1
|
Daveri A, Benigno V, van der Meer JR. Characterization of an atypical but widespread type IV secretion system for transfer of the integrative and conjugative element (ICEclc) in Pseudomonas putida. Nucleic Acids Res 2023; 51:2345-2362. [PMID: 36727472 PMCID: PMC10018362 DOI: 10.1093/nar/gkad024] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 12/23/2022] [Accepted: 01/26/2023] [Indexed: 02/03/2023] Open
Abstract
Conjugation of DNA relies on multicomponent protein complexes bridging two bacterial cytoplasmic compartments. Whereas plasmid conjugation systems have been well documented, those of integrative and conjugative elements (ICEs) have remained poorly studied. We characterize here the conjugation system of the ICEclc element in Pseudomonas putida UWC1 that is a model for a widely distributed family of ICEs. By in frame deletion and complementation, we show the importance on ICE transfer of 22 genes in a 20-kb conserved ICE region. Protein comparisons recognized seven homologs to plasmid type IV secretion system components, another six homologs to frequent accessory proteins, and the rest without detectable counterparts. Stationary phase imaging of P. putida ICEclc with in-frame fluorescent protein fusions to predicted type IV components showed transfer-competent cell subpopulations with multiple fluorescent foci, largely overlapping in dual-labeled subcomponents, which is suggestive for multiple conjugation complexes per cell. Cross-dependencies between subcomponents in ICE-type IV secretion system assembly were revealed by quantitative foci image analysis in a variety of ICEclc mutant backgrounds. In conclusion, the ICEclc family presents an evolutionary distinct type IV conjugative system with transfer competent cells specialized in efficient transfer.
Collapse
Affiliation(s)
- Andrea Daveri
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Valentina Benigno
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | | |
Collapse
|
2
|
The functional coupling between restriction and DNA phosphorothioate modification systems underlying the DndFGH restriction complex. Nat Catal 2022. [DOI: 10.1038/s41929-022-00884-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
3
|
Nowak KP, Sobolewska-Ruta A, Jagiełło A, Bierczyńska-Krzysik A, Kierył P, Wawrzyniak P. Molecular and Functional Characterization of MobK Protein-A Novel-Type Relaxase Involved in Mobilization for Conjugational Transfer of Klebsiella pneumoniae Plasmid pIGRK. Int J Mol Sci 2021; 22:5152. [PMID: 34068033 PMCID: PMC8152469 DOI: 10.3390/ijms22105152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/07/2021] [Accepted: 05/09/2021] [Indexed: 02/01/2023] Open
Abstract
Conjugation, besides transformation and transduction, is one of the main mechanisms of horizontal transmission of genetic information among bacteria. Conjugational transfer, due to its essential role in shaping bacterial genomes and spreading of antibiotics resistance genes, has been widely studied for more than 70 years. However, new and intriguing facts concerning the molecular basis of this process are still being revealed. Most recently, a novel family of conjugative relaxases (Mob proteins) was distinguished. The characteristic feature of these proteins is that they are not related to any of Mobs described so far. Instead of this, they share significant similarity to tyrosine recombinases. In this study MobK-a tyrosine recombinase-like Mob protein, encoded by pIGRK cryptic plasmid from the Klebsiella pneumoniae clinical strain, was characterized. This study revealed that MobK is a site-specific nuclease and its relaxase activity is dependent on both a conserved catalytic tyrosine residue (Y179) that is characteristic of tyrosine recombinases and the presence of Mg2+ divalent cations. The pIGRK minimal origin of transfer sequence (oriT) was also characterized. This is one of the first reports presenting tyrosine recombinase-like conjugative relaxase protein. It also demonstrates that MobK is a convenient model for studying this new protein family.
Collapse
Affiliation(s)
- Katarzyna Paulina Nowak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland;
- Department of Biomedical Technology, Cosmetics Chemicals and Electrochemistry, Łukasiewicz Research Network—Industrial Chemistry Institute, Rydygiera 8, 01-793 Warsaw, Poland; (A.S.-R.); (A.J.); (A.B.-K.); (P.K.)
| | - Agnieszka Sobolewska-Ruta
- Department of Biomedical Technology, Cosmetics Chemicals and Electrochemistry, Łukasiewicz Research Network—Industrial Chemistry Institute, Rydygiera 8, 01-793 Warsaw, Poland; (A.S.-R.); (A.J.); (A.B.-K.); (P.K.)
| | - Agata Jagiełło
- Department of Biomedical Technology, Cosmetics Chemicals and Electrochemistry, Łukasiewicz Research Network—Industrial Chemistry Institute, Rydygiera 8, 01-793 Warsaw, Poland; (A.S.-R.); (A.J.); (A.B.-K.); (P.K.)
- Central Forensic Laboratory of the Police, Biology Department, Iwicka 14, 00-735 Warsaw, Poland
| | - Anna Bierczyńska-Krzysik
- Department of Biomedical Technology, Cosmetics Chemicals and Electrochemistry, Łukasiewicz Research Network—Industrial Chemistry Institute, Rydygiera 8, 01-793 Warsaw, Poland; (A.S.-R.); (A.J.); (A.B.-K.); (P.K.)
