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Nagel AS, Vetrova OS, Rudenko NV, Karatovskaya AP, Zamyatina AV, Andreeva-Kovalevskaya ZI, Salyamov VI, Egorova NA, Siunov AV, Ivanova TD, Boziev KM, Brovko FA, Solonin AS. A High-Homology Region Provides the Possibility of Detecting β-Barrel Pore-Forming Toxins from Various Bacterial Species. Int J Mol Sci 2024; 25:5327. [PMID: 38791367 PMCID: PMC11120785 DOI: 10.3390/ijms25105327] [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: 03/16/2024] [Revised: 04/12/2024] [Accepted: 04/16/2024] [Indexed: 05/26/2024] Open
Abstract
The pathogenicity of many bacteria, including Bacillus cereus and Staphylococcus aureus, depends on pore-forming toxins (PFTs), which cause the lysis of host cells by forming pores in the membranes of eukaryotic cells. Bioinformatic analysis revealed a region homologous to the Lys171-Gly250 sequence in hemolysin II (HlyII) from B. cereus in over 600 PFTs, which we designated as a "homologous peptide". Three β-barrel PFTs were used for a detailed comparative analysis. Two of them-HlyII and cytotoxin K2 (CytK2)-are synthesized in Bacillus cereus sensu lato; the third, S. aureus α-toxin (Hla), is the most investigated representative of the family. Protein modeling showed certain amino acids of the homologous peptide to be located on the surface of the monomeric forms of these β-barrel PFTs. We obtained monoclonal antibodies against both a cloned homologous peptide and a 14-membered synthetic peptide, DSFNTFYGNQLFMK, as part of the homologous peptide. The HlyII, CytK2, and Hla regions recognized by the obtained antibodies, as well as an antibody capable of suppressing the hemolytic activity of CytK2, were identified in the course of this work. Antibodies capable of recognizing PFTs of various origins can be useful tools for both identification and suppression of the cytolytic activity of PFTs.
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Affiliation(s)
- Alexey S. Nagel
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.S.N.); (Z.I.A.-K.); (V.I.S.); (A.V.S.); (T.D.I.); (A.S.S.)
| | - Olesya S. Vetrova
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (O.S.V.); (A.P.K.); (A.V.Z.); (K.M.B.); (F.A.B.)
| | - Natalia V. Rudenko
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (O.S.V.); (A.P.K.); (A.V.Z.); (K.M.B.); (F.A.B.)
| | - Anna P. Karatovskaya
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (O.S.V.); (A.P.K.); (A.V.Z.); (K.M.B.); (F.A.B.)
| | - Anna V. Zamyatina
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (O.S.V.); (A.P.K.); (A.V.Z.); (K.M.B.); (F.A.B.)
| | - Zhanna I. Andreeva-Kovalevskaya
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.S.N.); (Z.I.A.-K.); (V.I.S.); (A.V.S.); (T.D.I.); (A.S.S.)
| | - Vadim I. Salyamov
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.S.N.); (Z.I.A.-K.); (V.I.S.); (A.V.S.); (T.D.I.); (A.S.S.)
| | - Nadezhda A. Egorova
- Federal State Budgetary Educational Institution of Higher Education “Ryazan State University Named for S.A. Yesenin”, 46 st. Svobody, 390000 Ryazan, Ryazan Region, Russia;
| | - Alexander V. Siunov
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.S.N.); (Z.I.A.-K.); (V.I.S.); (A.V.S.); (T.D.I.); (A.S.S.)
| | - Tatiana D. Ivanova
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.S.N.); (Z.I.A.-K.); (V.I.S.); (A.V.S.); (T.D.I.); (A.S.S.)
| | - Khanafi M. Boziev
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (O.S.V.); (A.P.K.); (A.V.Z.); (K.M.B.); (F.A.B.)
| | - Fedor A. Brovko
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (O.S.V.); (A.P.K.); (A.V.Z.); (K.M.B.); (F.A.B.)
| | - Alexander S. Solonin
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.S.N.); (Z.I.A.-K.); (V.I.S.); (A.V.S.); (T.D.I.); (A.S.S.)
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Rudenko NV, Nagel AS, Melnik BS, Karatovskaya AP, Vetrova OS, Zamyatina AV, Andreeva-Kovalevskaya ZI, Siunov AV, Shlyapnikov MG, Brovko FA, Solonin AS. Utilizing Extraepitopic Amino Acid Substitutions to Define Changes in the Accessibility of Conformational Epitopes of the Bacillus cereus HlyII C-Terminal Domain. Int J Mol Sci 2023; 24:16437. [PMID: 38003626 PMCID: PMC10671226 DOI: 10.3390/ijms242216437] [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: 10/10/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Hemolysin II (HlyII)-one of the pathogenic factors of Bacillus cereus, a pore-forming β-barrel toxin-possesses a C-terminal extension of 94 amino acid residues, designated as the C-terminal domain of HlyII (HlyIICTD), which plays an important role in the functioning of the toxin. Our previous work described a monoclonal antibody (HlyIIC-20), capable of strain-specific inhibition of hemolysis caused by HlyII, and demonstrated the dependence of the efficiency of hemolysis on the presence of proline at position 324 in HlyII outside the conformational antigenic determinant. In this work, we studied 16 mutant forms of HlyIICTD. Each of the mutations, obtained via multiple site-directed mutagenesis leading to the replacement of amino acid residues lying on the surface of the 3D structure of HlyIICTD, led to a decrease in the interaction of HlyIIC-20 with the mutant form of the protein. Changes in epitope structure confirm the high conformational mobility of HlyIICTD required for the functioning of HlyII. Comparison of the effect of the introduced mutations on the effectiveness of interactions between HlyIICTD and HlyIIC-20 and a control antibody recognizing a non-overlapping epitope enabled the identification of the amino acid residues N339 and K340, included in the conformational antigenic determinant recognized by HlyIIC-20.
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Affiliation(s)
- Natalia V Rudenko
- Pushchino Branch, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Alexey S Nagel
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, FRC Pushchino Scientific Centre of Biological Research, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Bogdan S Melnik
- Pushchino Branch, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
- Institute of Protein Research, Russian Academy of Sciences, 4 Institutskaya Street, 142290 Pushchino, Moscow Region, Russia
| | - Anna P Karatovskaya
- Pushchino Branch, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Olesya S Vetrova
- Pushchino Branch, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Anna V Zamyatina
- Pushchino Branch, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Zhanna I Andreeva-Kovalevskaya
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, FRC Pushchino Scientific Centre of Biological Research, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Alexander V Siunov
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, FRC Pushchino Scientific Centre of Biological Research, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Mikhail G Shlyapnikov
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, FRC Pushchino Scientific Centre of Biological Research, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Fedor A Brovko
- Pushchino Branch, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Alexander S Solonin
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, FRC Pushchino Scientific Centre of Biological Research, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
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The C-terminal domain of Bacillus cereus hemolysin II oligomerizes by itself in the presence of cell membranes to form ion channels. Int J Biol Macromol 2022; 200:416-427. [PMID: 35041890 DOI: 10.1016/j.ijbiomac.2022.01.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/17/2021] [Accepted: 01/04/2022] [Indexed: 12/16/2022]
Abstract
Bacillus cereus hemolysin II, a pore-forming β-barrel toxin (HlyII), has a C-terminal extension of 94 amino acid residues, designated as the C-terminal domain of HlyII (HlyIICTD). HlyIICTD is capable of forming oligomers in aqueous solutions. Oligomerization of HlyIICTD significantly increased in the presence of erythrocytes and liposomes. Its affinity for erythrocytes of various origins differed insignificantly but was noticeably higher for T-cells. HlyIICTD destroyed THP-1 monocytes and J774 macrophages, acted most effectively on Jurkat T-lymphocytes and had virtually no impact on B-cell lines. HlyIICTD was able to form ion-conducting channels on an artificial bilayer membrane.
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Nagel AS, Andreeva-Kovalevskaya ZI, Siunov AV, Nagornykh MO, Zakharova MV, Solonin AS. Transcription of the hlyIIR Gene of Bacillus cereus. RUSS J GENET+ 2021. [DOI: 10.1134/s1022795421060077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Kaplan AR, Olson R, Alexandrescu AT. Protein yoga: Conformational versatility of the Hemolysin II C-terminal domain detailed by NMR structures for multiple states. Protein Sci 2021; 30:990-1005. [PMID: 33733504 DOI: 10.1002/pro.4066] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/10/2021] [Accepted: 03/13/2021] [Indexed: 11/05/2022]
Abstract
The C-terminal domain of Bacillus cereus hemolysin II (HlyIIC), stabilizes the trans-membrane-pore formed by the HlyII toxin and may aid in target cell recognition. Initial efforts to determine the NMR structure of HlyIIC were hampered by cis/trans isomerization about the single proline at position 405 that leads to doubling of NMR resonances. We used the mutant P405M-HlyIIC that eliminates the cis proline to determine the NMR structure of the domain, which revealed a novel fold. Here, we extend earlier studies to the NMR structure determination of the cis and trans states of WT-HlyIIC that exist simultaneously in solution. The primary structural differences between the cis and trans states are in the loop that contains P405, and structurally adjacent loops. Thermodynamic linkage analysis shows that at 25 C the cis proline, which already has a large fraction of 20% in the unfolded protein, increases to 50% in the folded state due to coupling with the global stability of the domain. The P405M or P405A substitutions eliminate heterogeneity due to proline isomerization but lead to the formation of a new dimeric species. The NMR structure of the dimer shows that it is formed through domain-swapping of strand β5, the last segment of secondary structure following P405. The presence of P405 in WT-HlyIIC strongly disfavors the dimer compared to the P405M-HlyIIC or P405A-HlyIIC mutants. The WT proline may thus act as a "gatekeeper," warding off aggregative misfolding.
