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Srivastava V, Bandhu S, Mishra S, Chaudhuri TK. Calcium-induced structural transitions are central to the folding, function, and processing of serratiopeptidase zymogen into mature form. FEBS J 2024; 291:1958-1973. [PMID: 38700222 DOI: 10.1111/febs.17090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/05/2024] [Accepted: 02/01/2024] [Indexed: 05/05/2024]
Abstract
Serratia marcescens is an emerging health-threatening, gram-negative opportunistic pathogen associated with a wide variety of localized and life-threatening systemic infections. One of the most crucial virulence factors produced by S. marcescens is serratiopeptidase, a 50.2-kDa repeats-in-toxin (RTX) family broad-specificity zinc metalloprotease. RTX family proteins are functionally diverse exoproteins of gram-negative bacteria that exhibit calcium-dependent structural dynamicity and are secreted through a common type-1 secretion system (T1SS) machinery. To evaluate the impact of various divalent ligands on the folding and maturation of serratiopeptidase zymogen, the protein was purified and a series of structural and functional investigations were undertaken. The results indicate that calcium binding to the C-terminal RTX domain acts as a folding switch, triggering a disordered-to-ordered transition in the enzyme's conformation. Further, the auto-processing of the 16-amino acid N-terminal pro-peptide results in the maturation of the enzyme. The binding of calcium ions to serratiopeptidase causes a highly cooperative conformational transition in its structure, which is essential for the enzyme's activation and maturation. This conformational change is accompanied by an increase in solubility and enzymatic activity. For efficient secretion and to minimize intracellular toxicity, the enzyme needs to be in an unfolded extended form. The calcium-rich extracellular environment favors the folding and processing of zymogen into mature serratiopeptidase, i.e., the holo-form required by S. marcescens to establish infections and survive in different environmental niches.
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Affiliation(s)
- Vishal Srivastava
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, India
| | - Sheetal Bandhu
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, India
| | - Shivam Mishra
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, India
| | - Tapan K Chaudhuri
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, India
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2
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Abettan A, Nguyen MH, Ladant D, Monticelli L, Chenal A. CyaA translocation across eukaryotic cell membranes. Front Mol Biosci 2024; 11:1359408. [PMID: 38584704 PMCID: PMC10995232 DOI: 10.3389/fmolb.2024.1359408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/23/2024] [Indexed: 04/09/2024] Open
Affiliation(s)
- Amiel Abettan
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Molecular Microbiology and Structural Biochemistry Laboratory, CNRS UMR 5086, University of Lyon, IBCP, Lyon, France
| | - Minh-Ha Nguyen
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Université de Paris Cité, Paris, France
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biological NMR and HDX-MS Technological Platform, Paris, France
| | - Daniel Ladant
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Université de Paris Cité, Paris, France
| | - Luca Monticelli
- Molecular Microbiology and Structural Biochemistry Laboratory, CNRS UMR 5086, University of Lyon, IBCP, Lyon, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), Lyon, France
| | - Alexandre Chenal
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Université de Paris Cité, Paris, France
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3
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Abdian PL, Malori MS, Caramelo JJ, Checchi AM, Russo DM, Zorreguieta A, Berretta MF, Benintende G. Fusion of a bacterial cadherin-like domain and green fluorescent protein as a specific probe to study biofilm matrix formation in Rhizobium spp. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 36748557 DOI: 10.1099/mic.0.001284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Rhizobium adhering proteins or 'Raps' are secreted proteins identified in a very restricted group of rhizobial strains, specifically those belonging to R. leguminosarum and R. etli. The distinctive feature of members of the Rap family is the presence of one or two cadherin-like domains or CHDLs that are also present in numerous extracellular bacterial and archaeal proteins and were proposed to confer carbohydrate binding ability. We have previously made an in-depth characterization of RapA2, a calcium-binding lectin, composed by two CHDLs, involved in biofilm matrix remodelling in R. leguminosarum bv. viciae 3841. In this study, CHDLs derived from RapA2 were analysed in detail, finding significant structural and functional differences despite their considerable sequence similarity. Only the carboxy-terminal CHDL retained properties similar to those displayed by RapA2. Our findings were used to obtain a novel fluorescent probe to study biofilm matrix development by confocal laser scanning microscopy, and also to shed some light on the role of the ubiquitous CHDL domains in bacterial secreted proteins.
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Affiliation(s)
- Patricia L Abdian
- Instituto de Microbiología y Zoología Agrícola (IMyZA), G.V. al IABiMo, INTA-CONICET, Nicolás Repetto y de los Reseros s/n, 1686, Hurlingham, Buenos Aires, Argentina
| | - María Soledad Malori
- Fundación Instituto Leloir, IIBBA CONICET, Patricias Argentinas 435, 1405, Buenos Aires, Argentina
| | - Julio J Caramelo
- Fundación Instituto Leloir, IIBBA CONICET, Patricias Argentinas 435, 1405, Buenos Aires, Argentina
| | - Abi Maglio Checchi
- Instituto de Microbiología y Zoología Agrícola (IMyZA), G.V. al IABiMo, INTA-CONICET, Nicolás Repetto y de los Reseros s/n, 1686, Hurlingham, Buenos Aires, Argentina
| | - Daniela M Russo
- Fundación Instituto Leloir, IIBBA CONICET, Patricias Argentinas 435, 1405, Buenos Aires, Argentina
| | - Angeles Zorreguieta
- Fundación Instituto Leloir, IIBBA CONICET, Patricias Argentinas 435, 1405, Buenos Aires, Argentina
| | - Marcelo F Berretta
- Instituto de Microbiología y Zoología Agrícola (IMyZA), G.V. al IABiMo, INTA-CONICET, Nicolás Repetto y de los Reseros s/n, 1686, Hurlingham, Buenos Aires, Argentina
| | - Graciela Benintende
- Instituto de Microbiología y Zoología Agrícola (IMyZA), G.V. al IABiMo, INTA-CONICET, Nicolás Repetto y de los Reseros s/n, 1686, Hurlingham, Buenos Aires, Argentina
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4
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Bystranowska D, Skorupska A, Sołtys K, Padjasek M, Krężel A, Żak A, Kaus-Drobek M, Taube M, Kozak M, Ożyhar A. Nucleobindin-2 consists of two structural components: The Zn 2+-sensitive N-terminal half, consisting of nesfatin-1 and -2, and the Ca 2+-sensitive C-terminal half, consisting of nesfatin-3. Comput Struct Biotechnol J 2021; 19:4300-4318. [PMID: 34429849 PMCID: PMC8361300 DOI: 10.1016/j.csbj.2021.07.036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 12/01/2022] Open
Abstract
Nucleobindin-2 (Nucb2) is a protein that has been suggested to play roles in a variety of biological processes. Nucb2 contains two Ca2+/Mg2+-binding EF-hand domains separated by an acidic amino acid residue-rich region and a leucine zipper. All of these domains are located within the C-terminal half of the protein. At the N-terminal half, Nucb2 also possesses a putative Zn2+-binding motif. In our recent studies, we observed that Nucb2 underwent Ca2+-dependent compaction and formed a mosaic-like structure consisting of intertwined disordered and ordered regions at its C-terminal half. The aim of this study was to investigate the impact of two other potential ligands: Mg2+, which possesses chemical properties similar to those of Ca2+, and Zn2+, for which a putative binding motif was identified. In this study, we demonstrated that the binding of Mg2+ led to oligomerization state changes with no significant secondary or tertiary structural alterations of Nucb2. In contrast, Zn2+ binding had a more pronounced effect on the structure of Nucb2, leading to the local destabilization of its N-terminal half while also inducing changes within its C-terminal half. These structural rearrangements resulted in the oligomerization and/or aggregation of Nucb2 molecules. Taken together, the results of our previous and current research help to elucidate the structure of the Nucb2, which can be divided into two parts: the Zn2+-sensitive N-terminal half (consisting of nesfatin-1 and -2) and the Ca2+-sensitive C-terminal half (consisting of nesfatin-3). These results may also help to open a new discussion regarding the diverse roles that metal cations play in regulating the structure of Nucb2 and the various physiological functions of this protein.