- Curiosity Diagnostics Sp. z o.o., Duchnicka 3, Building 16, Entrance A, 01-796 Warsaw, Poland
| | - Piotr Kierył
- Department of Biomedical Technology, Cosmetics Chemicals and Electrochemistry, Łukasiewicz Research Network—Industrial Chemistry Institute, Rydygiera 8, 01-793 Warsaw, Poland; (A.S.-R.); (A.J.); (A.B.-K.); (P.K.)
| | - Paweł Wawrzyniak
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland;
- Department of Biomedical Technology, Cosmetics Chemicals and Electrochemistry, Łukasiewicz Research Network—Industrial Chemistry Institute, Rydygiera 8, 01-793 Warsaw, Poland; (A.S.-R.); (A.J.); (A.B.-K.); (P.K.)
| |
Collapse
|
4
|
Jenkins T, Northall SJ, Ptchelkine D, Lever R, Cubbon A, Betts H, Taresco V, Cooper CDO, McHugh PJ, Soultanas P, Bolt EL. The HelQ human DNA repair helicase utilizes a PWI-like domain for DNA loading through interaction with RPA, triggering DNA unwinding by the HelQ helicase core. NAR Cancer 2021; 3:zcaa043. [PMID: 34316696 PMCID: PMC8210318 DOI: 10.1093/narcan/zcaa043] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/30/2020] [Accepted: 12/16/2020] [Indexed: 01/04/2023] Open
Abstract
Genome instability is a characteristic enabling factor for carcinogenesis. HelQ helicase is a component of human DNA maintenance systems that prevent or reverse genome instability arising during DNA replication. Here, we provide details of the molecular mechanisms that underpin HelQ function-its recruitment onto ssDNA through interaction with replication protein A (RPA), and subsequent translocation of HelQ along ssDNA. We describe for the first time a functional role for the non-catalytic N-terminal region of HelQ, by identifying and characterizing its PWI-like domain. We present evidence that this domain of HelQ mediates interaction with RPA that orchestrates loading of the helicase domains onto ssDNA. Once HelQ is loaded onto the ssDNA, ATP-Mg2+ binding in the catalytic site activates the helicase core and triggers translocation along ssDNA as a dimer. Furthermore, we identify HelQ-ssDNA interactions that are critical for the translocation mechanism. Our data are novel and detailed insights into the mechanisms of HelQ function relevant for understanding how human cells avoid genome instability provoking cancers, and also how cells can gain resistance to treatments that rely on DNA crosslinking agents.
Collapse
Affiliation(s)
- Tabitha Jenkins
- School of Life Sciences, The University of Nottingham, NG7 2UH, Nottingham, UK
| | - Sarah J Northall
- School of Life Sciences, The University of Nottingham, NG7 2UH, Nottingham, UK
| | | | - Rebecca Lever
- School of Life Sciences, The University of Nottingham, NG7 2UH, Nottingham, UK
| | - Andrew Cubbon
- School of Life Sciences, The University of Nottingham, NG7 2UH, Nottingham, UK
| | - Hannah Betts
- School of Chemistry, The University of Nottingham, NG7 2RD, Nottingham, UK
| | - Vincenzo Taresco
- School of Pharmacy, The University of Nottingham, NG7 2RD, Nottingham, UK
| | - Christopher D O Cooper
- Department of Biological and Geographical Sciences, School of Applied Sciences, The University of Huddersfield, HD1 3DH, Huddersfield, UK
| | - Peter J McHugh
- MRC Weatherall Institute of Molecular Medicine (WIMM), University of Oxford, OX3 9DS, Oxford, UK
| | - Panos Soultanas
- School of Chemistry, The University of Nottingham, NG7 2RD, Nottingham, UK
| | - Edward L Bolt
- School of Life Sciences, The University of Nottingham, NG7 2UH, Nottingham, UK
| |
Collapse
|
5
|
Álvarez-Rodríguez I, Arana L, Ugarte-Uribe B, Gómez-Rubio E, Martín-Santamaría S, Garbisu C, Alkorta I. Type IV Coupling Proteins as Potential Targets to Control the Dissemination of Antibiotic Resistance. Front Mol Biosci 2020; 7:201. [PMID: 32903459 PMCID: PMC7434980 DOI: 10.3389/fmolb.2020.00201] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
The increase of infections caused by multidrug-resistant bacteria, together with the loss of effectiveness of currently available antibiotics, represents one of the most serious threats to public health worldwide. The loss of human lives and the economic costs associated to the problem of the dissemination of antibiotic resistance require immediate action. Bacteria, known by their great genetic plasticity, are capable not only of mutating their genes to adapt to disturbances and environmental changes but also of acquiring new genes that allow them to survive in hostile environments, such as in the presence of antibiotics. One of the major mechanisms responsible for the horizontal acquisition of new genes (e.g., antibiotic resistance genes) is bacterial conjugation, a process mediated by mobile genetic elements such as conjugative plasmids and integrative conjugative elements. Conjugative plasmids harboring antibiotic resistance genes can be transferred from a donor to a recipient bacterium in a process that requires physical contact. After conjugation, the recipient bacterium not only harbors the antibiotic resistance genes but it can also transfer the acquired plasmid to other bacteria, thus contributing to the spread of antibiotic resistance. Conjugative plasmids have genes that encode all the proteins necessary for the conjugation to take place, such as the type IV coupling proteins (T4CPs) present in all conjugative plasmids. Type VI coupling proteins constitute a heterogeneous family of hexameric ATPases that use energy from the ATP hydrolysis for plasmid transfer. Taking into account their essential role in bacterial conjugation, T4CPs are attractive targets for the inhibition of bacterial conjugation and, concomitantly, the limitation of antibiotic resistance dissemination. This review aims to compile present knowledge on T4CPs as a starting point for delving into their molecular structure and functioning in future studies. Likewise, the scientific literature on bacterial conjugation inhibitors has been reviewed here, in an attempt to elucidate the possibility of designing T4CP-inhibitors as a potential solution to the dissemination of multidrug-resistant bacteria.