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Affiliation(s)
- Anne R Kaplan
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
| | - Rich Olson
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut, USA
| | - Andrei T Alexandrescu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut, USA
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The Food Poisoning Toxins of Bacillus cereus. Toxins (Basel) 2021; 13:toxins13020098. [PMID: 33525722 PMCID: PMC7911051 DOI: 10.3390/toxins13020098] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/14/2021] [Accepted: 01/25/2021] [Indexed: 12/13/2022] Open
Abstract
Bacillus cereus is a ubiquitous soil bacterium responsible for two types of food-associated gastrointestinal diseases. While the emetic type, a food intoxication, manifests in nausea and vomiting, food infections with enteropathogenic strains cause diarrhea and abdominal pain. Causative toxins are the cyclic dodecadepsipeptide cereulide, and the proteinaceous enterotoxins hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe) and cytotoxin K (CytK), respectively. This review covers the current knowledge on distribution and genetic organization of the toxin genes, as well as mechanisms of enterotoxin gene regulation and toxin secretion. In this context, the exceptionally high variability of toxin production between single strains is highlighted. In addition, the mode of action of the pore-forming enterotoxins and their effect on target cells is described in detail. The main focus of this review are the two tripartite enterotoxin complexes Hbl and Nhe, but the latest findings on cereulide and CytK are also presented, as well as methods for toxin detection, and the contribution of further putative virulence factors to the diarrheal disease.
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Zamyatina AV, Rudenko NV, Karatovskaya AP, Shepelyakovskaya AO, Siunov AV, Andreeva-Kovalevskaya ZI, Nagel AS, Salyamov VI, Kolesnikov AS, Brovko FA, Solonin AS. Monoclonal Antibody HlyIIC‑15 to C-End Domain HlyII B. cereus Interacts with the Trombin Recognition Site. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020; 46:1214-1220. [PMID: 33390685 PMCID: PMC7768993 DOI: 10.1134/s1068162020060382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 11/23/2022]
Abstract
Among the panel of monoclonal antibodies to the recombinant protein HlyIICTD Bacillus cereus an antibody was found capable of forming an immune complex with a thrombin recognition region, the amino acid sequence of which is located inside the recombinant HlyIICTD. Localization of the epitope was carried out using peptide phage display methods, as well as enzyme immunoassay and immunoblotting for interaction with recombinant proteins, either containing or not containing individual components HlyIICTD. The identified epitope is located in the region of the thrombin site and retains the ability to interact with the antibody after the proteolyotic attack of the protein by thrombin.
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Affiliation(s)
- A. V. Zamyatina
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
- Pushchino State Natural Science Institute, Pushchino, Moscow oblast 142290 Russia
| | - N. V. Rudenko
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. P. Karatovskaya
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. O. Shepelyakovskaya
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. V. Siunov
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - Zh. I. Andreeva-Kovalevskaya
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. S. Nagel
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - V. I. Salyamov
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - A. S. Kolesnikov
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
| | - F. A. Brovko
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Pushchino Branch, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
- Pushchino State Natural Science Institute, Pushchino, Moscow oblast 142290 Russia
| | - A. S. Solonin
- Scryabin Institute of Biochemistry and Physiology of Microorganisms, Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Moscow oblast 142290 Russia
- Pushchino State Natural Science Institute, Pushchino, Moscow oblast 142290 Russia
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Rudenko N, Nagel A, Zamyatina A, Karatovskaya A, Salyamov V, Andreeva-Kovalevskaya Z, Siunov A, Kolesnikov A, Shepelyakovskaya A, Boziev K, Melnik B, Brovko F, Solonin A. A Monoclonal Antibody against the C-Terminal Domain of Bacillus cereus Hemolysin II Inhibits HlyII Cytolytic Activity. Toxins (Basel) 2020; 12:E806. [PMID: 33352744 PMCID: PMC7767301 DOI: 10.3390/toxins12120806] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/19/2020] [Accepted: 12/16/2020] [Indexed: 01/13/2023] Open
Abstract
Bacillus cereus is the fourth most common cause of foodborne illnesses that produces a variety of pore-forming proteins as the main pathogenic factors. B. cereus hemolysin II (HlyII), belonging to pore-forming β-barrel toxins, has a C-terminal extension of 94 amino acid residues designated as HlyIICTD. An analysis of a panel of monoclonal antibodies to the recombinant HlyIICTD protein revealed the ability of the antibody HlyIIC-20 to inhibit HlyII hemolysis. A conformational epitope recognized by HlyIIC-20 was found. by the method of peptide phage display and found that it is localized in the N-terminal part of HlyIICTD. The HlyIIC-20 interacted with a monomeric form of HlyII, thus suppressing maturation of the HlyII toxin. Protection efficiencies of various B. cereus strains against HlyII were different and depended on the epitope amino acid composition, as well as, insignificantly, on downstream amino acids. Substitution of L324P and P324L in the hemolysins ATCC14579T and B771, respectively, determined the role of leucine localized to the epitope in suppressing the hemolysis by the antibody. Pre-incubation of HlyIIC-20 with HlyII prevented the death of mice up to an equimolar ratio. A strategy of detecting and neutralizing the toxic activity of HlyII could provide a tool for monitoring and reducing B. cereus pathogenicity.
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Affiliation(s)
- Natalia Rudenko
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.Z.); (A.K.); (A.S.); (K.B.); (F.B.)
| | - Alexey Nagel
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.N.); (V.S.); (Z.A.-K.); (A.S.); (A.K.); (A.S.)
| | - Anna Zamyatina
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.Z.); (A.K.); (A.S.); (K.B.); (F.B.)
- Pushchino State Institute of Natural Sciences, 3 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia
| | - Anna Karatovskaya
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.Z.); (A.K.); (A.S.); (K.B.); (F.B.)
| | - Vadim Salyamov
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.N.); (V.S.); (Z.A.-K.); (A.S.); (A.K.); (A.S.)
| | - Zhanna Andreeva-Kovalevskaya
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.N.); (V.S.); (Z.A.-K.); (A.S.); (A.K.); (A.S.)
| | - Alexander Siunov
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.N.); (V.S.); (Z.A.-K.); (A.S.); (A.K.); (A.S.)
| | - Alexander Kolesnikov
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.N.); (V.S.); (Z.A.-K.); (A.S.); (A.K.); (A.S.)
| | - Anna Shepelyakovskaya
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.Z.); (A.K.); (A.S.); (K.B.); (F.B.)
| | - Khanafiy Boziev
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.Z.); (A.K.); (A.S.); (K.B.); (F.B.)
| | - Bogdan Melnik
- Protein Institute of the Russian Academy of Sciences, 4 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia;
| | - Fedor Brovko
- Pushchino Branch, Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 6 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.Z.); (A.K.); (A.S.); (K.B.); (F.B.)
| | - Alexander Solonin
- FSBIS FRC Pushchino Scientific Centre of Biological Research, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, 5 Prospekt Nauki, 142290 Pushchino, Moscow Region, Russia; (A.N.); (V.S.); (Z.A.-K.); (A.S.); (A.K.); (A.S.)
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9
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Rudenko NV, Karatovskaya AP, Zamyatina AV, Siunov AV, Andreeva-Kovalevskaya ZI, Nagel AS, Brovko FA, Solonin AS. C-Terminal Domain of Bacillus cereus Hemolysin II Is Able to Interact with Erythrocytes. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162020030188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bentin J, Balme S, Picaud F. Polynucleotide differentiation using hybrid solid-state nanopore functionalizing with α-hemolysin. SOFT MATTER 2020; 16:1002-1010. [PMID: 31853534 DOI: 10.1039/c9sm01833f] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report results from full atomistic molecular dynamics simulations on the properties of biomimetic nanopores. This latter result was obtained through the direct insertion of an α-hemolysin protein inside a hydrophobic solid-state nanopore. Upon translocation of different DNA strands, we demonstrate here that the theoretical system presents the same discrimination properties as the experimental one obtained previously. This opens an interesting way to promote the stability of a specific protein inside a solid nanopore to develop further biomimetic applications for DNA or protein sequencing.