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Affiliation(s)
- Dominika Bystranowska
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Anna Skorupska
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Katarzyna Sołtys
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Michał Padjasek
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Artur Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Andrzej Żak
- Faculty of Mechanical Engineering, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Magdalena Kaus-Drobek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Michał Taube
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
| | - Maciej Kozak
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Czerwone Maki 98, 30-392 Kraków, Poland
| | - Andrzej Ożyhar
- Department of Biochemistry, Molecular Biology and Biotechnology, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
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5
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Voegele A, Sadi M, O'Brien DP, Gehan P, Raoux‐Barbot D, Davi M, Hoos S, Brûlé S, Raynal B, Weber P, Mechaly A, Haouz A, Rodriguez N, Vachette P, Durand D, Brier S, Ladant D, Chenal A. A High-Affinity Calmodulin-Binding Site in the CyaA Toxin Translocation Domain is Essential for Invasion of Eukaryotic Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2003630. [PMID: 33977052 PMCID: PMC8097335 DOI: 10.1002/advs.202003630] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/10/2020] [Indexed: 06/12/2023]
Abstract
The molecular mechanisms and forces involved in the translocation of bacterial toxins into host cells are still a matter of intense research. The adenylate cyclase (CyaA) toxin from Bordetella pertussis displays a unique intoxication pathway in which its catalytic domain is directly translocated across target cell membranes. The CyaA translocation region contains a segment, P454 (residues 454-484), which exhibits membrane-active properties related to antimicrobial peptides. Herein, the results show that this peptide is able to translocate across membranes and to interact with calmodulin (CaM). Structural and biophysical analyses reveal the key residues of P454 involved in membrane destabilization and calmodulin binding. Mutational analysis demonstrates that these residues play a crucial role in CyaA translocation into target cells. In addition, calmidazolium, a calmodulin inhibitor, efficiently blocks CyaA internalization. It is proposed that after CyaA binding to target cells, the P454 segment destabilizes the plasma membrane, translocates across the lipid bilayer and binds calmodulin. Trapping of CyaA by the CaM:P454 interaction in the cytosol may assist the entry of the N-terminal catalytic domain by converting the stochastic motion of the polypeptide chain through the membrane into an efficient vectorial chain translocation into host cells.
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Affiliation(s)
- Alexis Voegele
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
- Université de ParisSorbonne Paris CitéParis75006France
| | - Mirko Sadi
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
- Université de ParisSorbonne Paris CitéParis75006France
| | - Darragh Patrick O'Brien
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Pauline Gehan
- Sorbonne UniversitéÉcole normale supérieurePSL UniversityCNRSLaboratoire des biomoléculesLBMParis75005France
| | - Dorothée Raoux‐Barbot
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Maryline Davi
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Sylviane Hoos
- Plateforme de Biophysique MoléculaireInstitut PasteurUMR 3528 CNRSParis75015France
| | - Sébastien Brûlé
- Plateforme de Biophysique MoléculaireInstitut PasteurUMR 3528 CNRSParis75015France
| | - Bertrand Raynal
- Plateforme de Biophysique MoléculaireInstitut PasteurUMR 3528 CNRSParis75015France
| | - Patrick Weber
- Institut PasteurPlate‐forme de cristallographie‐C2RTUMR‐3528 CNRSParis75015France
| | - Ariel Mechaly
- Institut PasteurPlate‐forme de cristallographie‐C2RTUMR‐3528 CNRSParis75015France
| | - Ahmed Haouz
- Institut PasteurPlate‐forme de cristallographie‐C2RTUMR‐3528 CNRSParis75015France
| | - Nicolas Rodriguez
- Sorbonne UniversitéÉcole normale supérieurePSL UniversityCNRSLaboratoire des biomoléculesLBMParis75005France
| | - Patrice Vachette
- Université Paris‐SaclayCEACNRSInstitute for Integrative Biology of the Cell (I2BC)Gif‐sur‐Yvette91198France
| | - Dominique Durand
- Université Paris‐SaclayCEACNRSInstitute for Integrative Biology of the Cell (I2BC)Gif‐sur‐Yvette91198France
| | - Sébastien Brier
- Biological NMR Technological PlateformCenter for Technological Resources and ResearchDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Daniel Ladant
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Alexandre Chenal
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
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Ali NSM, Salleh AB, Leow TC, Rahman RNZRA, Ali MSM. The Influence of Calcium toward Order/Disorder Conformation of Repeat-in-Toxin (RTX) Structure of Family I.3 Lipase from Pseudomonas fluorescens AMS8. Toxins (Basel) 2020; 12:toxins12090579. [PMID: 32916891 PMCID: PMC7551394 DOI: 10.3390/toxins12090579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 11/16/2022] Open
Abstract
Calcium-binding plays a decisive role in the folding and stabilization of many RTX proteins, especially for the RTX domain. Although many studies have been conducted to prove the contribution of Ca2+ ion toward the folding and stabilization of RTX proteins, its functional dynamics and conformational structural changes remain elusive. Here, molecular docking and molecular dynamics (MD) simulations were performed to analyze the contribution of Ca2+ ion toward the folding and stabilization of the RTX lipase (AMS8 lipase) structure. AMS8 lipase contains six Ca2+ ions (Ca1–Ca6). Three Ca2+ ions (Ca3, Ca4, and Ca5) were bound to the RTX parallel β-roll motif repeat structure (RTX domain). The metal ion (Ca2+) docking analysis gives a high binding energy, especially for Ca4 and Ca5 which are tightly bound to the RTX domain. The function of each Ca2+ ion is further analyzed using the MD simulation. The removal of Ca3, Ca4, and Ca5 caused the AMS8 lipase structure to become unstable and unfolded. The results suggested that Ca3, Ca4, and Ca5 stabilized the RTX domain. In conclusion, Ca3, Ca4, and Ca5 play a crucial role in the folding and stabilization of the RTX domain, which sustain the integrity of the overall AMS8 lipase structure.
