβ. Through CagV it is connected to the outer membrane sub-complex proteins. Stability of CagE is not dependent on several of the cag-PAI proteins tested. However, localisation and stability of the pilus associated CagI, CagL and surface associated CagH are affected in its absence. Stability of the inner membrane associated energetic component Cagβ, a VirD4 homologue seems to be partially affected in its absence. Additionally, CagA failed to cross the membrane barriers in its absence and no IL-8 induction is observed under infection condition. These results thus suggest the importance of CagE in Cag-T4SS functions. In future it may help in deciphering the mechanism of substrate translocation by the system.
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Affiliation(s)
- Mohd Shariq
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- * E-mail: (MS); (GM)
| | - Navin Kumar
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Rajesh Kumari
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
| | - Amarjeet Kumar
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Naidu Subbarao
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Gauranga Mukhopadhyay
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, India
- * E-mail: (MS); (GM)
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10
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Cabezón E, Ripoll-Rozada J, Peña A, de la Cruz F, Arechaga I. Towards an integrated model of bacterial conjugation. FEMS Microbiol Rev 2014; 39:81-95. [PMID: 25154632 DOI: 10.1111/1574-6976.12085] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Bacterial conjugation is one of the main mechanisms for horizontal gene transfer. It constitutes a key element in the dissemination of antibiotic resistance and virulence genes to human pathogenic bacteria. DNA transfer is mediated by a membrane-associated macromolecular machinery called Type IV secretion system (T4SS). T4SSs are involved not only in bacterial conjugation but also in the transport of virulence factors by pathogenic bacteria. Thus, the search for specific inhibitors of different T4SS components opens a novel approach to restrict plasmid dissemination. This review highlights recent biochemical and structural findings that shed new light on the molecular mechanisms of DNA and protein transport by T4SS. Based on these data, a model for pilus biogenesis and substrate transfer in conjugative systems is proposed. This model provides a renewed view of the mechanism that might help to envisage new strategies to curb the threating expansion of antibiotic resistance.
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Affiliation(s)
- Elena Cabezón
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Jorge Ripoll-Rozada
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Alejandro Peña
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Fernando de la Cruz
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
| | - Ignacio Arechaga
- Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC, (Universidad de Cantabria, CSIC) Santander, Spain
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11
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Kim SH, Woo H, Park M, Rhee KJ, Moon C, Lee D, Seo WD, Kim JB. Cyanidin 3-O-glucoside reduces Helicobacter pylori VacA-induced cell death of gastric KATO III cells through inhibition of the SecA pathway. Int J Med Sci 2014; 11:742-7. [PMID: 24904230 PMCID: PMC4045794 DOI: 10.7150/ijms.7167] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 04/21/2014] [Indexed: 02/06/2023] Open
Abstract
Two key virulence factors of Helicobacter pylori are the secreted virulent proteins of vacuolating toxin A (VacA) and cytotoxin associated protein A (CagA) which lead to damages of gastric epithelial cells. We previously identified that the cyanidin 3-O-glucoside (C3G) inhibits the secretion of both VacA and CagA. In the current report, we show that C3G inhibits VacA secretion in a dose-dependent manner by inhibiting secretion system subunit protein A (SecA) synthesis. As SecA is involved in translocation of bacterial proteins, we predicted that inhibition of the SecA pathway by C3G should decrease H. pylori-induced cell death. To test this hypothesis, the human gastric cell line KATO III cells were co-cultured with H. pylori 60190 (VacA(+)/CagA(+)) and C3G. We found that C3G treatment caused a decrease in activation of the pro-apoptotic proteins caspase-3/-8 in H. pylori-infected cells leading to a decrease in cell death. Our data suggest that consumption of foods containing anthocyanin may be beneficial in reducing cell damage due to H. pylori infection.
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Affiliation(s)
- Sa-Hyun Kim
- 1. Department of Clinical Laboratory Science, Semyung University, Jaecheon 390-711, Republic of Korea
| | - Hyunjun Woo
- 2. Department of Biomedical Laboratory Science, College of Health Science, Yonsei University, Wonju 220-710, Republic of Korea
| | - Min Park
- 2. Department of Biomedical Laboratory Science, College of Health Science, Yonsei University, Wonju 220-710, Republic of Korea
| | - Ki-Jong Rhee
- 2. Department of Biomedical Laboratory Science, College of Health Science, Yonsei University, Wonju 220-710, Republic of Korea
| | - Cheol Moon
- 1. Department of Clinical Laboratory Science, Semyung University, Jaecheon 390-711, Republic of Korea
| | - Dongsup Lee
- 3. Department of Clinical Laboratory Science, Hyegeon College, Hongseong 350-702, Republic of Korea
| | - Woo Duck Seo
- 4. Department of Functional Crops, National Institute of Crop Science, Rural Development Administration, Miryang 627-803, Republic of Korea
| | - Jong Bae Kim
- 2. Department of Biomedical Laboratory Science, College of Health Science, Yonsei University, Wonju 220-710, Republic of Korea
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12
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Structural organisation of the type IV secretion systems. Curr Opin Microbiol 2013; 17:24-31. [PMID: 24581689 PMCID: PMC3969286 DOI: 10.1016/j.mib.2013.11.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 11/06/2013] [Accepted: 11/07/2013] [Indexed: 02/04/2023]
Abstract
Type IV secretion systems are nanomachines that transport substrates through bacterial membranes. Structures of components obtained by crystallography are presented. Higher resolution core complex structures revealed localisations of protein components. Docking of known and modelled atomic structures uncovers interactions between components.