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Affiliation(s)
- Jérémy Bentin
- Laboratoire de Nanomédecine, Imagerie et Thérapeutique, EA 4662, Université Bourgogne-Franche-Comté (UFR Sciences et Techniques), Centre Hospitalier Universitaire de Besançon, 16 route de Gray, 25030 Besançon, France.
| | - Sébastien Balme
- Institut Européen des Membranes, UMR5635 UM ENSCM CNRS, Place Eugène Bataillon, 34095 Montpellier cedex 5, France
| | - Fabien Picaud
- Laboratoire de Nanomédecine, Imagerie et Thérapeutique, EA 4662, Université Bourgogne-Franche-Comté (UFR Sciences et Techniques), Centre Hospitalier Universitaire de Besançon, 16 route de Gray, 25030 Besançon, France.
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11
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Lenhart B, Wei X, Zhang Z, Wang X, Wang Q, Liu C. Nanopore Fabrication and Application as Biosensors in Neurodegenerative Diseases. Crit Rev Biomed Eng 2020; 48:29-62. [PMID: 32749118 PMCID: PMC8020784 DOI: 10.1615/critrevbiomedeng.2020033151] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Since its conception as an applied biomedical technology nearly 30 years ago, nanopore is emerging as a promising, high-throughput, biomarker-targeted diagnostic tool for clinicians. The attraction of a nanopore-based detection system is its simple, inexpensive, robust, user-friendly, high-throughput blueprint with minimal sample preparation needed prior to analysis. The goal of clinical-based nanopore biosensing is to go from sample acquisition to a meaningful readout quickly. The most extensive work in nanopore applications has been targeted at DNA, RNA, and peptide identification. Although, biosensing of pathological biomarkers, which is covered in this review, is on the rise. This review is broken into two major sections: (i) the current state of existing biological, solid state, and hybrid nanopore systems and (ii) the applications of nanopore biosensors toward detecting neurodegenerative biomarkers.
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Affiliation(s)
- Brian Lenhart
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
| | - Xiaojun Wei
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
- Biomedical Engineering Program, University of South Carolina, Columbia, SC
| | - Zehui Zhang
- Biomedical Engineering Program, University of South Carolina, Columbia, SC
| | - Xiaoqin Wang
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
| | - Qian Wang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC
| | - Chang Liu
- Department of Chemical Engineering, University of South Carolina, Columbia, SC
- Biomedical Engineering Program, University of South Carolina, Columbia, SC
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12
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Cui Y, Märtlbauer E, Dietrich R, Luo H, Ding S, Zhu K. Multifaceted toxin profile, an approach toward a better understanding of probiotic Bacillus cereus. Crit Rev Toxicol 2019; 49:342-356. [PMID: 31116061 DOI: 10.1080/10408444.2019.1609410] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Strains of the Bacillus cereus group have been widely used as probiotics for human beings, food animals, plants, and environmental remediation. Paradoxically, B. cereus is responsible for both gastrointestinal and nongastrointestinal syndromes and represents an important opportunistic food-borne pathogen. Toxicity assessment is a fundamental issue to evaluate safety of probiotics. Here, we summarize the state of our current knowledge about the toxins of B. cereus sensu lato to be considered for safety assessment of probiotic candidates. Surfactin-like emetic toxin (cereulide) and various enterotoxins including nonhemolytic enterotoxin, hemolysin BL, and cytotoxin K are responsible for food poisoning outbreaks characterized by emesis and diarrhea. In addition, other factors, such as hemolysin II, Certhrax, immune inhibitor A1, and sphingomyelinase, contribute to toxicity and overall virulence of B. cereus.
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Affiliation(s)
- Yifang Cui
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University , Beijing , China.,State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University , Beijing , China
| | - Erwin Märtlbauer
- Department of Veterinary Sciences, Ludwig-Maximilians-University Munich , Oberschleißheim , Germany
| | - Richard Dietrich
- Department of Veterinary Sciences, Ludwig-Maximilians-University Munich , Oberschleißheim , Germany
| | - Hailing Luo
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University , Beijing , China
| | - Shuangyang Ding
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University , Beijing , China
| | - Kui Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Veterinary Medicine, China Agricultural University , Beijing , China.,National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University , Beijing , China
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13
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Koo S, Cheley S, Bayley H. Redirecting Pore Assembly of Staphylococcal α-Hemolysin by Protein Engineering. ACS CENTRAL SCIENCE 2019; 5:629-639. [PMID: 31041382 PMCID: PMC6487460 DOI: 10.1021/acscentsci.8b00910] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Indexed: 05/03/2023]
Abstract
α-Hemolysin (αHL), a β-barrel pore-forming toxin (βPFT), is secreted as a water-soluble monomer by Staphylococcus aureus. Upon binding to receptors on target cell membranes, αHL assembles to form heptameric membrane-spanning pores. We have previously engineered αHL to create a protease-activatable toxin that is activated by site-specific proteolysis including by tumor proteases. In this study, we redesigned αHL so that it requires 2-fold activation on target cells through (i) binding to specific receptors, and (ii) extracellular proteolytic cleavage. To assess our strategy, we constructed a fusion protein of αHL with galectin-1 (αHLG1, αHL-Galectin-1 chimera). αHLG1 was cytolytic toward cells that lack a receptor for wild-type αHL. We then constructed protease-activatable mutants of αHLG1 (PAMαHLG1s). PAMαHLG1s were activated by matrix metalloproteinase 2 (MMP-2) and had approximately 50-fold higher cytolytic activity toward MMP-2 overexpressing cells (HT-1080 cells) than toward non-overexpressing cells (HL-60 cells). Our approach provides a novel strategy for tailoring pore-forming toxins for therapeutic applications.
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Affiliation(s)
- Sunwoo Koo
- Department
of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, 8447 Riverside Parkway, Bryan, Texas 77807, United States
- E-mail: . Phone: 1-979-436-0381
| | - Stephen Cheley
- Department
of Pharmacology, Alberta Diabetes Institute, University of Alberta, Edmonton, T6G 2E1 Alberta, Canada
| | - Hagan Bayley
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield
Road, Oxford, OX1 3TA England, United Kingdom
- E-mail: . Phone: +44 1865 285101
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14
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Qing Y, Ionescu SA, Pulcu GS, Bayley H. Directional control of a processive molecular hopper. Science 2018; 361:908-912. [DOI: 10.1126/science.aat3872] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Accepted: 06/21/2018] [Indexed: 01/08/2023]
Abstract
Intrigued by the potential of nanoscale machines, scientists have long attempted to control molecular motion. We monitored the individual 0.7-nanometer steps of a single molecular hopper as it moved in an electric field along a track in a nanopore controlled by a chemical ratchet. The hopper demonstrated characteristics desired in a moving molecule: defined start and end points, processivity, no chemical fuel requirement, directional motion, and external control. The hopper was readily functionalized to carry cargos. For example, a DNA molecule could be ratcheted along the track in either direction, a prerequisite for nanopore sequencing.
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15
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Osman KM, Kappell AD, Orabi A, Al-Maary KS, Mubarak AS, Dawoud TM, Hemeg HA, Moussa IMI, Hessain AM, Yousef HMY, Hristova KR. Poultry and beef meat as potential seedbeds for antimicrobial resistant enterotoxigenic Bacillus species: a materializing epidemiological and potential severe health hazard. Sci Rep 2018; 8:11600. [PMID: 30072706 PMCID: PMC6072766 DOI: 10.1038/s41598-018-29932-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 07/18/2018] [Indexed: 12/17/2022] Open
Abstract
Although Bacillus cereus is of particular concern in food safety and public health, the role of other Bacillus species was overlooked. Therefore, we investigated the presence of eight enterotoxigenic genes, a hemolytic gene and phenotypic antibiotic resistance profiles of Bacillus species in retail meat samples. From 255 samples, 124 Bacillus isolates were recovered, 27 belonged to B. cereus and 97 were non-B. cereus species. Interestingly, the non-B. cereus isolates carried the virulence genes and exhibited phenotypic virulence characteristics as the B. cereus. However, correlation matrix analysis revealed the B. cereus group positively correlates with the presence of the genes hblA, hblC, and plc, and the detection of hemolysis (p < 0.05), while the other Bacillus sp. groups are negatively correlated. Tests for antimicrobial resistance against ten antibiotics revealed extensive drug and multi-drug resistant isolates. Statistical analyses didn't support a correlation of antibiotic resistance to tested virulence factors suggesting independence of these phenotypic markers and virulence genes. Of special interest was the isolation of Paenibacillus alvei and Geobacillus stearothermophilus from the imported meat samples being the first recorded. The isolation of non-B. cereus species carrying enterotoxigenic genes in meat within Egypt, suggests their impact on food safety and public health and should therefore not be minimised, posing an area that requires further research.