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Affiliation(s)
- Nur Shidaa Mohd Ali
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Abu Bakar Salleh
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
| | - Thean Chor Leow
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Raja Noor Zaliha Raja Abd Rahman
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Mohd Shukuri Mohamad Ali
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
- Correspondence:
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7
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Calcium ions modulate the structure of the intrinsically disordered Nucleobindin-2 protein. Int J Biol Macromol 2020; 154:1091-1104. [PMID: 32184136 DOI: 10.1016/j.ijbiomac.2020.03.110] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 01/05/2023]
Abstract
Nucleobindin-2 (Nucb2) is a widely expressed multi-domain protein. Nucb2 participates in many physiological processes, i.e. calcium level maintenance, feeding regulation in the hypothalamus, emotion and stress regulation, and many others. To date, this protein has not been structurally characterized. We describe the first comparative structural analysis of two homologs, a Gallus gallus and a Homo sapiens Nucb2. The in silico analysis suggested that apo-Nucb2s contain a mosaic-like structure, consisting of intertwined disordered and ordered regions. Surprisingly, the hydrogen-deuterium exchange mass spectrometry results revealed that Nucb2 is divided into two parts: an N-terminal half with a stable mosaic-like structure and a disordered C-terminal half. However, the presence of Ca2+ induces the formation of a mosaic-like structure in the C-terminal half of the Nucb2s. The Ca2+ also affects the tertiary and quaternary structure of Nucb2s. The presence of Ca2+ leads to an overall compaction of the Nucb2 molecule, resulting in structural change that is propagated along the molecule, which in turn affects the quaternary structure of the protein. Intrinsic disorder, and the mosaic-like Ca2+ dependent structure of Nucb2s, might be seen as the molecular factors responsible for their multifunctionality. Thus, Nucb2s might function as the versatile Ca2+ sensor involved in signal transduction.
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8
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Baumann U. Structure-Function Relationships of the Repeat Domains of RTX Toxins. Toxins (Basel) 2019; 11:toxins11110657. [PMID: 31718085 PMCID: PMC6891781 DOI: 10.3390/toxins11110657] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/07/2019] [Accepted: 11/09/2019] [Indexed: 01/08/2023] Open
Abstract
RTX proteins are a large family of polypeptides of mainly Gram-negative origin that are secreted into the extracellular medium by a type I secretion system featuring a non-cleavable C-terminal secretion signal, which is preceded by a variable number of nine-residue tandem repeats. The three-dimensional structure forms a parallel β-roll, where β-strands of two parallel sheets are connected by calcium-binding linkers in such a way that a right-handed spiral is built. The Ca2+ ions are an integral part of the structure, which cannot form without them. The structural determinants of this unique architecture will be reviewed with its conservations and variations together with the implication for secretion and folding of these proteins. The general purpose of the RTX domains appears to act as an internal chaperone that keeps the polypeptide unfolded in the calcium-deprived cytosol and triggers folding in the calcium-rich extracellular medium. A rather recent addition to the structural biology of the RTX toxin is a variant occurring in a large RTX adhesin, where this non-canonical β-roll binds to ice and diatoms.
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Affiliation(s)
- Ulrich Baumann
- Institute of Biochemistry, University of Cologne, Zülpicherstrasse 47, D-50674 Cologne, Germany
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9
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Topologically-guided continuous protein crystallization controls bacterial surface layer self-assembly. Nat Commun 2019; 10:2731. [PMID: 31227690 PMCID: PMC6588578 DOI: 10.1038/s41467-019-10650-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/16/2019] [Indexed: 12/22/2022] Open
Abstract
Many bacteria and most archaea possess a crystalline protein surface layer (S-layer), which surrounds their growing and topologically complicated outer surface. Constructing a macromolecular structure of this scale generally requires localized enzymatic machinery, but a regulatory framework for S-layer assembly has not been identified. By labeling, superresolution imaging, and tracking the S-layer protein (SLP) from C. crescentus, we show that 2D protein self-assembly is sufficient to build and maintain the S-layer in living cells by efficient protein crystal nucleation and growth. We propose a model supported by single-molecule tracking whereby randomly secreted SLP monomers diffuse on the lipopolysaccharide (LPS) outer membrane until incorporated at the edges of growing 2D S-layer crystals. Surface topology creates crystal defects and boundaries, thereby guiding S-layer assembly. Unsupervised assembly poses challenges for therapeutics targeting S-layers. However, protein crystallization as an evolutionary driver rationalizes S-layer diversity and raises the potential for biologically inspired self-assembling macromolecular nanomaterials. Bacteria assemble the surface layer (S-layer), a crystalline protein coat surrounding the curved surface, using protein self-assembly. Here authors image native and purified RsaA, the S-layer protein from C. crescentus, and show that protein crystallization alone is sufficient to assemble and maintain the S-layer in vivo.
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10
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O'Brien DP, Cannella SE, Voegele A, Raoux-Barbot D, Davi M, Douché T, Matondo M, Brier S, Ladant D, Chenal A. Post-translational acylation controls the folding and functions of the CyaA RTX toxin. FASEB J 2019; 33:10065-10076. [PMID: 31226003 DOI: 10.1096/fj.201802442rr] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The adenylate cyclase (CyaA) toxin is a major virulence factor of Bordetella pertussis, the causative agent of whooping cough. CyaA is synthetized as a pro-toxin, pro-CyaA, and converted into its cytotoxic form upon acylation of two lysines. After secretion, CyaA invades eukaryotic cells and produces cAMP, leading to host defense subversion. To gain further insights into the effect of acylation, we compared the functional and structural properties of pro-CyaA and CyaA proteins. HDX-MS results show that the refolding process of both proteins upon progressive urea removal is initiated by calcium binding to the C-terminal RTX domain. We further identified a critical hydrophobic segment, distal from the acylation region, that folds at higher urea concentration in CyaA than in pro-CyaA. Once refolded into monomers, CyaA is more compact and stable than pro-CyaA, due to a complex set of interactions between domains. Our HDX-MS data provide direct evidence that the presence of acyl chains in CyaA induces a significant stabilization of the apolar segments of the hydrophobic domain and of most of the acylation region. We propose a refolding model dependent on calcium and driven by local and distal acylation-dependent interactions within CyaA. Therefore, CyaA acylation is not only critical for cell intoxication, but also for protein refolding into its active conformation. Our data shed light on the complex relationship between post-translational modifications, structural disorder and protein folding. Coupling calcium-binding and acylation-driven folding is likely pertinent for other repeat-in-toxin cytolysins produced by many Gram-negative bacterial pathogens.-O'Brien, D. P., Cannella, S. E., Voegele, A., Raoux-Barbot, D., Davi, M., Douché, T., Matondo, M., Brier, S., Ladant, D., Chenal, A. Post-translational acylation controls the folding and functions of the CyaA RTX toxin.