Collapse
Affiliation(s)
- Itxaso Álvarez-Rodríguez
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain
| | - Lide Arana
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain
| | - Begoña Ugarte-Uribe
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain
| | - Elena Gómez-Rubio
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain
| | - Sonsoles Martín-Santamaría
- Department of Structural and Chemical Biology, Centro de Investigaciones Biológicas Margarita Salas, CIB-CSIC, Madrid, Spain
| | - Carlos Garbisu
- Department of Conservation of Natural Resources, Soil Microbial Ecology Group, NEIKER - Basque Institute for Agricultural Research and Development, Basque Research and Technology Alliance (BRTA), Parque Cient fico y Tecnológico de Bizkaia, Derio, Spain
| | - Itziar Alkorta
- Department of Biochemistry and Molecular Biology, University of the Basque Country, Leioa, Spain
| |
Collapse
|
6
|
Álvarez-Rodríguez I, Ugarte-Uribe B, de la Arada I, Arrondo JLR, Garbisu C, Alkorta I. Conjugative Coupling Proteins and the Role of Their Domains in Conjugation, Secondary Structure and in vivo Subcellular Location. Front Mol Biosci 2020; 7:185. [PMID: 32850972 PMCID: PMC7431656 DOI: 10.3389/fmolb.2020.00185] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/14/2020] [Indexed: 01/11/2023] Open
Abstract
Type IV Coupling Proteins (T4CPs) are essential elements in many type IV secretion systems (T4SSs). The members of this family display sequence, length, and domain architecture heterogeneity, being the conserved Nucleotide-Binding Domain the motif that defines them. In addition, most T4CPs contain a Transmembrane Domain (TMD) in the amino end and an All-Alpha Domain facing the cytoplasm. Additionally, a few T4CPs present a variable domain at the carboxyl end. The structural paradigm of this family is TrwBR388, the T4CP of conjugative plasmid R388. This protein has been widely studied, in particular the role of the TMD on the different characteristics of TrwBR388. To gain knowledge about T4CPs and their TMD, in this work a chimeric protein containing the TMD of TraJpKM101 and the cytosolic domain of TrwBR388 has been constructed. Additionally, one of the few T4CPs of mobilizable plasmids, MobBCloDF13 of mobilizable plasmid CloDF13, together with its TMD-less mutant MobBΔTMD have been studied. Mating studies showed that the chimeric protein is functional in vivo and that it exerted negative dominance against the native proteins TrwBR388 and TraJpKM101. Also, it was observed that the TMD of MobBCloDF13 is essential for the mobilization of CloDF13 plasmid. Analysis of the secondary structure components showed that the presence of a heterologous TMD alters the structure of the cytosolic domain in the chimeric protein. On the contrary, the absence of the TMD in MobBCloDF13 does not affect the secondary structure of its cytosolic domain. Subcellular localization studies showed that T4CPs have a unipolar or bipolar location, which is enhanced by the presence of the remaining proteins of the conjugative system. Unlike what has been described for TrwBR388, the TMD is not an essential element for the polar location of MobBCloDF13. The main conclusion is that the characteristics described for the paradigmatic TrwBR388 T4CP should not be ascribed to the whole T4CP family. Specifically, it has been proven that the mobilizable plasmid-related MobBCloDF13 presents different characteristics regarding the role of its TMD. This work will contribute to better understand the T4CP family, a key element in bacterial conjugation, the main mechanism responsible for antibiotic resistance spread.
Collapse
Affiliation(s)
- Itxaso Álvarez-Rodríguez
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain.,Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country (UPV/EHU), Spanish Research Council (CSIC), Leioa, Spain
| | - Begoña Ugarte-Uribe
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Igor de la Arada
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain.,Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country (UPV/EHU), Spanish Research Council (CSIC), Leioa, Spain
| | - José Luis R Arrondo
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain.,Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country (UPV/EHU), Spanish Research Council (CSIC), Leioa, Spain
| | - Carlos Garbisu
- NEIKER, Soil Microbial Ecology Group, Department of Conservation of Natural Resources, Derio, Spain
| | - Itziar Alkorta
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Leioa, Spain.,Instituto Biofisika (UPV/EHU, CSIC), University of the Basque Country (UPV/EHU), Spanish Research Council (CSIC), Leioa, Spain
| |
Collapse
|
7
|
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.
Collapse
|
8
|
Guo P, Driver D, Zhao Z, Zheng Z, Chan C, Cheng X. Controlling the Revolving and Rotating Motion Direction of Asymmetric Hexameric Nanomotor by Arginine Finger and Channel Chirality. ACS NANO 2019; 13:6207-6223. [PMID: 31067030 PMCID: PMC6595433 DOI: 10.1021/acsnano.8b08849] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nanomotors in nanotechnology are as important as engines in daily life. Many ATPases are nanoscale biomotors classified into three categories based on the motion mechanisms in transporting substrates: linear, rotating, and the recently discovered revolving motion. Most biomotors adopt a multisubunit ring-shaped structure that hydrolyzes ATP to generate force. How these biomotors control the motion direction and regulate the sequential action of their multiple subunits is intriguing. Many ATPases are hexameric with each monomer containing a conserved arginine finger. This review focuses on recent findings on how the arginine finger controls motion direction and coordinates adjacent subunit interactions in both revolving and rotating biomotors. Mechanisms of intersubunit interactions and sequential movements of individual subunits are evidenced by the asymmetrical appearance of one dimer and four monomers in high-resolution structural complexes. The arginine finger is situated at the interface of two subunits and extends into the ATP binding pocket of the downstream subunit. An arginine finger mutation results in deficiency in ATP binding/hydrolysis, substrate binding, and transport, highlighting the importance of the arginine finger in regulating energy transduction and motor function. Additionally, the roles of channel chirality and channel size are discussed as related to controlling one-way trafficking and differentiating the revolving and rotating mechanisms. Finally, the review concludes by discussing the conformational changes and entropy conversion triggered by ATP binding/hydrolysis, offering a view different from the traditional concept of ATP-mediated mechanochemical energy coupling. The elucidation of the motion mechanism and direction control in ATPases could facilitate nanomotor fabrication in nanotechnology.