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Affiliation(s)
- Kamelia M Osman
- Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Anthony D Kappell
- Department of Civil, Construction, and Environmental Engineering, Marquette University, Milwaukee, WI, USA
| | - Ahmed Orabi
- Department of Microbiology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Khalid S Al-Maary
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Ayman S Mubarak
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Turki M Dawoud
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Hassan A Hemeg
- Department of Clinical Laboratory sciences, college of Applied Medical sciences, Taibah University, Taibah, Saudi Arabia
| | - Ihab M I Moussa
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Ashgan M Hessain
- Department of Health Science, College of Applied Studies and Community Service, King Saud University, Riyadh, Saudi Arabia
| | - Hend M Y Yousef
- Central Administration of Preventive Medicine, General Organization for Veterinary Service, Giza, Egypt.
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16
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Characterization of Enterotoxigenic Bacillus cereus sensu lato and Staphylococcus aureus Isolates and Associated Enterotoxin Production Dynamics in Milk or Meat-Based Broth. Toxins (Basel) 2017; 9:toxins9070225. [PMID: 28714887 PMCID: PMC5535172 DOI: 10.3390/toxins9070225] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/13/2017] [Accepted: 07/13/2017] [Indexed: 02/05/2023] Open
Abstract
Bacillus cereus sensu lato species, as well as Staphylococcus aureus, are important pathogenic bacteria which can cause foodborne illness through the production of enterotoxins. This study characterised enterotoxin genes of these species and examined growth and enterotoxin production dynamics of isolates when grown in milk or meat-based broth. All B. cereus s. l. isolates harboured nheA, hblA and entFM toxin genes, with lower prevalence of bceT and hlyII. When grown at 16 °C, toxin production by individual B. cereus s. l. isolates varied depending on the food matrix; toxin was detected at cell densities below 5 log10(CFU/mL). At 16 °C no staphylococcal enterotoxin C (SEC) production was detected by S. aureus isolates, although low levels of SED production was noted. At 30 °C all S. aureus isolates produced detectable enterotoxin in the simulated meat matrix, whereas SEC production was significantly reduced in milk. Relative to B. cereus s. l. toxin production, S. aureus typically required reaching higher cell numbers to produce detectable levels of enterotoxin. Phylogenetic analysis of the sec and sel genes suggested population evolution which correlated with animal host adaptation, with subgroups of bovine isolates or caprine/ovine isolates noted, which were distinct from human isolates. Taken together, this study highlights the marked differences in the production of enterotoxins both associated with different growth matrices themselves, but also in the behaviour of individual strains when exposed to different food matrices.
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17
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Kaplan AR, Kaus K, De S, Olson R, Alexandrescu AT. NMR structure of the Bacillus cereus hemolysin II C-terminal domain reveals a novel fold. Sci Rep 2017; 7:3277. [PMID: 28607368 PMCID: PMC5468326 DOI: 10.1038/s41598-017-02917-4] [Citation(s) in RCA: 9] [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: 02/02/2017] [Accepted: 04/20/2017] [Indexed: 11/09/2022] Open
Abstract
In addition to multiple virulence factors, Bacillus cereus a pathogen that causes food poisoning and life-threatening wound infections, secretes the pore-forming toxin hemolysin II (HlyII). The HlyII toxin has a unique 94 amino acid C-terminal domain (HlyIIC). HlyIIC exhibits splitting of NMR resonances due to cis/trans isomerization of a single proline near the C-terminus. To overcome heterogeneity, we solved the structure of P405M-HlyIIC, a mutant that exclusively stabilizes the trans state. The NMR structure of HlyIIC reveals a novel fold, consisting of two subdomains αA-β1-β2 and β3-β4-αB-β5, that come together in a barrel-like structure. The barrel core is fastened by three layers of hydrophobic residues. The barrel end opposite the HlyIIC-core has a positively charged surface, that by binding negatively charged moieties on cellular membranes, may play a role in target-cell surface recognition or stabilization of the heptameric pore complex. In the WT domain, dynamic flexibility occurs at the N-terminus and the first α-helix that connects the HlyIIC domain to the HlyII-core structure. In the destabilizing P405M mutant, increased flexibility is evident throughout the first subdomain, suggesting that the HlyIIC structure may have arisen through gene fusion.
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Affiliation(s)
- Anne R Kaplan
- Department of Molecular and Cell Biology, University of Connecticut, 91 N. Eagleville Rd, Storrs, CT, 06269-3125, USA
| | - Katherine Kaus
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, 224 Hall-Atwater, 52 Lawn Ave., Middletown, CT, 06459-0175, USA
| | - Swastik De
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, 224 Hall-Atwater, 52 Lawn Ave., Middletown, CT, 06459-0175, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT, 06520-8114, USA
| | - Rich Olson
- Department of Molecular Biology and Biochemistry, Molecular Biophysics Program, Wesleyan University, 224 Hall-Atwater, 52 Lawn Ave., Middletown, CT, 06459-0175, USA.
| | - Andrei T Alexandrescu
- Department of Molecular and Cell Biology, University of Connecticut, 91 N. Eagleville Rd, Storrs, CT, 06269-3125, USA.
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18
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Merlos A, Rodríguez P, Bárcena-Uribarri I, Winterhalter M, Benz R, Vinuesa T, Moya JA, Viñas M. Toxins Secreted by Bacillus Isolated from Lung Adenocarcinomas Favor the Penetration of Toxic Substances. Front Microbiol 2015; 6:1301. [PMID: 26635767 PMCID: PMC4655230 DOI: 10.3389/fmicb.2015.01301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/06/2015] [Indexed: 01/17/2023] Open
Abstract
The aim was to explore the eventual role of bacteria in the induction of lung cancer by smoking habits. Viable bacteria closely related to the genus Bacillus were detected at high frequencies in lung-cancer biopsies. Similar, if not identical, microbes were isolated from cigarettes and in smog. Bacteria present in cigarettes could be transferred to a physiological solution via a "smoker" device that mimicked their potential transfer during smoking those bacteria produce exotoxins able to open transmembrane pores. These channels can be used as a way to penetrate cells of benzopyrenes and other toxic substances present in tobacco products. We hypothesize that Bacillaceae present in tobacco play a key role in the development of lung cancer.
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Affiliation(s)
- Alexandra Merlos
- Molecular Microbiology and Antibiotics, Department of Pathology and Experimental Therapeutics, Medical School, University of Barcelona Barcelona, Spain
| | - Pau Rodríguez
- Department of Thoracic Surgery, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL-HUB Barcelona, Spain
| | | | | | | | - Teresa Vinuesa
- Molecular Microbiology and Antibiotics, Department of Pathology and Experimental Therapeutics, Medical School, University of Barcelona Barcelona, Spain
| | - Juan A Moya
- Department of Thoracic Surgery, Hospital Universitari de Bellvitge, University of Barcelona-IDIBELL-HUB Barcelona, Spain
| | - Miguel Viñas
- Molecular Microbiology and Antibiotics, Department of Pathology and Experimental Therapeutics, Medical School, University of Barcelona Barcelona, Spain ; Cooperativa de Ensino Superior Politécnico e Universitário, IINFACTS Gandra, Portugal
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19
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Kholodkov OA, Budarina ZI, Andreeva-Kovalevskaya ZI, Siunov AV, Solonin AS. Effect of Bacillus cereus hemolysin II on hepatocyte cells. APPL BIOCHEM MICRO+ 2015. [DOI: 10.1134/s000368381502009x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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20
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Tewari A, Singh SP, Singh R. Incidence and enterotoxigenic profile of Bacillus cereus in meat and meat products of Uttarakhand, India. JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2015; 52:1796-801. [PMID: 25745259 PMCID: PMC4348265 DOI: 10.1007/s13197-013-1162-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 08/20/2013] [Accepted: 08/25/2013] [Indexed: 10/26/2022]
Abstract
The present investigation was undertaken to study the incidence and enterotoxigenicity of Bacillus cereus in raw meat and meat products. B. cereus was isolated from 29 (30.9 %) of the 94 samples analyzed. Recorded incidences of B. cereus from raw meat and meat products samples were 27.8 and 35 %, respectively. A high level of organism was found in cooked-meat (35 %) than raw meat samples (27.78 %) from 40 cooked-meat products and 54 raw meat samples analyzed. Screening of isolates by multiplex polymerase chain reaction revealed the overall distribution of various enterotoxin genes hblDAC complex, nheABC complex, cytK and entFM as 55.2, 89.7, 41.4 and 93 %, respectively. The level of contamination with B. cereus was moderately higher in some samples but did not exceed the level which is sufficient to induce food poisoning. A relatively higher incidence of B. cereus in meat products, with the majority of isolates harboring all the enterotoxin genes can pose a potential public health threat.