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Affiliation(s)
- Darragh P O'Brien
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Sara E Cannella
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Alexis Voegele
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France.,Université Paris Diderot Paris VII, Sorbonne Paris Cité, Paris, France
| | - Dorothée Raoux-Barbot
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Marilyne Davi
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Thibaut Douché
- Institut Pasteur, Proteomics Platform, Mass Spectrometry for Biology Unit, USR CNRS 2000, Paris, France
| | - Mariette Matondo
- Institut Pasteur, Proteomics Platform, Mass Spectrometry for Biology Unit, USR CNRS 2000, Paris, France
| | - Sébastien Brier
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France.,Biological NMR Technical Platform, Center for Technological Resources and Research, UMR CNRS 3528, Paris, France
| | - Daniel Ladant
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Alexandre Chenal
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
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11
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Bulutoglu B, Banta S. Calcium-Dependent RTX Domains in the Development of Protein Hydrogels. Gels 2019; 5:E10. [PMID: 30823512 PMCID: PMC6473919 DOI: 10.3390/gels5010010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
The RTX domains found in some pathogenic proteins encode repetitive peptide sequences that reversibly bind calcium and fold into the unique the β-roll secondary structure. Several of these domains have been studied in isolation, yielding key insights into their structure/function relationships. These domains are increasingly being used in protein engineering applications, where the calcium-induced control over structure can be exploited to gain new functions. Here we review recent advances in the use of RTX domains in the creation of calcium responsive biomaterials.
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Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
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12
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Voegele A, Sadi M, Raoux-Barbot D, Douché T, Matondo M, Ladant D, Chenal A. The Adenylate Cyclase (CyaA) Toxin from Bordetella pertussis Has No Detectable Phospholipase A (PLA) Activity In Vitro. Toxins (Basel) 2019; 11:toxins11020111. [PMID: 30781809 PMCID: PMC6409671 DOI: 10.3390/toxins11020111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/11/2019] [Indexed: 12/11/2022] Open
Abstract
The adenylate cyclase (CyaA) toxin produced in Bordetella pertussis is the causative agent of whooping cough. CyaA exhibits the remarkable capacity to translocate its N-terminal adenyl cyclase domain (ACD) directly across the plasma membrane into the cytosol of eukaryotic cells. Once translocated, calmodulin binds and activates ACD, leading to a burst of cAMP that intoxicates the target cell. Previously, Gonzalez-Bullon et al. reported that CyaA exhibits a phospholipase A activity that could destabilize the membrane to facilitate ACD membrane translocation. However, Bumba and collaborators lately reported that they could not replicate these results. To clarify this controversy, we assayed the putative PLA activity of two CyaA samples purified in two different laboratories by using two distinct fluorescent probes reporting either PLA2 or both PLA1 and PLA2 activities, as well as in various experimental conditions (i.e., neutral or negatively charged membranes in different buffers.) However, we could not detect any PLA activity in these CyaA batches. Thus, our data independently confirm that CyaA does not possess any PLA activity.
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Affiliation(s)
- Alexis Voegele
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
- Université Paris Diderot Paris VII, 75013 Paris, France.
| | - Mirko Sadi
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
| | - Dorothée Raoux-Barbot
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
| | - Thibaut Douché
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS 2000, CEDEX 15, 75724 Paris, France.
| | - Mariette Matondo
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS 2000, CEDEX 15, 75724 Paris, France.
| | - Daniel Ladant
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
| | - Alexandre Chenal
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
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13
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Voegele A, O'Brien DP, Subrini O, Sapay N, Cannella SE, Enguéné VYN, Hessel A, Karst J, Hourdel V, Perez ACS, Davi M, Veneziano R, Chopineau J, Vachette P, Durand D, Brier S, Ladant D, Chenal A. Translocation and calmodulin-activation of the adenylate cyclase toxin (CyaA) of Bordetella pertussis. Pathog Dis 2018; 76:5188676. [PMID: 30452651 DOI: 10.1093/femspd/fty085] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/16/2018] [Indexed: 01/19/2023] Open
Abstract
The adenylate cyclase toxin (CyaA) is a multi-domain protein secreted by Bordetella pertussis, the causative agent of whooping cough. CyaA is involved in the early stages of respiratory tract colonization by Bordetella pertussis. CyaA is produced and acylated in the bacteria, and secreted via a dedicated secretion system. The cell intoxication process involves a unique mechanism of transport of the CyaA toxin catalytic domain (ACD) across the plasma membrane of eukaryotic cells. Once translocated, ACD binds to and is activated by calmodulin and produces high amounts of cAMP, subverting the physiology of eukaryotic cells. Here, we review our work on the identification and characterization of a critical region of CyaA, the translocation region, required to deliver ACD into the cytosol of target cells. The translocation region contains a segment that exhibits membrane-active properties, i.e. is able to fold upon membrane interaction and permeabilize lipid bilayers. We proposed that this region is required to locally destabilize the membrane, decreasing the energy required for ACD translocation. To further study the translocation process, we developed a tethered bilayer lipid membrane (tBLM) design that recapitulate the ACD transport across a membrane separating two hermetic compartments. We showed that ACD translocation is critically dependent on calcium, membrane potential, CyaA acylation and on the presence of calmodulin in the trans compartment. Finally, we describe how calmodulin-binding triggers key conformational changes in ACD, leading to its activation and production of supraphysiological concentrations of cAMP.
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Affiliation(s)
- Alexis Voegele
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France.,Université Paris Diderot Paris VII, 75013 Paris, France
| | - Darragh P O'Brien
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France.,University of Oxford, United Kingdom
| | - Orso Subrini
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Nicolas Sapay
- Bioaster Technology Research Institute, 69007 Lyon, France
| | - Sara E Cannella
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France.,University of Oxford, United Kingdom
| | - Véronique Yvette Ntsogo Enguéné
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Audrey Hessel
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Johanna Karst
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Véronique Hourdel
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Ana Cristina Sotomayor Perez
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Marilyne Davi
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Rémi Veneziano
- ICGM, UMR 5253 Univ Montpellier, CNRS, ENSCM, Montpellier 34095, France.,Department of Bioengineering, Volgenau School of Engineering, George Mason University, Fairfax, VA 22030-4422, USA
| | - Joel Chopineau
- ICGM, UMR 5253 Univ Montpellier, CNRS, ENSCM, Montpellier 34095, France
| | - Patrice Vachette
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette cedex 91198, France
| | - Dominique Durand
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette cedex 91198, France
| | - Sébastien Brier
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Daniel Ladant
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Alexandre Chenal
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
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14
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Brown AC, Boesze-Battaglia K, Balashova NV, Mas Gómez N, Speicher K, Tang HY, Duszyk ME, Lally ET. Membrane localization of the Repeats-in-Toxin (RTX) Leukotoxin (LtxA) produced by Aggregatibacter actinomycetemcomitans. PLoS One 2018; 13:e0205871. [PMID: 30335797 PMCID: PMC6193665 DOI: 10.1371/journal.pone.0205871] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/02/2018] [Indexed: 12/31/2022] Open
Abstract
The oral bacterium, Aggregatibacter actinomycetemcomitans, which is associated with localized aggressive periodontitis, as well as systemic infections including endocarditis, produces numerous virulence factors, including a repeats-in-toxin (RTX) protein called leukotoxin (LtxA), which kills human immune cells. The strains of A. actinomycetemcomitans most closely associated with disease have been shown to produce the most LtxA, suggesting that LtxA plays a significant role in the virulence of this organism. LtxA, like many of the RTX toxins, can be divided into four functional domains: an N-terminal hydrophobic domain, which contains a significant fraction of hydrophobic residues and has been proposed to play a role in the membrane interaction of the toxin; the central domain, which contains two lysine residues that are the sites of post-translational acylation; the repeat domain that is characteristic of the RTX toxins, and a C-terminal domain thought to be involved in secretion. In its initial interaction with the host cell, LtxA must bind to both cholesterol and an integrin receptor, lymphocyte function-associated antigen-1 (LFA-1). While both interactions are essential for toxicity, the domains of LtxA involved remain unknown. We therefore undertook a series of experiments, including tryptophan quenching and trypsin digestion, to characterize the structure of LtxA upon interaction with membranes of various lipid compositions. Our results demonstrate that LtxA adopts a U-shaped conformation in the membrane, with the N- and C-terminal domains residing outside of the membrane.