Collapse
Affiliation(s)
- Peixuan Guo
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
- E-mail:
| | - Dana Driver
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Zhengyi Zhao
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Zhen Zheng
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Chun Chan
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| | - Xiaolin Cheng
- Center
for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy
and College of Medicine, Dorothy M. Davis Heart and Lung Research
Institute, Comprehensive Cancer Center and College of Pharmacy, Biophysics
Graduate Program, Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United
States
| |
Collapse
|
9
|
Amado E, Muth G, Arechaga I, Cabezón E. The FtsK-like motor TraB is a DNA-dependent ATPase that forms higher-order assemblies. J Biol Chem 2019; 294:5050-5059. [PMID: 30723158 DOI: 10.1074/jbc.ra119.007459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/01/2019] [Indexed: 11/06/2022] Open
Abstract
TraB is an FtsK-like DNA translocase responsible for conjugative plasmid transfer in mycelial Streptomyces Unlike other conjugative systems, which depend on a type IV secretion system, Streptomyces requires only TraB protein to transfer the plasmid as dsDNA. The γ-domain of this protein specifically binds to repeated 8-bp motifs on the plasmid sequence, following a mechanism that is reminiscent of the FtsK/SpoIIIE chromosome segregation system. In this work, we purified and characterized the enzymatic activity of TraB, revealing that it is a DNA-dependent ATPase that is highly stimulated by dsDNA substrates. Interestingly, we found that unlike the SpoIIIE protein, the γ-domain of TraB does not confer sequence-specific ATPase stimulation. We also found that TraB binds G-quadruplex DNA structures with higher affinity than TraB-recognition sequences (TRSs). An EM-based structural analysis revealed that TraB tends to assemble as large complexes comprising four TraB hexamers, which might be a prerequisite for DNA translocation across cell membranes. In summary, our findings shed light on the molecular mechanism used by the DNA-translocating motor TraB, which may be shared by other membrane-associated machineries involved in DNA binding and translocation.
Collapse
Affiliation(s)
- Eric Amado
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, Santander, Spain and
| | - Günther Muth
- Interfakultaeres Institut für Mikrobiologie und Infektionsmedizin Tuebingen IMIT, Mikrobiologie/Biotechnologie, Eberhard Karls Universitaet Tuebingen, 72074 Tuebingen, Germany
| | - Ignacio Arechaga
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, Santander, Spain and
| | - Elena Cabezón
- From the Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, Santander, Spain and
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
Redzej A, Ukleja M, Connery S, Trokter M, Felisberto-Rodrigues C, Cryar A, Thalassinos K, Hayward RD, Orlova EV, Waksman G. Structure of a VirD4 coupling protein bound to a VirB type IV secretion machinery. EMBO J 2017; 36:3080-3095. [PMID: 28923826 PMCID: PMC5916273 DOI: 10.15252/embj.201796629] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 08/09/2017] [Accepted: 08/22/2017] [Indexed: 01/26/2023] Open
Abstract
Type IV secretion (T4S) systems are versatile bacterial secretion systems mediating transport of protein and/or DNA. T4S systems are generally composed of 11 VirB proteins and 1 VirD protein (VirD4). The VirB1‐11 proteins assemble to form a secretion machinery and a pilus while the VirD4 protein is responsible for substrate recruitment. The structure of VirD4 in isolation is known; however, its structure bound to the VirB1‐11 apparatus has not been determined. Here, we purify a T4S system with VirD4 bound, define the biochemical requirements for complex formation and describe the protein–protein interaction network in which VirD4 is involved. We also solve the structure of this complex by negative stain electron microscopy, demonstrating that two copies of VirD4 dimers locate on both sides of the apparatus, in between the VirB4 ATPases. Given the central role of VirD4 in type IV secretion, our study provides mechanistic insights on a process that mediates the dangerous spread of antibiotic resistance genes among bacterial populations.
Collapse
Affiliation(s)
- Adam Redzej
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Marta Ukleja
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Sarah Connery
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Martina Trokter
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | | | - Adam Cryar
- Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
| | - Konstantinos Thalassinos
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK.,Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
| | - Richard D Hayward
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK.,Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
| | - Elena V Orlova
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK
| | - Gabriel Waksman
- Department of Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck, London, UK .,Division of Biosciences, Institute of Structural and Molecular Biology, University College of London, London, UK
| |
Collapse
|
12
|
Hegyi A, Szabó M, Olasz F, Kiss J. Identification of oriT and a recombination hot spot in the IncA/C plasmid backbone. Sci Rep 2017; 7:10595. [PMID: 28878309 PMCID: PMC5587640 DOI: 10.1038/s41598-017-11097-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 08/17/2017] [Indexed: 11/08/2022] Open
Abstract
Dissemination of multiresistance has been accelerating among pathogenic bacteria in recent decades. The broad host-range conjugative plasmids of the IncA/C family are effective vehicles of resistance determinants in Gram-negative bacteria. Although more than 150 family members have been sequenced to date, their conjugation system and other functions encoded by the conserved plasmid backbone have been poorly characterized. The key cis-acting locus, the origin of transfer (oriT), has not yet been unambiguously identified. We present evidence that IncA/C plasmids have a single oriT locus immediately upstream of the mobI gene encoding an indispensable transfer factor. The fully active oriT spans ca. 150-bp AT-rich region overlapping the promoters of mobI and contains multiple inverted and direct repeats. Within this region, the core domain of oriT with reduced but detectable transfer activity was confined to a 70-bp segment containing two inverted repeats and one copy of a 14-bp direct repeat. In addition to oriT, a second locus consisting of a 14-bp imperfect inverted repeat was also identified, which mimicked the function of oriT but which was found to be a recombination site. Recombination between two identical copies of these sites is RecA-independent, requires a plasmid-encoded recombinase and resembles the functioning of dimer-resolution systems.