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Affiliation(s)
- Anita Tewari
- />School of Public Health & Zoonoses, Guru Angad Dev Veterinary & Animal Sciences University, Ludhiana, Punjab 141004 India
| | - S. P. Singh
- />Department of Veterinary Public Health & Epidemiology, Govind Ballabh Pant Agriculture and Technology, Pantnagar, Uttrakhand India
| | - Rashmi Singh
- />Pt. Deen Dayal Upadhaya Pashu Chikitsa Vigyan Vishwa Vidhyalaya, Mathura, Uttar Pradesh India
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21
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Perlińska A, Grynberg M. Bacillus anthracis pXO1 plasmid encodes a putative membrane-bound bacteriocin. PeerJ 2014; 2:e679. [PMID: 25426338 PMCID: PMC4243335 DOI: 10.7717/peerj.679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 11/06/2014] [Indexed: 11/20/2022] Open
Abstract
Evolutionary advantages over cousin cells in bacterial pathogens may decide about the success of a specific cell in its environment. Bacteria use a plethora of methods to defend against other cells and many devices to attack their opponents when competing for resources. Bacteriocins are antibacterial proteins that are used to eliminate competition. We report the discovery of a putative membrane-bound bacteriocin encoded by the Bacillus anthracis pathogenic pXO1 plasmid. We analyze the genomic structure of the bacteriocin operon. The proposed mechanisms of action predestine this operon as a potent competitive advantage over cohabitants of the same niche.
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Affiliation(s)
- Agata Perlińska
- Centre of New Technologies, University of Warsaw , Banacha, Warsaw , Poland
| | - Marcin Grynberg
- Institute of Biochemistry and Biophysics PAS , Pawińskiego, Warsaw , Poland
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22
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Kaplan AR, Maciejewski MW, Olson R, Alexandrescu AT. NMR assignments for the cis and trans forms of the hemolysin II C-terminal domain. BIOMOLECULAR NMR ASSIGNMENTS 2014; 8:419-423. [PMID: 24234348 DOI: 10.1007/s12104-013-9530-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 10/29/2013] [Indexed: 06/02/2023]
Abstract
Pathogenic bacteria secrete pore-forming toxins (PFTs) to selectively defend against immune cells and to break through cellular barriers in the host. Understanding how PFTs attack cell membranes is not only essential for therapeutic intervention but for designing agents to deliver drugs to specific human cell subtypes, for example in anti-cancer or anti-viral therapies. Many toxins contain accessory domains that help recognize specific molecular epitopes on the membranes of target cells, including proteins, carbohydrates, and lipids. Here we report NMR assignments for the 94-residue 10 kDa C-terminal accessory domain of Bacillus cereus hemolysin II, HlyIIC, that has no known structural or functional homologues. The HlyIIC domain exists in a dynamic equilibrium due to cis/trans isomerization of its Gly86-Pro87 peptide bond. The cis and trans forms are about equally populated and are in slow exchange on the NMR timescale, giving rise to separate signals for approximately half of the residues in the domain. Assignments for the cis and trans forms were achieved with the aid of a P87M mutant that stabilizes the trans form, and separate sequential walks for the two forms in 3D NMR spectra of the wild-type HlyIIC. Based on backbone chemical shifts, the domain has a α1-α2-β1-β2-β3-β4-α3-β5 order of secondary structure elements. The last strand in the trans form and in the P87M mutant is shortened near Pro87 compared to the cis form. Both cis/trans isomerization and the P87M mutation cause large chemical shift changes throughout HlyIIC, suggesting that the proline is important in stabilizing the structure of the domain. The NMR assignments pave the way for solving the structures of the multiple conformational forms of HlyIIC and establishing their mechanism of interconversion.
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23
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Kacprzyk-Stokowiec A, Kulma M, Traczyk G, Kwiatkowska K, Sobota A, Dadlez M. Crucial role of perfringolysin O D1 domain in orchestrating structural transitions leading to membrane-perforating pores: a hydrogen-deuterium exchange study. J Biol Chem 2014; 289:28738-52. [PMID: 25164812 DOI: 10.1074/jbc.m114.577981] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Perfringolysin O (PFO) is a toxic protein that binds to cholesterol-containing membranes, oligomerizes, and forms a β-barrel transmembrane pore, leading to cell lysis. Previous studies have uncovered the sequence of events in this multistage structural transition to a considerable detail, but the underlying molecular mechanisms are not yet fully understood. By measuring hydrogen-deuterium exchange patterns of peptide bond amide protons monitored by mass spectrometry (MS), we have mapped structural changes in PFO and its variant bearing a point mutation during incorporation to the lipid environment. We have defined all regions that undergo structural changes caused by the interaction with the lipid environment both in wild-type PFO, thus providing new experimental constraints for molecular modeling of the pore formation process, and in a point mutant, W165T, for which the pore formation process is known to be inefficient. We have demonstrated that point mutation W165T causes destabilization of protein solution structure, strongest for domain D1, which interrupts the pathway of structural transitions in other domains necessary for proper oligomerization in the membrane. In PFO, the strongest changes accompanying binding to the membrane focus in D1; the C-terminal part of D4; and strands β1, β4, and β5 of D3. These changes were much weaker for PFO(W165T) lipo where substantial stabilization was observed only in D4 domain. In this study, the application of hydrogen-deuterium exchange analysis monitored by MS provided new insight into conformational changes of PFO associated with the membrane binding, oligomerization, and lytic pore formation.
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Affiliation(s)
- Aleksandra Kacprzyk-Stokowiec
- From the Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego St., 02-106 Warsaw, Poland
| | - Magdalena Kulma
- From the Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego St., 02-106 Warsaw, Poland
| | - Gabriela Traczyk
- Department of Cell Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland, and
| | - Katarzyna Kwiatkowska
- Department of Cell Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland, and
| | - Andrzej Sobota
- Department of Cell Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland, and
| | - Michał Dadlez
- From the Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego St., 02-106 Warsaw, Poland, Department of Biology, Institute of Genetics and Biotechnology, Warsaw University, 1 Miecznikowa Street, 02-185 Warsaw, Poland
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24
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Olchowik-Grabarek E, Swiecicka I, Andreeva-Kovaleskaya Z, Solonin A, Bonarska-Kujawa D, Kleszczyńska H, Mavlyanov S, Zamaraeva M. Role of Structural Changes Induced in Biological Membranes by Hydrolysable Tannins from Sumac Leaves (Rhus typhina L.) in their Antihemolytic and Antibacterial Effects. J Membr Biol 2014; 247:533-40. [DOI: 10.1007/s00232-014-9664-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/09/2014] [Indexed: 01/03/2023]
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25
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Fairhead M, Krndija D, Lowe ED, Howarth M. Plug-and-play pairing via defined divalent streptavidins. J Mol Biol 2013; 426:199-214. [PMID: 24056174 PMCID: PMC4047826 DOI: 10.1016/j.jmb.2013.09.016] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/07/2013] [Accepted: 09/12/2013] [Indexed: 11/29/2022]
Abstract
Streptavidin is one of the most important hubs for molecular biology, either multimerizing biomolecules, bridging one molecule to another, or anchoring to a biotinylated surface/nanoparticle. Streptavidin has the advantage of rapid ultra-stable binding to biotin. However, the ability of streptavidin to bind four biotinylated molecules in a heterogeneous manner is often limiting. Here, we present an efficient approach to isolate streptavidin tetramers with two biotin-binding sites in a precise arrangement, cis or trans. We genetically modified specific subunits with negatively charged tags, refolded a mixture of monomers, and used ion-exchange chromatography to resolve tetramers according to the number and orientation of tags. We solved the crystal structures of cis-divalent streptavidin to 1.4 Å resolution and trans-divalent streptavidin to 1.6 Å resolution, validating the isolation strategy and explaining the behavior of the Dead streptavidin variant. cis- and trans-divalent streptavidins retained tetravalent streptavidin's high thermostability and low off-rate. These defined divalent streptavidins enabled us to uncover how streptavidin binding depends on the nature of the biotin ligand. Biotinylated DNA showed strong negative cooperativity of binding to cis-divalent but not trans-divalent streptavidin. A small biotinylated protein bound readily to cis and trans binding sites. We also solved the structure of trans-divalent streptavidin bound to biotin-4-fluorescein, showing how one ligand obstructs binding to an adjacent biotin-binding site. Using a hexaglutamate tag proved a more powerful way to isolate monovalent streptavidin, for ultra-stable labeling without undesired clustering. These forms of streptavidin allow this key hub to be used with a new level of precision, for homogeneous molecular assembly. Streptavidin is a widely used nanohub: often, tetravalency makes assembly imprecise. We isolated divalent streptavidins with biotin-binding sites in cis or in trans. cis- and trans-divalent streptavidins retain exceptional biotin binding and thermostability. Binding large biotinylated ligands to adjacent binding sites is greatly disfavored. cis- and trans-divalent streptavidins represent a simple way to bridge biomolecules precisely.