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Affiliation(s)
- Angela C. Brown
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Nataliya V. Balashova
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Nestor Mas Gómez
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Kaye Speicher
- Wistar Institute, Philadelphia, PA, United States of America
| | - Hsin-Yao Tang
- Wistar Institute, Philadelphia, PA, United States of America
| | - Margaret E. Duszyk
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Edward T. Lally
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
- * E-mail:
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15
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Mendoza-Hoffmann F, Zarco-Zavala M, Ortega R, García-Trejo JJ. Control of rotation of the F1FO-ATP synthase nanomotor by an inhibitory α-helix from unfolded ε or intrinsically disordered ζ and IF1 proteins. J Bioenerg Biomembr 2018; 50:403-424. [DOI: 10.1007/s10863-018-9773-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/13/2018] [Indexed: 12/14/2022]
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16
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O'Brien DP, Perez ACS, Karst J, Cannella SE, Enguéné VYN, Hessel A, Raoux-Barbot D, Voegele A, Subrini O, Davi M, Guijarro JI, Raynal B, Baron B, England P, Hernandez B, Ghomi M, Hourdel V, Malosse C, Chamot-Rooke J, Vachette P, Durand D, Brier S, Ladant D, Chenal A. Calcium-dependent disorder-to-order transitions are central to the secretion and folding of the CyaA toxin of Bordetella pertussis, the causative agent of whooping cough. Toxicon 2018; 149:37-44. [DOI: 10.1016/j.toxicon.2018.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/20/2017] [Accepted: 01/10/2018] [Indexed: 02/07/2023]
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17
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Calcium-Binding Proteins with Disordered Structure and Their Role in Secretion, Storage, and Cellular Signaling. Biomolecules 2018; 8:biom8020042. [PMID: 29921816 PMCID: PMC6022996 DOI: 10.3390/biom8020042] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/12/2018] [Accepted: 06/14/2018] [Indexed: 12/19/2022] Open
Abstract
Calcium is one of the most important second messengers and its intracellular signaling regulates many aspects of cell physiology. Calcium ions, like phosphate ions, are highly charged and thus are able to alter protein conformation upon binding; thereby they constitute key factors in signal transduction. One of the most common calcium-binding structural motifs is the EF-hand, a well-defined helix-loop-helix structural domain, present in many calcium-binding proteins (CBPs). Nonetheless, some CBPs contain non-canonical, disordered motifs, which usually bind calcium with high capacity and low affinity, and which represent a subset of proteins with specific functions, but these functions rarely involve signaling. When compared with phosphorylation-mediated signal transduction, the role of intrinsic disorder in calcium signaling is significantly less prominent and not direct. The list of known examples of intrinsically disordered CBPs is relatively short and the disorder in these examples seems to be linked to secretion and storage. Calcium-sensitive phosphatase calcineurin is an exception, but it represents an example of transient disorder, which is, nevertheless, vital to the functioning of this protein. The underlying reason for the different role of disordered proteins in the two main cellular signaling systems appears to be linked to the gradient of calcium concentration, present in all living cells.
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18
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Membrane-Active Properties of an Amphitropic Peptide from the CyaA Toxin Translocation Region. Toxins (Basel) 2017; 9:toxins9110369. [PMID: 29135925 PMCID: PMC5705984 DOI: 10.3390/toxins9110369] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 12/28/2022] Open
Abstract
The adenylate cyclase toxin CyaA is involved in the early stages of infection by Bordetella pertussis, the causative agent of whooping cough. CyaA intoxicates target cells by a direct translocation of its catalytic domain (AC) across the plasma membrane and produces supraphysiological levels of cAMP, leading to cell death. The molecular process of AC translocation remains largely unknown, however. We have previously shown that deletion of residues 375–485 of CyaA selectively abrogates AC translocation into eukaryotic cells. We further identified within this “translocation region” (TR), P454 (residues 454–484), a peptide that exhibits membrane-active properties, i.e., is able to bind and permeabilize lipid vesicles. Here, we analyze various sequences from CyaA predicted to be amphipatic and show that although several of these peptides can bind membranes and adopt a helical conformation, only the P454 peptide is able to permeabilize membranes. We further characterize the contributions of the two arginine residues of P454 to membrane partitioning and permeabilization by analyzing the peptide variants in which these residues are substituted by different amino acids (e.g., A, K, Q, and E). Our data shows that both arginine residues significantly contribute, although diversely, to the membrane-active properties of P454, i.e., interactions with both neutral and anionic lipids, helix formation in membranes, and disruption of lipid bilayer integrity. These results are discussed in the context of the translocation process of the full-length CyaA toxin.
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19
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Structure-Function Relationships Underlying the Capacity of Bordetella Adenylate Cyclase Toxin to Disarm Host Phagocytes. Toxins (Basel) 2017; 9:toxins9100300. [PMID: 28946636 PMCID: PMC5666347 DOI: 10.3390/toxins9100300] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 01/18/2023] Open
Abstract
Bordetellae, pathogenic to mammals, produce an immunomodulatory adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) that enables them to overcome the innate immune defense of the host. CyaA subverts host phagocytic cells by an orchestrated action of its functional domains, where an extremely catalytically active adenylyl cyclase enzyme is delivered into phagocyte cytosol by a pore-forming repeat-in-toxin (RTX) cytolysin moiety. By targeting sentinel cells expressing the complement receptor 3, known as the CD11b/CD18 (αMβ₂) integrin, CyaA compromises the bactericidal functions of host phagocytes and supports infection of host airways by Bordetellae. Here, we review the state of knowledge on structural and functional aspects of CyaA toxin action, placing particular emphasis on signaling mechanisms by which the toxin-produced 3',5'-cyclic adenosine monophosphate (cAMP) subverts the physiology of phagocytic cells.