Collapse
Affiliation(s)
- Anna Hegyi
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, 4. Szent-Györgyi Albert str., Gödöllő, Hungary
| | - Mónika Szabó
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, 4. Szent-Györgyi Albert str., Gödöllő, Hungary
| | - Ferenc Olasz
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, 4. Szent-Györgyi Albert str., Gödöllő, Hungary
| | - János Kiss
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, 4. Szent-Györgyi Albert str., Gödöllő, Hungary.
| |
Collapse
|
13
|
Substrate translocation involves specific lysine residues of the central channel of the conjugative coupling protein TrwB. Mol Genet Genomics 2017; 292:1037-1049. [PMID: 28597316 DOI: 10.1007/s00438-017-1331-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Conjugative transfer of plasmid R388 requires the coupling protein TrwB for protein and DNA transport, but their molecular role in transport has not been deciphered. We investigated the role of residues protruding into the central channel of the TrwB hexamer by a mutational analysis. Mutations affecting lysine residues K275, K398, and K421, and residue S441, all facing the internal channel, affected transport of both DNA and the relaxase protein in vivo. The ATPase activity of the purified soluble variants was affected significantly in the presence of accessory protein TrwA or DNA, correlating with their behaviour in vivo. Alteration of residues located at the cytoplasmic or the inner membrane interface resulted in lower activity in vivo and in vitro, while variants affecting residues in the central region of the channel showed increased DNA and protein transfer efficiency and higher ATPase activity, especially in the absence of TrwA. In fact, these variants could catalyze DNA transfer in the absence of TrwA under conditions in which the wild-type system was transfer deficient. Our results suggest that protein and DNA molecules have the same molecular requirements for translocation by Type IV secretion systems, with residues at both ends of the TrwB channel controlling the opening-closing mechanism, while residues embedded in the channel would set the pace for substrate translocation (both protein and DNA) in concert with TrwA.
Collapse
|
14
|
Mitochondrial DNA in innate immune responses and inflammatory pathology. Nat Rev Immunol 2017; 17:363-375. [PMID: 28393922 DOI: 10.1038/nri.2017.21] [Citation(s) in RCA: 607] [Impact Index Per Article: 86.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mitochondrial DNA (mtDNA) - which is well known for its role in oxidative phosphorylation and maternally inherited mitochondrial diseases - is increasingly recognized as an agonist of the innate immune system that influences antimicrobial responses and inflammatory pathology. On entering the cytoplasm, extracellular space or circulation, mtDNA can engage multiple pattern-recognition receptors in cell-type- and context-dependent manners to trigger pro-inflammatory and type I interferon responses. Here, we review the expanding research field of mtDNA in innate immune responses to highlight new mechanistic insights and discuss the physiological and pathological relevance of this exciting area of mitochondrial biology.
Collapse
|
15
|
Abstract
Type IV coupling proteins (T4CPs) are essential constituents of most type IV secretion systems (T4SSs), and probably the most intriguing component in terms of their evolutionary origin and functional role. Coupling proteins have coevolved with their cognate secretion system and translocated substrates. They are present in all conjugative systems, leading to the suggestion that they play a specific role in DNA transfer. However, they are also part of many T4SSs involved in bacterial virulence, where they are required for protein translocation, with no apparent involvement in DNA secretion. Their name reflects genetic and biochemical evidence of a connecting role between the substrate and the T4SS, thus probably playing a major role in substrate recruitment. Increasing evidence supports also a role in signal transmission leading to activation of secretion. Most studies have addressed conjugative coupling proteins of the VirD4-like protein family. Their conserved features include a nucleotide-binding domain, essential for substrate translocation, a C-terminal domain involved in substrate interactions, and a transmembrane domain anchoring them to the inner membrane, which is an important regulator of protein function. Purified soluble deletion mutants display ATP hydrolysis activity and unspecific DNA binding. Elucidation of the 3D structure of the soluble deletion mutant of the conjugative coupling protein TrwB, TrwBΔN70, provided the basis for further mutagenesis studies rendering interesting insights into the structure-function of these proteins. Their key role as couplers between substrate and transporter provides biotechnological potential as targets for anti-virulence strategies, as well as for customization of substrate delivery through heterologous secretion systems.
Collapse
Affiliation(s)
- Matxalen Llosa
- Departamento de Biología Molecular, Universidad de Cantabria (UC), and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), UC-CSIC-SODERCAN, C/Albert Einstein 22, 39011, Santander, Spain.
| | - Itziar Alkorta
- Departamento de Bioquímica y Biología Molecular (UPV/EHU), Instituto Biofisika (UPV/EHU, CSIC), Barrio Sarriena S/N, 48940, Leioa, Spain
| |
Collapse
|
16
|
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.