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Affiliation(s)
- Michael Fairhead
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Denis Krndija
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Ed D Lowe
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark Howarth
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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Dyrka W, Bartuzel MM, Kotulska M. Optimization of 3D Poisson-Nernst-Planck model for fast evaluation of diverse protein channels. Proteins 2013; 81:1802-22. [PMID: 23720356 DOI: 10.1002/prot.24326] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 05/02/2013] [Accepted: 05/09/2013] [Indexed: 12/12/2022]
Abstract
We show the accuracy and applicability of our fast algorithmic implementation of a three-dimensional Poisson-Nernst-Planck (3D-PNP) flow model for characterizing different protein channels. Due to its high computational efficiency, our model can predict the full current-voltage characteristics of a channel within minutes, based on the experimental 3D structure of the channel or its computational model structure. Compared with other methods, such as Brownian dynamics, which currently needs a few weeks of the computational time, or even much more demanding molecular dynamics modeling, 3D-PNP is the only available method for a function-based evaluation of very numerous tentative structural channel models. Flow model tests of our algorithm and its optimal parametrization are provided for five native channels whose experimental structures are available in the protein data bank (PDB) in an open conductive state, and whose experimental current-voltage characteristics have been published. The channels represent very different geometric and structural properties, which makes it the widest test to date of the accuracy of 3D-PNP on real channels. We test whether the channel conductance, rectification, and charge selectivity obtained from the flow model, could be sufficiently sensitive to single-point mutations, related to unsignificant changes in the channel structure. Our results show that the classical 3D-PNP model, under proper parametrization, is able to achieve a qualitative agreement with experimental data for a majority of the tested characteristics and channels, including channels with narrow and irregular conductivity pores. We propose that although the standard PNP model cannot provide insight into complex physical phenomena due to its intrinsic limitations, its semiquantitative agreement is achievable for rectification and selectivity at a level sufficient for the bioinformatical purpose of selecting the best structural models with a great advantage of a very short computational time.
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Affiliation(s)
- Witold Dyrka
- Group of Bioinformatics and Biophysics of Nanopores, Institute of Biomedical Engineering and Instrumentation, Wroclaw University of Technology, Wroclaw, Poland
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The pore-forming haemolysins of bacillus cereus: a review. Toxins (Basel) 2013; 5:1119-39. [PMID: 23748204 PMCID: PMC3717773 DOI: 10.3390/toxins5061119] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/22/2013] [Accepted: 05/24/2013] [Indexed: 12/05/2022] Open
Abstract
The Bacillus cereus sensu lato group contains diverse Gram-positive spore-forming bacteria that can cause gastrointestinal diseases and severe eye infections in humans. They have also been incriminated in a multitude of other severe, and frequently fatal, clinical infections, such as osteomyelitis, septicaemia, pneumonia, liver abscess and meningitis, particularly in immuno-compromised patients and preterm neonates. The pathogenic properties of this organism are mediated by the synergistic effects of a number of virulence products that promote intestinal cell destruction and/or resistance to the host immune system. This review focuses on the pore-forming haemolysins produced by B. cereus: haemolysin I (cereolysin O), haemolysin II, haemolysin III and haemolysin IV (CytK). Haemolysin I belongs to the cholesterol-dependent cytolysin (CDC) family whose best known members are listeriolysin O and perfringolysin O, produced by L. monocytogenes and C. perfringens respectively. HlyII and CytK are oligomeric ß-barrel pore-forming toxins related to the α-toxin of S. aureus or the ß-toxin of C. perfringens. The structure of haemolysin III, the least characterized haemolytic toxin from the B. cereus, group has not yet been determined.
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Iron regulates Bacillus thuringiensis haemolysin hlyII gene expression during insect infection. J Invertebr Pathol 2013; 113:205-8. [PMID: 23598183 DOI: 10.1016/j.jip.2013.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 03/29/2013] [Accepted: 04/04/2013] [Indexed: 11/22/2022]
Abstract
Bacillus thuringiensis (Bt) is a spore-forming entomopathogen broadly used in agriculture crop. The haemolysin HlyII is an important Bt virulence factor responsible for insect death. In this work, we focused on the regulation of the hlyII gene throughout the bacterial growth in vitro and in vivo during insect infection. We show that hlyII regulation depends on the global regulator Fur. This regulation occurs independently of HlyIIR, the other known regulator of hlyII gene expression. Moreover, we show that hlyII is highly expressed when iron is depleted in vivo. As HlyII induces haemocyte and macrophage death, which are involved in the sequestration of iron upon infection, HlyII may induce host cell death to allow bacteria to gain access to iron.
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29
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Glucose 6P binds and activates HlyIIR to repress Bacillus cereus haemolysin hlyII gene expression. PLoS One 2013; 8:e55085. [PMID: 23405113 PMCID: PMC3566180 DOI: 10.1371/journal.pone.0055085] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 12/17/2012] [Indexed: 11/19/2022] Open
Abstract
Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation despite the recruitment of phagocytic cells. We have previously shown that B. cereus Haemolysin II (HlyII) induces macrophage cell death by apoptosis. In this work, we investigated the regulation of the hlyII gene. We show that HlyIIR, the negative regulator of hlyII expression in B. cereus, is especially active during the early bacterial growth phase. We demonstrate that glucose 6P directly binds to HlyIIR and enhances its activity at a post-transcriptional level. Glucose 6P activates HlyIIR, increasing its capacity to bind to its DNA-box located upstream of the hlyII gene, inhibiting its expression. Thus, hlyII expression is modulated by the availability of glucose. As HlyII induces haemocyte and macrophage death, two cell types that play a role in the sequestration of nutrients upon infection, HlyII may induce host cell death to allow the bacteria to gain access to carbon sources that are essential components for bacterial growth.
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30
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Tran SL, Puhar A, Ngo-Camus M, Ramarao N. Trypan blue dye enters viable cells incubated with the pore-forming toxin HlyII of Bacillus cereus. PLoS One 2011; 6:e22876. [PMID: 21909398 PMCID: PMC3167804 DOI: 10.1371/journal.pone.0022876] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 07/06/2011] [Indexed: 12/29/2022] Open
Abstract
Trypan blue is a dye that has been widely used for selective staining of dead tissues or cells. Here, we show that the pore-forming toxin HlyII of Bacillus cereus allows trypan blue staining of macrophage cells, despite the cells remaining viable and metabolically active. These findings suggest that the dye enters viable cells through the pores. To our knowledge, this is the first demonstration that trypan blue may enter viable cells. Consequently, the use of trypan blue staining as a marker of vital status should be interpreted with caution. The blue coloration does not necessarily indicate cell lysis, but may rather indicate pore formation in the cell membranes and more generally increased membrane permeability.
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Affiliation(s)
- Seav-Ly Tran
- INRA, Unité MICALIS, UMR 1319, Guyancourt, France
| | - Andrea Puhar
- Unité PMM, INSERM U786, Institut Pasteur, Paris, France
| | | | - Nalini Ramarao
- INRA, Unité MICALIS, UMR 1319, Guyancourt, France
- * E-mail:
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31
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Hammerstein AF, Jayasinghe L, Bayley H. Subunit dimers of alpha-hemolysin expand the engineering toolbox for protein nanopores. J Biol Chem 2011; 286:14324-34. [PMID: 21324910 PMCID: PMC3077633 DOI: 10.1074/jbc.m111.218164] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 02/10/2011] [Indexed: 12/27/2022] Open
Abstract
Staphylococcal α-hemolysin (αHL) forms a heptameric pore that features a 14-stranded transmembrane β-barrel. We attempted to force the αHL pore to adopt novel stoichiometries by oligomerizing subunit dimers generated by in vitro transcription and translation of a tandem gene. However, in vitro transcription and translation also produced truncated proteins, monomers, that were preferentially incorporated into oligomers. These oligomers were shown to be functional heptamers by single-channel recording and had a similar mobility to wild-type heptamers in SDS-polyacrylamide gels. Purified full-length subunit dimers were then prepared by using His-tagged protein. Again, single-channel recording showed that oligomers made from these dimers are functional heptamers, implying that one or more subunits are excluded from the central pore. Therefore, the αHL pore resists all structures except those that possess seven subunits immediately surrounding the central axis. Although we were not able to change the stoichiometry of the central pore of αHL by the concatenation of subunits, we extended our findings to prepare pores containing one subunit dimer and five monomers and purified them by SDS-PAGE. Two half-chelating ligands were then installed at adjacent sites, one on each subunit of the dimer. Single-channel recording showed that pores formed from this construct formed complexes with divalent metal ions in a similar fashion to pores containing two half-chelating ligands on the same subunit, confirming that the oligomers had assembled with seven subunits around the central lumen. The ability to incorporate subunit dimers into αHL pores increases the range of structures that can be obtained from engineered protein nanopores.
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Affiliation(s)
- Anne F. Hammerstein
- From the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Lakmal Jayasinghe
- From the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Hagan Bayley
- From the Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
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32
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Tran SL, Guillemet E, Ngo-Camus M, Clybouw C, Puhar A, Moris A, Gohar M, Lereclus D, Ramarao N. Haemolysin II is a Bacillus cereus virulence factor that induces apoptosis of macrophages. Cell Microbiol 2011; 13:92-108. [PMID: 20731668 DOI: 10.1111/j.1462-5822.2010.01522.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation despite the recruitment of phagocytic cells. The precise mechanisms and the bacterial factors allowing B. cereus to circumvent host immune responses remain to be elucidated. We have previously shown that B. cereus induces macrophage cell death by an unknown mechanism. Here we identified the toxic component from the B. cereus supernatant. We report that Haemolysin II (HlyII) provokes macrophage cell death by apoptosis through its pore-forming activity. The HlyII-induced apoptotic pathway is caspase 3 and 8 dependent, thus most likely mediated by the death receptor pathway. Using insects and mice as in vivo models, we show that deletion of hlyII strongly reduces virulence. In addition, we show that after infection of Bombyx mori larvae, the immune cells are apoptotic, demonstrating that HlyII induces apoptosis of phagocytic cells in vivo. Altogether, our results clearly unravel HlyII as a novel virulence protein that induces apoptosis in phagocytic cells in vitro and in vivo.