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20
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Bulutoglu B, Banta S. Block V RTX Domain of Adenylate Cyclase from Bordetella pertussis: A Conformationally Dynamic Scaffold for Protein Engineering Applications. Toxins (Basel) 2017; 9:E289. [PMID: 28926974 PMCID: PMC5618222 DOI: 10.3390/toxins9090289] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/12/2017] [Accepted: 09/12/2017] [Indexed: 01/27/2023] Open
Abstract
The isolated Block V repeats-in-toxin (RTX) peptide domain of adenylate cyclase (CyaA) from Bordetella pertussis reversibly folds into a β-roll secondary structure upon calcium binding. In this review, we discuss how the conformationally dynamic nature of the peptide is being engineered and employed as a switching mechanism to mediate different protein functions and protein-protein interactions. The peptide has been used as a scaffold for diverse applications including: a precipitation tag for bioseparations, a cross-linking domain for protein hydrogel formation and as an alternative scaffold for biomolecular recognition applications. Proteins and peptides such as the RTX domains that exhibit natural stimulus-responsive behavior are valuable building blocks for emerging synthetic biology applications.
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Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
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21
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Bulutoglu B, Dooley K, Szilvay G, Blenner M, Banta S. Catch and Release: Engineered Allosterically Regulated β-Roll Peptides Enable On/Off Biomolecular Recognition. ACS Synth Biol 2017; 6:1732-1741. [PMID: 28520402 DOI: 10.1021/acssynbio.7b00089] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alternative scaffolds for biomolecular recognition are being developed to overcome some of the limitations associated with immunoglobulin domains. The repeat-in-toxin (RTX) domain is a repeat protein sequence that reversibly adopts the β-roll secondary structure motif specifically upon calcium binding. This conformational change was exploited for controlled biomolecular recognition. Using ribosome display, an RTX peptide library was selected to identify binders to a model protein, lysozyme, exclusively in the folded state of the peptide. Several mutants were identified with low micromolar dissociation constants. After concatenation of the mutants, a 500-fold increase in the overall affinity for lysozyme was achieved leading to a peptide with an apparent dissociation constant of 65 nM. This mutant was immobilized for affinity chromatography experiments, and the on/off nature of the molecular recognition was demonstrated as the target is captured from a mixture in the presence of calcium and is released in the absence of calcium as the RTX peptides lose their β-roll structure. This work presents the design of a new stimulus-responsive scaffold that can be used for environmentally responsive specific molecular recognition and self-assembly.
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Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Kevin Dooley
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Géza Szilvay
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Mark Blenner
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
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22
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DeForte S, Uversky VN. Not an exception to the rule: the functional significance of intrinsically disordered protein regions in enzymes. MOLECULAR BIOSYSTEMS 2017; 13:463-469. [PMID: 28098335 DOI: 10.1039/c6mb00741d] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Intrinsically disordered protein regions (IDPRs) are remarkably common and have unique and important biological functions. Enzymes have long been considered an exception to the rule of protein intrinsic disorder due to the structural requirements for catalysis. Although functionally significant IDPRs have been described in several enzymes, there has been no study quantifying the extent of this phenomenon. We have conducted a multilevel computational analysis of missing regions in X-ray crystal structures in the PDB and predicted disorder in 66 representative proteomes. We found that the fraction of predicted disorder was higher in non-enzymes than enzymes, because non-enzymes were more likely to be fully disordered. However, we also found that transferases, hydrolases and enzymes with multiple assigned functional classifications were similar to non-enzymes in terms of the length of the longest continuous stretch of predicted disorder. Both eukaryotic enzymes and non-enzymes had a greater disorder content than was seen in bacteria. Disorder at the proteome level appears to emerge in response to organismic and functional complexity, and enzymes are not an exception to this rule.
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Affiliation(s)
- Shelly DeForte
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, USA. and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, USA and Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
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23
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Molecular Modeling of the Catalytic Domain of CyaA Deepened the Knowledge of Its Functional Dynamics. Toxins (Basel) 2017; 9:toxins9070199. [PMID: 28672846 PMCID: PMC5535146 DOI: 10.3390/toxins9070199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/16/2022] Open
Abstract
Although CyaA has been studied for over three decades and revealed itself to be a very good prototype for developing various biotechnological applications, only a little is known about its functional dynamics and about the conformational landscape of this protein. Molecular dynamics simulations helped to clarify the view on these points in the following way. First, the model of interaction between AC and calmodulin (CaM) has evolved from an interaction centered on the surface between C-CaM hydrophobic patch and the α helix H of AC, to a more balanced view, in which the C-terminal tail of AC along with the C-CaM Calcium loops play an important role. This role has been confirmed by the reduction of the affinity of AC for calmodulin in the presence of R338, D360 and N347 mutations. In addition, enhanced sampling studies have permitted to propose a representation of the conformational space for the isolated AC. It remains to refine this representation using structural low resolution information measured on the inactive state of AC. Finally, due to a virtual screening study on another adenyl cyclase from Bacillus anthracis, weak inhibitors of AC have been discovered.
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24
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Bulutoglu B, Yang SJ, Banta S. Conditional Network Assembly and Targeted Protein Retention via Environmentally Responsive, Engineered β-Roll Peptides. Biomacromolecules 2017; 18:2139-2145. [PMID: 28578565 DOI: 10.1021/acs.biomac.7b00457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, Room 801, New York, New York 10027, United States
| | - Sarah J. Yang
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, Room 801, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, Room 801, New York, New York 10027, United States
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25
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Herrmann J, Jabbarpour F, Bargar PG, Nomellini JF, Li PN, Lane TJ, Weiss TM, Smit J, Shapiro L, Wakatsuki S. Environmental Calcium Controls Alternate Physical States of the Caulobacter Surface Layer. Biophys J 2017; 112:1841-1851. [PMID: 28494955 PMCID: PMC5425405 DOI: 10.1016/j.bpj.2017.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/28/2017] [Accepted: 04/06/2017] [Indexed: 11/23/2022] Open
Abstract
Surface layers (S-layers) are paracrystalline, proteinaceous structures found in most archaea and many bacteria. Often the outermost cell envelope component, S-layers serve diverse functions including aiding pathogenicity and protecting against predators. We report that the S-layer of Caulobacter crescentus exhibits calcium-mediated structural plasticity, switching irreversibly between an amorphous aggregate state and the crystalline state. This finding invalidates the common assumption that S-layers serve only as static wall-like structures. In vitro, the Caulobacter S-layer protein, RsaA, enters the aggregate state at physiological temperatures and low divalent calcium ion concentrations. At higher concentrations, calcium ions stabilize monomeric RsaA, which can then transition to the two-dimensional crystalline state. Caulobacter requires micromolar concentrations of calcium for normal growth and development. Without an S-layer, Caulobacter is even more sensitive to changes in environmental calcium concentration. Therefore, this structurally dynamic S-layer responds to environmental conditions as an ion sensor and protects Caulobacter from calcium deficiency stress, a unique mechanism of bacterial adaptation. These findings provide a biochemical and physiological basis for RsaA's calcium-binding behavior, which extends far beyond calcium's commonly accepted role in aiding S-layer biogenesis or oligomerization and demonstrates a connection to cellular fitness.