Collapse
Affiliation(s)
- Vidya Chandran Darbari
- Section of Structural Biology, Department of Medicine, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | | |
Collapse
|
17
|
The All-Alpha Domains of Coupling Proteins from the Agrobacterium tumefaciens VirB/VirD4 and Enterococcus faecalis pCF10-Encoded Type IV Secretion Systems Confer Specificity to Binding of Cognate DNA Substrates. J Bacteriol 2015; 197:2335-49. [PMID: 25939830 DOI: 10.1128/jb.00189-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/23/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Bacterial type IV coupling proteins (T4CPs) bind and mediate the delivery of DNA substrates through associated type IV secretion systems (T4SSs). T4CPs consist of a transmembrane domain, a conserved nucleotide-binding domain (NBD), and a sequence-variable helical bundle called the all-alpha domain (AAD). In the T4CP structural prototype, plasmid R388-encoded TrwB, the NBD assembles as a homohexamer resembling RecA and DNA ring helicases, and the AAD, which sits at the channel entrance of the homohexamer, is structurally similar to N-terminal domain 1 of recombinase XerD. Here, we defined the contributions of AADs from the Agrobacterium tumefaciens VirD4 and Enterococcus faecalis PcfC T4CPs to DNA substrate binding. AAD deletions abolished DNA transfer, whereas production of the AAD in otherwise wild-type donor strains diminished the transfer of cognate but not heterologous substrates. Reciprocal swaps of AADs between PcfC and VirD4 abolished the transfer of cognate DNA substrates, although strikingly, the VirD4-AADPcfC chimera (VirD4 with the PcfC AAD) supported the transfer of a mobilizable plasmid. Purified AADs from both T4CPs bound DNA substrates without sequence preference but specifically bound cognate processing proteins required for cleavage at origin-of-transfer sequences. The soluble domains of VirD4 and PcfC lacking their AADs neither exerted negative dominance in vivo nor specifically bound cognate processing proteins in vitro. Our findings support a model in which the T4CP AADs contribute to DNA substrate selection through binding of associated processing proteins. Furthermore, MOBQ plasmids have evolved a docking mechanism that bypasses the AAD substrate discrimination checkpoint, which might account for their capacity to promiscuously transfer through many different T4SSs. IMPORTANCE For conjugative transfer of mobile DNA elements, members of the VirD4/TraG/TrwB receptor superfamily bind cognate DNA substrates through mechanisms that are largely undefined. Here, we supply genetic and biochemical evidence that a helical bundle, designated the all-alpha domain (AAD), of T4SS receptors functions as a substrate specificity determinant. We show that AADs from two substrate receptors, Agrobacterium tumefaciens VirD4 and Enterococcus faecalis PcfC, bind DNA without sequence or strand preference but specifically bind the cognate relaxases responsible for nicking and piloting the transferred strand through the T4SS. We propose that interactions of receptor AADs with DNA-processing factors constitute a basis for selective coupling of mobile DNA elements with type IV secretion channels.
Collapse
|
18
|
Common mechanisms of DNA translocation motors in bacteria and viruses using one-way revolution mechanism without rotation. Biotechnol Adv 2015; 32:853-72. [PMID: 24913057 DOI: 10.1016/j.biotechadv.2014.01.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 01/24/2014] [Accepted: 01/25/2014] [Indexed: 12/15/2022]
Abstract
Biomotors were once described into two categories: linear motor and rotation motor. Recently, a third type of biomotor with revolution mechanism without rotation has been discovered. By analogy, rotation resembles the Earth rotating on its axis in a complete cycle every 24h, while revolution resembles the Earth revolving around the Sun one circle per 365 days (see animations http://nanobio.uky.edu/movie.html). The action of revolution that enables a motor free of coiling and torque has solved many puzzles and debates that have occurred throughout the history of viral DNA packaging motor studies. It also settles the discrepancies concerning the structure, stoichiometry, and functioning of DNA translocation motors. This review uses bacteriophages Phi29, HK97, SPP1, P22, T4, and T7 as well as bacterial DNA translocase FtsK and SpoIIIE or the large eukaryotic dsDNA viruses such as mimivirus and vaccinia virus as examples to elucidate the puzzles. These motors use ATPase, some of which have been confirmed to be a hexamer, to revolve around the dsDNA sequentially. ATP binding induces conformational change and possibly an entropy alteration in ATPase to a high affinity toward dsDNA; but ATP hydrolysis triggers another entropic and conformational change in ATPase to a low affinity for DNA, by which dsDNA is pushed toward an adjacent ATPase subunit. The rotation and revolution mechanisms can be distinguished by the size of channel: the channels of rotation motors are equal to or smaller than 2 nm, that is the size of dsDNA, whereas channels of revolution motors are larger than 3 nm. Rotation motors use parallel threads to operate with a right-handed channel, while revolution motors use a left-handed channel to drive the right-handed DNA in an anti-chiral arrangement. Coordination of several vector factors in the same direction makes viral DNA-packaging motors unusually powerful and effective. Revolution mechanism that avoids DNA coiling in translocating the lengthy genomic dsDNA helix could be advantageous for cell replication such as bacterial binary fission and cell mitosis without the need for topoisomerase or helicase to consume additional energy.
Collapse
|
19
|
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: 120] [Impact Index Per Article: 12.0] [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.
Collapse
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
| |
Collapse
|
20
|
Lorenzo-Díaz F, Fernández-López C, Garcillán-Barcia MP, Espinosa M. Bringing them together: plasmid pMV158 rolling circle replication and conjugation under an evolutionary perspective. Plasmid 2014; 74:15-31. [PMID: 24942190 PMCID: PMC7103276 DOI: 10.1016/j.plasmid.2014.05.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 11/29/2022]
Abstract
The replication and transfer of rolling circle-replicating plasmids is reviewed. Comparisons of replication and transfer cassettes are presented. The current understanding of the pMV158 DNA transfer mechanism is reviewed.