Type IV secretion (T4S) systems are large dynamic nanomachines that transport DNAs and/or proteins through the membranes of bacteria. Because of their complexity and multi-protein organisation, T4S systems have been extremely challenging to study structurally. However in the past five years significant milestones have been achieved by X-ray crystallography and cryo-electron microscopy. This review describes some of the more recent advances: the structures of some of the protein components of the T4S systems and the complete core complex structure that was determined using electron microscopy.
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13
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Gao D, Bian X, Guo M, Wang J, Zhang X. Identification and characterization of the biochemical function of Agrobacterium T-complex-recruiting protein Atu5117. FEBS J 2013; 280:4865-75. [PMID: 23902381 DOI: 10.1111/febs.12460] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 07/24/2013] [Accepted: 07/26/2013] [Indexed: 01/19/2023]
Abstract
Atu5117 from Agrobacterium tumefaciens is a highly conserved protein with a putative nucleotidyltransferase domain in its N-terminal region and a putative higher eukaryotes and prokaryotes nucleotide-binding domain in its C-terminal region. This protein has been shown to be a T-complex-recruiting protein that can recruit T-complex from the cytosol to the polar VirB/D4 type IV secretion system (T4SS). However, the biochemical function of Atu5117 is still unknown. Here, we show that Atu5117 is a (d)NTPase. Although no proteins with nucleotidyltransferase and higher eukaryotes and prokaryotes nucleotide-binding domains were identified as (d)NTPases, Atu5117 was able to convert all eight canonical NTPs and dNTPs to NDP, dNDP and inorganic phosphate in vitro, and required Mg(2+) for its (d)NTPase activity. The kinetic parameters of Atu5117 (d)NTPase for eight substrates were characterized. Kinetic data showed that Atu5117 (d)NTPase preferred ATP as its substrate. The optimal conditions for (d)NTPase activity of Atu5117 were very similar to those required for Agrobacterium tumorigenesis. The kinetic parameters of (d)NTPase of Atu5117 for all four canonical NTPs were in the same orders of magnitude as the kinetic parameters of the ATPases identified in some components of the VirB/D4 T4SS. These results suggest that Atu5117 might function as an energizer to recruit T-complex to the T4SS transport site.
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Affiliation(s)
- Diankun Gao
- College of Bioscience and Biotechnology, Yangzhou University, China
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14
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Abstract
Secretion of effectors across bacterial membranes is usually mediated by large multisubunit complexes. In most cases, the secreted effectors are virulent factors normally associated to pathogenic diseases. The biogenesis of these secretion systems and the transport of the effectors are processes that require energy. This energy could be directly obtained by using the proton motive force, but in most cases the energy associated to these processes is derived from ATP hydrolysis. Here, a description of the machineries involved in generating the energy required for system biogenesis and substrate transport by type II, III and IV secretion systems is provided, with special emphasis on highlighting the structural similarities and evolutionary relationships among the secretion ATPases.
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Affiliation(s)
- Alejandro Peña
- Departamento de Biología Molecular, Universidad de Cantabria, UC-CSIC-SODERCAN, Santander, Spain
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15
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Functional interactions of VirB11 traffic ATPases with VirB4 and VirD4 molecular motors in type IV secretion systems. J Bacteriol 2013; 195:4195-201. [PMID: 23852869 DOI: 10.1128/jb.00437-13] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pilus biogenesis and substrate transport by type IV secretion systems require energy, which is provided by three molecular motors localized at the base of the secretion channel. One of these motors, VirB11, belongs to the superfamily of traffic ATPases, which includes members of the type II secretion system and the type IV pilus and archaeal flagellar assembly apparatus. Here, we report the functional interactions between TrwD, the VirB11 homolog of the conjugative plasmid R388, and TrwK and TrwB, the motors involved in pilus biogenesis and DNA transport, respectively. Although these interactions remained standing upon replacement of the traffic ATPase by a homolog from a phylogenetically related conjugative system, namely, TraG of plasmid pKM101, this homolog could not replace the TrwD function for DNA transfer. This result suggests that VirB11 works as a switch between pilus biogenesis and DNA transport and reinforces a mechanistic model in which VirB11 proteins act as traffic ATPases by regulating both events in type IV secretion systems.