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Affiliation(s)
- Jonathan Herrmann
- Department of Structural Biology, Stanford University, Stanford, California; Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California.
| | - Fatemeh Jabbarpour
- Department of Structural Biology, Stanford University, Stanford, California
| | | | - John F Nomellini
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Po-Nan Li
- Department of Electrical Engineering, Stanford University, Stanford, California
| | - Thomas J Lane
- Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California
| | - Thomas M Weiss
- Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California
| | - John Smit
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lucy Shapiro
- Department of Developmental Biology, Stanford University, Stanford, California.
| | - Soichi Wakatsuki
- Department of Structural Biology, Stanford University, Stanford, California; Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California.
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26
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Cannella SE, Ntsogo Enguéné VY, Davi M, Malosse C, Sotomayor Pérez AC, Chamot-Rooke J, Vachette P, Durand D, Ladant D, Chenal A. Stability, structural and functional properties of a monomeric, calcium-loaded adenylate cyclase toxin, CyaA, from Bordetella pertussis. Sci Rep 2017; 7:42065. [PMID: 28186111 PMCID: PMC5301233 DOI: 10.1038/srep42065] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/04/2017] [Indexed: 12/21/2022] Open
Abstract
Bordetella pertussis, the causative agent of whooping cough, secretes an adenylate cyclase toxin, CyaA, which invades eukaryotic cells and alters their physiology by cAMP overproduction. Calcium is an essential cofactor of CyaA, as it is the case for most members of the Repeat-in-ToXins (RTX) family. We show that the calcium-bound, monomeric form of CyaA, hCyaAm, conserves its permeabilization and haemolytic activities, even in a fully calcium-free environment. In contrast, hCyaAm requires sub-millimolar calcium in solution for cell invasion, indicating that free calcium in solution is involved in the CyaA toxin translocation process. We further report the first in solution structural characterization of hCyaAm, as deduced from SAXS, mass spectrometry and hydrodynamic studies. We show that hCyaAm adopts a compact and stable state that can transiently conserve its conformation even in a fully calcium-free environment. Our results therefore suggest that in hCyaAm, the C-terminal RTX-domain is stabilized in a high-affinity calcium-binding state by the N-terminal domains while, conversely, calcium binding to the C-terminal RTX-domain strongly stabilizes the N-terminal regions. Hence, the different regions of hCyaAm appear tightly connected, leading to stabilization effects between domains. The hysteretic behaviour of CyaA in response to calcium is likely shared by other RTX cytolysins.
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Affiliation(s)
- Sara E. Cannella
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Marilyne Davi
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Christian Malosse
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Julia Chamot-Rooke
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Patrice Vachette
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Daniel Ladant
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Alexandre Chenal
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
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27
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DeForte S, Uversky VN. Order, Disorder, and Everything in Between. Molecules 2016; 21:molecules21081090. [PMID: 27548131 PMCID: PMC6274243 DOI: 10.3390/molecules21081090] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 02/04/2023] Open
Abstract
In addition to the “traditional” proteins characterized by the unique crystal-like structures needed for unique functions, it is increasingly recognized that many proteins or protein regions (collectively known as intrinsically disordered proteins (IDPs) and intrinsically disordered protein regions (IDPRs)), being biologically active, do not have a specific 3D-structure in their unbound states under physiological conditions. There are also subtler categories of disorder, such as conditional (or dormant) disorder and partial disorder. Both the ability of a protein/region to fold into a well-ordered functional unit or to stay intrinsically disordered but functional are encoded in the amino acid sequence. Structurally, IDPs/IDPRs are characterized by high spatiotemporal heterogeneity and exist as dynamic structural ensembles. It is important to remember, however, that although structure and disorder are often treated as binary states, they actually sit on a structural continuum.
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Affiliation(s)
- Shelly DeForte
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
- USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
- Laboratory of Structural Dynamics, Stability and Folding of Proteins, Institute of Cytology, Russian Academy of Sciences, St. Petersburg 194064, Russia.
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28
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Hourdel V, Volant S, O'Brien DP, Chenal A, Chamot-Rooke J, Dillies MA, Brier S. MEMHDX: an interactive tool to expedite the statistical validation and visualization of large HDX-MS datasets. Bioinformatics 2016; 32:3413-3419. [PMID: 27412089 PMCID: PMC5181559 DOI: 10.1093/bioinformatics/btw420] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 06/21/2016] [Accepted: 06/27/2016] [Indexed: 11/17/2022] Open
Abstract
Motivation: With the continued improvement of requisite mass spectrometers and UHPLC systems, Hydrogen/Deuterium eXchange Mass Spectrometry (HDX-MS) workflows are rapidly evolving towards the investigation of more challenging biological systems, including large protein complexes and membrane proteins. The analysis of such extensive systems results in very large HDX-MS datasets for which specific analysis tools are required to speed up data validation and interpretation. Results: We introduce a web application and a new R-package named ‘MEMHDX’ to help users analyze, validate and visualize large HDX-MS datasets. MEMHDX is composed of two elements. A statistical tool aids in the validation of the results by applying a mixed-effects model for each peptide, in each experimental condition, and at each time point, taking into account the time dependency of the HDX reaction and number of independent replicates. Two adjusted P-values are generated per peptide, one for the ‘Change in dynamics’ and one for the ‘Magnitude of ΔD’, and are used to classify the data by means of a ‘Logit’ representation. A user-friendly interface developed with Shiny by RStudio facilitates the use of the package. This interactive tool allows the user to easily and rapidly validate, visualize and compare the relative deuterium incorporation on the amino acid sequence and 3D structure, providing both spatial and temporal information. Availability and Implementation: MEMHDX is freely available as a web tool at the project home page http://memhdx.c3bi.pasteur.fr Contact:marie-agnes.dillies@pasteur.fr or sebastien.brier@pasteur.fr Supplementary information:Supplementary data is available at Bioinformatics online.
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Affiliation(s)
- Véronique Hourdel
- Department of Chemistry and Structural Biology, Institut Pasteur, UMR CNRS, Paris 3528, France
| | - Stevenn Volant
- Hub Bioinformatique Et Biostatistique, Institut Pasteur, C3bi, USR 3756 IP CNRS Paris 3528, France
| | - Darragh P O'Brien
- Department of Chemistry and Structural Biology, Institut Pasteur, UMR CNRS, Paris 3528, France
| | - Alexandre Chenal
- Department of Chemistry and Structural Biology, Institut Pasteur, UMR CNRS, Paris 3528, France
| | - Julia Chamot-Rooke
- Department of Chemistry and Structural Biology, Institut Pasteur, UMR CNRS, Paris 3528, France
| | - Marie-Agnès Dillies
- Hub Bioinformatique Et Biostatistique, Institut Pasteur, C3bi, USR 3756 IP CNRS Paris 3528, France
| | - Sébastien Brier
- Department of Chemistry and Structural Biology, Institut Pasteur, UMR CNRS, Paris 3528, France
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29
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Bioinformatical parsing of folding-on-binding proteins reveals their compositional and evolutionary sequence design. Sci Rep 2015; 5:18586. [PMID: 26678310 PMCID: PMC4683461 DOI: 10.1038/srep18586] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/20/2015] [Indexed: 12/29/2022] Open
Abstract
Intrinsic disorder occurs when (part of) a protein remains unfolded during normal functioning. Intrinsically-disordered regions can contain segments that ‘fold on binding’ to another molecule. Here, we perform bioinformatical parsing of human ‘folding-on-binding’ (FB) proteins, into four subsets: Ordered regions, FB regions, Disordered regions that surround FB regions (‘Disordered-around-FB’), and Other-Disordered regions. We examined the composition and evolutionary behaviour (across vertebrate orthologs) of these subsets. From a convergence of three separate analyses, we find that for hydrophobicity, Ordered regions segregate from the other subsets, but the Ordered and FB regions group together as highly conserved, and the Disordered-around-FB and Other-Disordered regions as less conserved (with a lesser significant difference between Ordered and FB regions). FB regions are highly-conserved with net positive charge, whereas Disordered-around-FB have net negative charge and are relatively less hydrophobic than FB regions. Indeed, these Disordered-around-FB regions are excessively hydrophilic compared to other disordered regions generally. We describe how our results point towards a possible compositionally-based steering mechanism of folding-on-binding.