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Affiliation(s)
- Seav-Ly Tran
- INRA, Unité MICALIS, UMR 1319, équipe GME, La Minière, 78285 Guyancourt, France
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33
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Tran SL, Guillemet E, Ngo-Camus M, Clybouw C, Puhar A, Moris A, Gohar M, Lereclus D, Ramarao N. Haemolysin II is a Bacillus cereus virulence factor that induces apoptosis of macrophages. Cell Microbiol 2010. [DOI: 10.1111/j.1462-5822.2010.001522.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Haug TM, Sand SL, Sand O, Phung D, Granum PE, Hardy SP. Formation of very large conductance channels by Bacillus cereus Nhe in Vero and GH(4) cells identifies NheA + B as the inherent pore-forming structure. J Membr Biol 2010; 237:1-11. [PMID: 20821199 PMCID: PMC2947714 DOI: 10.1007/s00232-010-9298-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 08/13/2010] [Indexed: 11/30/2022]
Abstract
The nonhemolytic enterotoxin (Nhe) produced by Bacillus cereus is a pore-forming toxin consisting of three components, NheA, -B and -C. We have studied effects of Nhe on primate epithelial cells (Vero) and rodent pituitary cells (GH4) by measuring release of lactate dehydrogenase (LDH), K+ efflux and the cytosolic Ca2+ concentration ([Ca2+]i). Plasma membrane channel events were monitored by patch-clamp recordings. Using strains of B. cereus lacking either NheA or -C, we examined the functional role of the various components. In both cell types, NheA + B + C induced release of LDH and K+ as well as Ca2+ influx. A specific monoclonal antibody against NheB abolished LDH release and elevation of [Ca2+]i. Exposure to NheA + B caused a similar K+ efflux and elevation of [Ca2+]i as NheA + B + C in GH4 cells, whereas in Vero cells the rate of K+ efflux was reduced by 50% and [Ca2+]i was unaffected. NheB + C had no effect on either cell type. Exposure to NheA + B + C induced large-conductance steps in both cell types, and similar channel insertions were observed in GH4 cells exposed to NheA + B. In Vero cells, NheA + B induced channels of much smaller conductance. NheB + C failed to insert membrane channels. The conductance of the large channels in GH4 cells was about 10 nS. This is the largest channel conductance reported in cell membranes under quasi-physiological conditions. In conclusion, NheA and NheB are necessary and sufficient for formation of large-conductance channels in GH4 cells, whereas in Vero cells such large-conductance channels are in addition dependent on NheC.
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Affiliation(s)
- Trude M Haug
- Department of Molecular Biosciences, University of Oslo, Post Box 1041, 0316 Oslo, Norway.
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35
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Tan Q, Shim JW, Gu LQ. Separation of heteromeric potassium channel Kcv towards probing subunit composition-regulated ion permeation and gating. FEBS Lett 2010; 584:1602-8. [PMID: 20303961 DOI: 10.1016/j.febslet.2010.03.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 03/12/2010] [Accepted: 03/15/2010] [Indexed: 11/19/2022]
Abstract
The chlorella virus-encoded Kcv can form a homo-tetrameric potassium channel in lipid membranes. This miniature peptide can be synthesized in vitro, and the tetramer purified from the SDS-polyacrylamide gel retains the K(+) channel functionality. Combining this capability with the mass-tagging method, we propose a simple, straightforward approach that can generically manipulate individual subunits in the tetramer, thereby enabling the detection of contribution from individual subunits to the channel functions. Using this approach, we showed that the structural change in the selectivity filter from only one subunit is sufficient to cause permanent channel inactivation ("all-or-none" mechanism), whereas the mutation near the extracellular entrance additively modifies the ion permeation with the number of mutant subunits in the tetramer ("additive" mechanism).
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Affiliation(s)
- Qiulin Tan
- Department of Biological Engineering, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
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36
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InhA1, NprA, and HlyII as candidates for markers to differentiate pathogenic from nonpathogenic Bacillus cereus strains. J Clin Microbiol 2010; 48:1358-65. [PMID: 20129969 DOI: 10.1128/jcm.02123-09] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacillus cereus is found in food, soil, and plants, and the ability to cause food-borne diseases and opportunistic infection presumably varies among strains. Therefore, measuring harmful toxin production, in addition to the detection of the bacterium itself, may be key for food and hospital safety purposes. All previous studies have focused on the main known virulence factors, cereulide, Hbl, Nhe, and CytK. We examined whether other virulence factors may be specific to pathogenic strains. InhA1, NprA, and HlyII have been described as possibly contributing to B. cereus pathogenicity. We report the prevalence and expression profiles of these three new virulence factor genes among 57 B. cereus strains isolated from various sources, including isolates associated with gastrointestinal and nongastrointestinal diseases. Using PCR, quantitative reverse transcriptase PCR, and virulence in vivo assays, we unraveled these factors as potential markers to differentiate pathogenic from nonpathogenic strains. We show that the hlyII gene is carried only by strains with a pathogenic potential and that the expression levels of inhA1 and nprA are higher in the pathogenic than in the nonpathogenic group of strains studied. These data deliver useful information about the pathogenicity of various B. cereus strains.
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37
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Maglia G, Heron AJ, Stoddart D, Japrung D, Bayley H. Analysis of single nucleic acid molecules with protein nanopores. Methods Enzymol 2010; 475:591-623. [PMID: 20627172 DOI: 10.1016/s0076-6879(10)75022-9] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
We describe the methods used in our laboratory for the analysis of single nucleic acid molecules with protein nanopores. The technical section is preceded by a review of the variety of experiments that can be done with protein nanopores. The end goal of much of this work is single-molecule DNA sequencing, although sequencing is not discussed explicitly here. The technical section covers the equipment required for nucleic acid analysis, the preparation and storage of the necessary materials, and aspects of signal processing and data analysis.
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Affiliation(s)
- Giovanni Maglia
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
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38
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The aromatic ring of phenylalanine 334 is essential for oligomerization of Vibrio vulnificus hemolysin. J Bacteriol 2009; 192:568-74. [PMID: 19897654 DOI: 10.1128/jb.01049-09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio vulnificus hemolysin (VVH) is thought to be a member of the cholesterol-dependent cytolysin (CDC) family of pore-forming toxins. To date, the structure-function relationships of CDCs produced by Gram-negative bacteria remain largely unknown. We show here that the aromatic ring of phenylalanine residue conserved in Vibrionaceae hemolysins is essential for oligomerization of VVH. We generated the VVH mutants; substituted Phe 334 for Ile (F334I), Ala (F334A), Tyr (F334Y), or Trp (F334W); and tested their binding and oligomerizing activity on Chinese hamster ovary cells. Binding in all mutants fell by approximately 50% compared with that in the wild type. Oligomerizing activities were completely eliminated in F334I and F334A mutants, whereas this ability was partially retained in F334Y and F334W mutants. These findings indicate that both hydrophobicity and an aromatic ring residue at the 334th position were needed for full binding activity and that the oligomerizing activity of this toxin was dependent on the existence of an aromatic ring residue at the 334th position. Our findings might help further understanding of the structure-and-function relationships in Vibrionaceae hemolysins.
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39
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Sineva EV, Andreeva-Kovalevskaya ZI, Shadrin AM, Gerasimov YL, Ternovsky VI, Teplova VV, Yurkova TV, Solonin AS. Expression ofBacillus cereushemolysin II inBacillus subtilisrenders the bacteria pathogenic for the crustaceanDaphnia magna. FEMS Microbiol Lett 2009; 299:110-9. [DOI: 10.1111/j.1574-6968.2009.01742.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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40
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Stenfors Arnesen LP, Fagerlund A, Granum PE. From soil to gut:Bacillus cereusand its food poisoning toxins. FEMS Microbiol Rev 2008; 32:579-606. [DOI: 10.1111/j.1574-6976.2008.00112.x] [Citation(s) in RCA: 676] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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41
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Fagerlund A, Lindbäck T, Storset AK, Granum PE, Hardy SP. Bacillus cereus Nhe is a pore-forming toxin with structural and functional properties similar to the ClyA (HlyE, SheA) family of haemolysins, able to induce osmotic lysis in epithelia. MICROBIOLOGY-SGM 2008; 154:693-704. [PMID: 18310016 DOI: 10.1099/mic.0.2007/014134-0] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The mechanism by which Bacillus cereus causes diarrhoea is unknown. Three putative enterotoxins have been proposed, haemolysin BL (Hbl), cytotoxin K and non-haemolytic enterotoxin (Nhe). Both Hbl and Nhe are three-component cytotoxins and maximal cytotoxicity of Nhe against epithelia is dependent on all three components. However, little is known of the mechanism of cytotoxicity. Markers of plasma membrane disruption, namely propidium iodide uptake, loss of cellular ATP and release of lactate dehydrogenase (LDH), were observed in epithelia exposed to Nhe from culture supernatants of B. cereus, but not in those exposed to supernatants from a mutant strain lacking NheB and NheC. Consistent with an exogenous cause of membrane damage, purified Nhe components combined to form large conductance pores in planar lipid bilayers. The inhibition of LDH release by osmotic protectants and the increase in cell size caused by Nhe indicate that epithelia lyse following osmotic swelling. Nhe and Hbl show sequence homology, and Hbl component B has remarkable structural similarities to cytolysin A (ClyA), with both structures possessing an alpha-helix bundle and a unique subdomain containing a hydrophobic beta-hairpin. Correspondingly, we show that Nhe has haemolytic activity against erythrocytes from a variety of species. We propose that the common structural and functional properties indicate that the Hbl/Nhe and ClyA families of toxins constitute a superfamily of pore-forming cytotoxins.