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Abstract
Bacteria have evolved several secretion machineries to bring about transport of various virulence factors, nutrients, nucleic acids and cell-surface appendages that are essential for their pathogenesis. T4S (Type IV secretion) systems are versatile secretion systems found in various Gram-negative and Gram-positive bacteria and in few archaea. They are large multisubunit translocons secreting a diverse array of substrates varying in size and nature from monomeric proteins to nucleoprotein complexes. T4S systems have evolved from conjugation machineries and are implicated in antibiotic resistance gene transfer and transport of virulence factors in Legionella pneumophila causing Legionnaires’ disease, Brucella suis causing brucellosis and Helicobacter pylori causing gastroduodenal diseases. The best-studied are the Agrobacterium tumefaciens VirB/D4 and the Escherichia coli plasmid pKM101 T4S systems. Recent structural advances revealing the cryo-EM (electron microscopy) structure of the core translocation assembly and high-resolution structure of the outer-membrane pore of T4S systems have made paradigm shifts in the understanding of T4S systems. The present paper reviews the advances made in biochemical and structural studies and summarizes our current understanding of the molecular architecture of this mega-assembly.
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Peña A, Matilla I, Martín-Benito J, Valpuesta JM, Carrascosa JL, de la Cruz F, Cabezón E, Arechaga I. The hexameric structure of a conjugative VirB4 protein ATPase provides new insights for a functional and phylogenetic relationship with DNA translocases. J Biol Chem 2012; 287:39925-32. [PMID: 23035111 DOI: 10.1074/jbc.m112.413849] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
VirB4 proteins are ATPases essential for pilus biogenesis and protein transport in type IV secretion systems. These proteins contain a motor domain that shares structural similarities with the motor domains of DNA translocases, such as the VirD4/TrwB conjugative coupling proteins and the chromosome segregation pump FtsK. Here, we report the three-dimensional structure of full-length TrwK, the VirB4 homologue in the conjugative plasmid R388, determined by single-particle electron microscopy. The structure consists of a hexameric double ring with a barrel-shaped structure. The C-terminal half of VirB4 proteins shares a striking structural similarity with the DNA translocase TrwB. Docking the atomic coordinates of the crystal structures of TrwB and FtsK into the EM map revealed a better fit for FtsK. Interestingly, we have found that like TrwB, TrwK is able to bind DNA with a higher affinity for G4 quadruplex structures than for single-stranded DNA. Furthermore, TrwK exerts a dominant negative effect on the ATPase activity of TrwB, which reflects an interaction between the two proteins. Our studies provide new insights into the structure-function relationship and the evolution of these DNA and protein translocases.
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Affiliation(s)
- Alejandro Peña
- Departamento de Biología Molecular, Universidad de Cantabria, and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), UC-CSIC-SODERCAN, Santander, Spain
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Kim SH, Park M, Woo H, Tharmalingam N, Lee G, Rhee KJ, Eom YB, Han SI, Seo WD, Kim JB. Inhibitory effects of anthocyanins on secretion of Helicobacter pylori CagA and VacA toxins. Int J Med Sci 2012; 9:838-42. [PMID: 23155357 PMCID: PMC3498748 DOI: 10.7150/ijms.5094] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 10/25/2012] [Indexed: 01/20/2023] Open
Abstract
Anthocyanins have been studied as potential antimicrobial agents against Helicobacter pylori. We investigated whether the biosynthesis and secretion of cytotoxin-associated protein A (CagA) and vacuolating cytotoxin A (VacA) could be suppressed by anthocyanin treatment in vitro. H. pylori reference strain 60190 (CagA(+)/VacA(+)) was used in this study to investigate the inhibitory effects of anthocyanins; cyanidin 3-O-glucoside (C3G), peonidin 3-O-glucoside (Peo3G), pelargonidin 3-O-glucoside (Pel3G), and malvidin 3-O-glucoside (M3G) on expression and secretion of H. pylori toxins. Anthocyanins were added to bacterial cultures and Western blotting was used to determine secretion of CagA and VacA. Among them, we found that C3G inhibited secretion of CagA and VacA resulting in intracellular accumulation of CagA and VacA. C3G had no effect on cagA and vacA expression but suppressed secA transcription. As SecA is involved in translocation of bacterial proteins, the down-regulation of secA expression by C3G offers a mechanistic explanation for the inhibition of toxin secretion. To our knowledge, this is the first report suggesting that C3G inhibits secretion of the H. pylori toxins CagA and VacA via suppression of secA transcription.
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Affiliation(s)
- Sa-Hyun Kim
- Department of Biomedical Laboratory Science, College of Health Science, Yonsei University, Wonju, Republic of Korea
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