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30
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Gavin HE, Satchell KJF. MARTX toxins as effector delivery platforms. Pathog Dis 2015; 73:ftv092. [PMID: 26472741 DOI: 10.1093/femspd/ftv092] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2015] [Indexed: 12/14/2022] Open
Abstract
Bacteria frequently manipulate their host environment via delivery of microbial 'effector' proteins to the cytosol of eukaryotic cells. In the case of the multifunctional autoprocessing repeats-in-toxins (MARTX) toxin, this phenomenon is accomplished by a single, >3500 amino acid polypeptide that carries information for secretion, translocation, autoprocessing and effector activity. MARTX toxins are secreted from bacteria by dedicated Type I secretion systems. The released MARTX toxins form pores in target eukaryotic cell membranes for the delivery of up to five cytopathic effectors, each of which disrupts a key cellular process. Targeted cellular processes include modulation or modification of small GTPases, manipulation of host cell signaling and disruption of cytoskeletal integrity. More recently, MARTX toxins have been shown to be capable of heterologous protein translocation. Found across multiple bacterial species and genera--frequently in pathogens lacking Type 3 or Type 4 secretion systems--MARTX toxins in multiple cases function as virulence factors. Innovative research at the intersection of toxin biology and bacterial genetics continues to elucidate the intricacies of the toxin as well as the cytotoxic mechanisms of its diverse effector collection.
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Affiliation(s)
- Hannah E Gavin
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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31
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O'Brien DP, Hernandez B, Durand D, Hourdel V, Sotomayor-Pérez AC, Vachette P, Ghomi M, Chamot-Rooke J, Ladant D, Brier S, Chenal A. Structural models of intrinsically disordered and calcium-bound folded states of a protein adapted for secretion. Sci Rep 2015; 5:14223. [PMID: 26374675 PMCID: PMC4642704 DOI: 10.1038/srep14223] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/20/2015] [Indexed: 01/28/2023] Open
Abstract
Many Gram-negative bacteria use Type I secretion systems, T1SS, to secrete virulence factors that contain calcium-binding Repeat-in-ToXin (RTX) motifs. Here, we present structural models of an RTX protein, RD, in both its intrinsically disordered calcium-free Apo-state and its folded calcium-bound Holo-state. Apo-RD behaves as a disordered polymer chain comprising several statistical elements that exhibit local rigidity with residual secondary structure. Holo-RD is a folded multi-domain protein with an anisometric shape. RTX motifs thus appear remarkably adapted to the structural and mechanistic constraints of the secretion process. In the low calcium environment of the bacterial cytosol, Apo-RD is an elongated disordered coil appropriately sized for transport through the narrow secretion machinery. The progressive folding of Holo-RD in the extracellular calcium-rich environment as it emerges form the T1SS may then favor its unidirectional export through the secretory channel. This process is relevant for hundreds of bacterial species producing virulent RTX proteins.
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Affiliation(s)
- Darragh P O'Brien
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Belen Hernandez
- Sorbonne Paris Cité, Université Paris 13, Groupe de Biophysique Moléculaire, UFR Santé-Médecine-Biologie Humaine, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Véronique Hourdel
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Patrice Vachette
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Mahmoud Ghomi
- Sorbonne Paris Cité, Université Paris 13, Groupe de Biophysique Moléculaire, UFR Santé-Médecine-Biologie Humaine, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France
| | - Julia Chamot-Rooke
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Daniel Ladant
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Sébastien Brier
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Alexandre Chenal
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
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32
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Distinct roles of the repeat-containing regions and effector domains of the Vibrio vulnificus multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin. mBio 2015; 6:mBio.00324-15. [PMID: 25827415 PMCID: PMC4453568 DOI: 10.1128/mbio.00324-15] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Vibrio vulnificus is a seafood-borne pathogen that destroys the intestinal epithelium, leading to rapid bacterial dissemination and death. The most important virulence factor is the multifunctional-autoprocessing repeats-in-toxin (MARTX) toxin comprised of effector domains in the center region flanked by long repeat-containing regions which are well conserved among MARTX toxins and predicted to translocate effector domains. Here, we examined the role of the repeat-containing regions using a modified V. vulnificus MARTX (MARTXVv) toxin generated by replacing all the internal effector domains with β-lactamase (Bla). Bla activity was detected in secretions from the bacterium and also in the cytosol of intoxicated epithelial cells. The modified MARTXVv toxin without effector domains retained its necrotic activity but lost its cell-rounding activity. Further, deletion of the carboxyl-terminal repeat-containing region blocked toxin secretion from the bacterium. Deletion of the amino-terminal repeat-containing region had no effect on secretion but completely abolished translocation and necrosis. Neither secretion nor translocation was affected by enzymatically inactivating the cysteine protease domain of the toxin. These data demonstrate that the amino-terminal and carboxyl-terminal repeat-containing regions of the MARTXVv toxin are necessary and sufficient for the delivery of effector domains and epithelial cell lysis in vitro but that effector domains are required for other cytopathic functions. Furthermore, Ca2+-dependent secretion of the modified MARTXVv toxin suggests that nonclassical RTX-like repeats found in the carboxyl-terminal repeat-containing region are functionally similar to classical RTX repeats found in other RTX proteins. Up to 95% of deaths from seafood-borne infections in the United States are due solely to one pathogen, V. vulnificus. Among its various virulence factors, the MARTXVv toxin has been characterized as a critical exotoxin for successful pathogenesis of V. vulnificus in mouse infection models. Similarly to MARTX toxins of other pathogens, MARTXVv toxin is comprised of repeat-containing regions, central effector domains, and an autoprocessing cysteine protease domain. Yet how each of these regions contributes to essential activities of the toxins has not been fully identified for any of MARTX toxins. Using modified MARTXVv toxin fused with β-lactamase as a reporter enzyme, the portion(s) responsible for toxin secretion from bacteria, effector domain translocation into host cells, rapid host cell rounding, and necrotic host cell death was identified. The results are relevant for understanding how MARTXVv toxin serves as both a necrotic pore-forming toxin and an effector delivery platform.
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