Rolling circle-replicating plasmids constitute a vast family that is particularly abundant in, but not exclusive of, Gram-positive bacteria. These plasmids are constructed as cassettes that harbor genes involved in replication and its control, mobilization, resistance determinants and one or two origins of lagging strand synthesis. Any given plasmid may contain all, some, or just only the replication cassette. We discuss here the family of the promiscuous streptococcal plasmid pMV158, with emphasis on its mobilization functions: the product of the mobM gene, prototype of the MOBV relaxase family, and its cognate origin of transfer, oriT. Amongst the subfamily of MOBV1 plasmids, three groups of oriT sequences, represented by plasmids pMV158, pT181, and p1414 were identified. In the same subfamily, we found four types of single-strand origins, namely ssoA, ssoU, ssoW, and ssoT. We found that plasmids of the rolling-circle Rep_2 family (to which pMV158 belongs) are more frequently found in Lactobacillales than in any other bacterial order, whereas Rep_1 initiators seemed to prefer hosts included in the Bacillales order. In parallel, MOBV1 relaxases associated with Rep_2 initiators tended to cluster separately from those linked to Rep_1 plasmids. The updated inventory of MOBV1 plasmids still contains exclusively mobilizable elements, since no genes associated with conjugative transfer (other than the relaxase) were detected. These plasmids proved to have a great plasticity at using a wide variety of conjugative apparatuses. The promiscuous recognition of non-cognate oriT sequences and the role of replication origins for lagging-strand origin in the host range of these plasmids are also discussed.
Collapse
Affiliation(s)
- Fabián Lorenzo-Díaz
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria and Instituto Universitario de Enfermedades Tropicales y Salud Pública de Canarias, Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Santa Cruz de Tenerife, Spain.
| | - Cris Fernández-López
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, E-28040 Madrid, Spain.
| | - M Pilar Garcillán-Barcia
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria - CSIC-SODERCAN, Santander, Cantabria, Spain.
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu, 9, E-28040 Madrid, Spain.
| |
Collapse
|
21
|
Segura RL, Aguila-Arcos S, Ugarte-Uribe B, Vecino AJ, de la Cruz F, Goñi FM, Alkorta I. Subcellular location of the coupling protein TrwB and the role of its transmembrane domain. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:223-30. [PMID: 24016550 DOI: 10.1016/j.bbamem.2013.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 12/01/2022]
Abstract
Conjugation is the most important mechanism for horizontal gene transfer and it is the main responsible for the successful adaptation of bacteria to the environment. Conjugative plasmids are the DNA molecules transferred and a multiprotein system encoded by the conjugative plasmid itself is necessary. The high number of proteins involved in the process suggests that they should have a defined location in the cell and therefore, they should be recruited to that specific point. One of these proteins is the coupling protein that plays an essential role in bacterial conjugation. TrwB is the coupling protein of R388 plasmid that is divided in two domains: i) The N-terminal domain referred as transmembrane domain and ii) a large cytosolic domain that contains a nucleotide-binding motif similar to other ATPases. To investigate the role of these domains in the subcellular location of TrwB, we constructed two mutant proteins that comprised the transmembrane (TrwBTM) or the cytoplasmic (TrwBΔN70) domain of TrwB. By immunofluorescence and GFP-fusion proteins we demonstrate that TrwB and TrwBTM mutant protein were localized to the cell pole independently of the remaining R388 proteins. On the contrary, a soluble mutant protein (TrwBΔN70) was localized to the cytoplasm in the absence of R388 proteins. However, in the presence of other R388-encoded proteins, TrwBΔN70 localizes uniformly to the cell membrane, suggesting that interactions between the cytosolic domain of TrwB and other membrane proteins of R388 plasmid may happen. Our results suggest that the transmembrane domain of TrwB leads the protein to the cell pole.
Collapse
Affiliation(s)
- Rosa L Segura
- Unidad de Biofísica (CSIC, UPV/EHU), and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, Apdo. 644, 48080 Bilbao, Spain
| | | | | | | | | | | | | |
Collapse
|
22
|
Segura RL, Águila-Arcos S, Ugarte-Uribe B, Vecino AJ, de la Cruz F, Goñi FM, Alkorta I. The transmembrane domain of the T4SS coupling protein TrwB and its role in protein–protein interactions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2015-25. [DOI: 10.1016/j.bbamem.2013.05.022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/14/2013] [Accepted: 05/22/2013] [Indexed: 11/15/2022]
|
23
|
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.
Collapse
|
24
|
Bañuelos S, Lectez B, Taneva SG, Ormaza G, Alonso-Mariño M, Calle X, Urbaneja MA. Recognition of intermolecular G-quadruplexes by full length nucleophosmin. Effect of a leukaemia-associated mutation. FEBS Lett 2013; 587:2254-9. [PMID: 23742937 DOI: 10.1016/j.febslet.2013.05.055] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 05/08/2013] [Accepted: 05/21/2013] [Indexed: 11/19/2022]
Abstract
Nucleophosmin (NPM) is a nucleolar protein involved in ribosome biogenesis. NPM1 gene is frequently mutated in acute myeloid leukaemia (AML), correlating with aberrant cytoplasmic localization of the protein. NPM attachment to the nucleolus in physiological conditions probably depends on binding to nucleic acids, and this recognition could be altered in AML. NPM associates to guanine-rich DNA sequences, able to fold as "G-quadruplexes". We have analyzed the interaction of pentameric, full length NPM with G-rich oligonucleotides, finding that the protein binds preferentially high-order G-quadruplexes. AML-associated mutation significantly hampers DNA binding, pointing to a possible mechanism contributing to pathological mislocalization of NPM.
Collapse
Affiliation(s)
- Sonia Bañuelos
- Biophysics Unit (CSIC/UPV-EHU), Department of Biochemistry and Molecular Biology, University of Basque Country (UPV-EHU), POB 644, 48080 Bilbao, Spain.
| | | | | | | | | | | | | |
Collapse
|
25
|
Transcription of a cis-acting, noncoding, small RNA is required for pilin antigenic variation in Neisseria gonorrhoeae. PLoS Pathog 2013; 9:e1003074. [PMID: 23349628 PMCID: PMC3547852 DOI: 10.1371/journal.ppat.1003074] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 10/19/2012] [Indexed: 11/25/2022] Open
Abstract
The strict human pathogen Neisseria gonorrhoeae can utilize homologous recombination to generate antigenic variability in targets of immune surveillance. To evade the host immune response, N. gonorrhoeae promotes high frequency gene conversion events between many silent pilin copies and the expressed pilin locus (pilE), resulting in the production of variant pilin proteins. Previously, we identified a guanine quartet (G4) structure localized near pilE that is required for the homologous recombination reactions leading to pilin antigenic variation (Av). In this work, we demonstrate that inactivating the promoter of a small non-coding RNA (sRNA) that initiates within the G4 forming sequence blocks pilin Av. The sRNA promoter is conserved in all sequenced gonococcal strains, and mutations in the predicted transcript downstream of the G4 forming sequence do not alter pilin Av. A mutation that produces a stronger promoter or substitution of the pilE G4-associated sRNA promoter with a phage promoter (when the phage polymerase was expressed) produced wild-type levels of pilin Av. Altering the direction and orientation of the pilE G4-associated sRNA disrupted pilin Av. In addition, expression of the sRNA at a distal site on the gonococcal chromosome in the context of a promoter mutant did not support pilin Av. We conclude that the DNA containing the G-rich sequence can only form the G4 structure during transcription of this sRNA, thus providing a unique molecular step for the initiation of programmed recombination events. To evade the host immune response, pathogens have evolved mechanisms to provide genetic diversity in targets of immune surveillance. Organisms that express these diversification systems are under strong evolutionary pressure to provide subpopulations of preexisting variants and often rely on cellular recombination machinery to catalyze dedicated high-frequency reactions without disturbing genome integrity. Previously, we defined a guanine quartet (G4) structure in the strict human pathogen Neisseria gonorrhoeae that is required for initiating the homologous recombination reactions leading to pilin antigenic variation (Av). G4 structures have been implicated in many biological processes, however the mechanisms allowing their formation within a chromosome have not been elucidated. In this work, we show a direct link between transcription of a small RNA (sRNA) that initiates within the G4 structure forming sequence and pilin Av and conclude that the process of transcription is necessary for G4 structure formation. sRNAs have emerged as important regulatory molecules in both eukaryotes and prokaryotes, and this is a novel activity of a sRNA in a bacterium. We anticipate that the reliance of G4 structure formation on transcription is a mechanism used by other biological systems that rely on this alternative DNA structure.
Collapse
|
26
|
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.
Collapse
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
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Cabezon E, Lanza VF, Arechaga I. Membrane-associated nanomotors for macromolecular transport. Curr Opin Biotechnol 2011; 23:537-44. [PMID: 22189002 DOI: 10.1016/j.copbio.2011.11.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 11/18/2011] [Accepted: 11/25/2011] [Indexed: 11/19/2022]
Abstract
Nature has endowed cells with powerful nanomotors to accomplish intricate mechanical tasks, such as the macromolecular transport across membranes occurring in cell division, bacterial conjugation, and in a wide variety of secretion systems. These biological motors couple the chemical energy provided by ATP hydrolysis to the mechanical work needed to transport DNA and/or protein effectors. Here, we review what is known about the molecular mechanisms of these membrane-associated machines. Sequence and structural comparison between these ATPases reveal that they share a similar motor domain, suggesting a common evolutionary ancestor. Learning how these machines operate will lead the design of nanotechnology devices with unique applications in medicine and engineering.
Collapse
Affiliation(s)
- Elena Cabezon
- Departamento de Biología Molecular, Universidad de Cantabria, and Instituto de Biomedicina y Biotecnología de Cantabria, UC-SODERCAN-CSIC, C. Herrera Oria s/n, 39011 Santander, Spain.
| | | | | |
Collapse
|
28
|
|
29
|
Abstract
Hel308 is a superfamily 2 helicase/translocase that is conserved throughout archaea and in some eukaryotes for repair of genotoxic lesions such as ICLs (interstrand DNA cross-links). Atomic structures of archaeal Hel308 have allowed mechanistic insights into ATPase and helicase functions, but have also highlighted structures that currently lack a known function, such as an unexpected WH (winged helix) domain. This domain and similar overall protein structural organization was also identified in other superfamily 2 helicases that process RNA molecules in eukaryotes: Brr2, Mtr4 and Prp43p. We survey the structure of Hel308 with regard to its WH domain in particular and its function(s) in maintaining structural integrity of the overall Hel308 ring structure, and possibly during interactions of Hel308 with other proteins and/or forked DNA.
Collapse
|
30
|
Peña A, Ripoll-Rozada J, Zunzunegui S, Cabezón E, de la Cruz F, Arechaga I. Autoinhibitory regulation of TrwK, an essential VirB4 ATPase in type IV secretion systems. J Biol Chem 2011; 286:17376-82. [PMID: 21454654 DOI: 10.1074/jbc.m110.208942] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Type IV secretion systems (T4SS) mediate the transfer of DNA and protein substrates to target cells. TrwK, encoded by the conjugative plasmid R388, is a member of the VirB4 family, comprising the largest and most conserved proteins of T4SS. In a previous work we demonstrated that TrwK is able to hydrolyze ATP. Here, based on the structural homology of VirB4 proteins with the DNA-pumping ATPase TrwB coupling protein, we generated a series of variants of TrwK where fragments of the C-terminal domain were sequentially truncated. Surprisingly, the in vitro ATPase activity of these TrwK variants was much higher than that of the wild-type enzyme. Moreover, addition of a synthetic peptide containing the amino acid residues comprising this C-terminal region resulted in the specific inhibition of the TrwK variants lacking such domain. These results indicate that the C-terminal end of TrwK plays an important regulatory role in the functioning of the T4SS.
Collapse
Affiliation(s)
- Alejandro Peña
- Departamento de Biología Molecular, Universidad de Cantabria and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), UC-IDICAN-CSIC, Santander 39011, Spain
| | | | | | | | | | | |
Collapse
|