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Affiliation(s)
- Annette Fagerlund
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway
| | - Toril Lindbäck
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway
| | - Anne K Storset
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway
| | - Per Einar Granum
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway
| | - Simon P Hardy
- Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science, PO Box 8146 Dep., N-0033 Oslo, Norway
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42
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Das SK, Darshi M, Cheley S, Wallace MI, Bayley H. Membrane protein stoichiometry determined from the step-wise photobleaching of dye-labelled subunits. Chembiochem 2007; 8:994-9. [PMID: 17503420 DOI: 10.1002/cbic.200600474] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Somes K Das
- Department of Molecular & Cellular Medicine, The Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
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43
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Shim JW, Yang M, Gu LQ. In vitro synthesis, tetramerization and single channel characterization of virus-encoded potassium channel Kcv. FEBS Lett 2007; 581:1027-34. [PMID: 17316630 DOI: 10.1016/j.febslet.2007.02.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 02/02/2007] [Accepted: 02/02/2007] [Indexed: 10/23/2022]
Abstract
Chlorella virus-encoded membrane protein Kcv represents a new class of potassium channel. This 94-amino acids miniature K(+) channel consists of two trans-membrane alpha-helix domains intermediated by a pore domain that contains a highly conserved K(+) selectivity filter. Therefore, as an archetypal K(+) channel, the study of Kcv may yield valuable insights into the structure-function relationships underlying this important class of ion channel. Here, we report a series of new properties of Kcv. We first verified Kcv can be synthesized in vitro. By co-synthesis and assembly of wild-type and the tagged version of Kcv, we were able to demonstrate a tetrameric stoichiometry, a molecular structure adopted by all known K(+) channels. Most notably, the tetrameric Kcv complex retains its functional integrity in SDS (strong detergent)-containing solutions, a useful feature that allows for direct purification of protein from polyacrylamide gel. Once purified, the tetramer can form single potassium-selective ion channels in a lipid bilayer with functions consistent to the heterologously expressed Kcv. These finding suggest that the synthetic Kcv can serve as a model of virus-encoded K(+) channels; and its newly identified properties can be applied to the future study on structure-determined mechanisms such as K(+) channel functional stoichiometry.
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Affiliation(s)
- Ji Wook Shim
- Department of Biological Engineering, Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO 65211, USA
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44
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Andreeva ZI, Nesterenko VF, Fomkina MG, Ternovsky VI, Suzina NE, Bakulina AY, Solonin AS, Sineva EV. The properties of Bacillus cereus hemolysin II pores depend on environmental conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1768:253-63. [PMID: 17173854 DOI: 10.1016/j.bbamem.2006.11.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 11/03/2006] [Accepted: 11/03/2006] [Indexed: 11/29/2022]
Abstract
Hemolysin II (HlyII), one of several cytolytic proteins encoded by the opportunistic human pathogen Bacillus cereus, is a member of the family of oligomeric beta-barrel pore-forming toxins. This work has studied the pore-forming properties of HlyII using a number of biochemical and biophysical approaches. According to electron microscopy, HlyII protein interacts with liposomes to form ordered heptamer-like macromolecular assemblies with an inner pore diameter of 1.5-2 nm and an outer diameter of 6-8 nm. This is consistent with inner pore diameter obtained from osmotic protection assay. According to the 3D model obtained, seven HlyII monomers might form a pore, the outer size of which has been estimated to be slightly larger than by the other method, with an inner diameter changing from 1 to 4 nm along the channel length. The hemolysis rate has been found to be temperature-dependent, with an explicit lag at lower temperatures. Temperature jump experiments have indicated the pore structures formed at 37 degrees C and 4 degrees C to be different. The channels formed by HlyII are anion-selective in lipid bilayers and show a rising conductance as the salt concentration increases. The results presented show for the first time that at high salt concentration HlyII pores demonstrate voltage-induced gating observed at low negative potentials. Taken together we have found that the membrane-binding properties of hemolysin II as well as the properties of its pores strongly depend on environmental conditions. The study of the properties together with structural modeling allows a better understanding of channel functioning.
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Affiliation(s)
- Zhanna I Andreeva
- Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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45
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Cheley S, Xie H, Bayley H. A Genetically Encoded Pore for the Stochastic Detection of a Protein Kinase. Chembiochem 2006; 7:1923-7. [PMID: 17068836 DOI: 10.1002/cbic.200600274] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Stochastic sensing is an emerging approach for the detection of a wide variety of analytes at the level of individual molecules. Detection is accomplished by observing the modulation of the current that flows through a single protein pore that has been engineered to bind an analyte of interest. Previously, protein analytes have been detected by using pores to which ligands have been appended at specific sites by targeted chemical modification. Here, we report the first genetically encoded stochastic sensor element for detecting a protein. A protein kinase inhibitor peptide sequence was incorporated into the alpha-hemolysin polypeptide, which was used to form a heteroheptameric pore containing a single copy of the inhibitor sequence. With this pore, the successful detection of the catalytic subunit of protein kinase A was demonstrated. This development should greatly facilitate the detection of active kinase subunits by stochastic sensing and the rapid screening of kinase inhibitors by an approach that yields kinetic information.
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Affiliation(s)
- Stephen Cheley
- Department of Molecular and Cellular Medicine, The Texas A&M University System Health Science Center, College Station, TX 77843-1114, USA
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46
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Nanoarray-Surfaces by Reconstitution of the Porin MspA into Stabilized Long-Chain-Lipid-Monolayers at a Gold-Surface. ELECTROANAL 2006. [DOI: 10.1002/elan.200603636] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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47
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Hendriksen NB, Hansen BM, Johansen JE. Occurrence and pathogenic potential of Bacillus cereus group bacteria in a sandy loam. Antonie van Leeuwenhoek 2006; 89:239-49. [PMID: 16710635 DOI: 10.1007/s10482-005-9025-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Accepted: 11/17/2005] [Indexed: 10/24/2022]
Abstract
The major part (94%) of the Bacillus cereus-like isolates from a Danish sandy loam are psychrotolerant Bacillus weihenstephanensis according to their ability to grow at temperatures below 7 degrees C and/or two PCR-based methods, while the remaining 6% are B. cereus. The Bacillus mycoides-like isolates could also be divided into psychrotolerant and mesophilic isolates. The psychrotolerant isolates of B. mycoides could be discriminated from the mesophilic by the two PCR-based methods used to characterize B. weihenstephanensis. It is likely that the mesophilic B. mycoides strains are synonymous with Bacillus pseudomycoides, while psychrotolerant B. weihenstephanensis, like B. mycoides, are B. mycoides senso stricto. B. cereus is known to produce a number of factors, which are involved in its ability to cause gastrointestinal and somatic diseases. All the B. cereus-like and B. mycoides like isolates from the sandy loam were investigated by PCR for the presence of 12 genes encoding toxins. Genes for the enterotoxins (hemolysin BL and nonhemolytic enterotoxin) and the two of the enzymes (cereolysin AB) were present in the major part of the isolates, while genes for phospolipase C and hemolysin III were present in fewer isolates, especially among B. mycoides like isolates. Genes for cytotoxin K and the hemolysin II were only present in isolates affiliated to B. cereus. Most of the mesophilic B. mycoides isolates did not possess the genes for the nonhemolytic enterotoxin and the cereolysin AB. The presence of multiple genes coding for virulence factors in all the isolates from the B. cereus group suggests that all the isolates from the sandy loam are potential pathogens.
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Affiliation(s)
- Niels Bohse Hendriksen
- Department of Environmental Chemistry and Microbiology, National Environmental Research Institute, Frederiksborgvej 399, P.O. Box 358, DK-4000, Roskilde, Denmark.
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48
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Jayasinghe L, Bayley H. The leukocidin pore: evidence for an octamer with four LukF subunits and four LukS subunits alternating around a central axis. Protein Sci 2005; 14:2550-61. [PMID: 16195546 PMCID: PMC2253299 DOI: 10.1110/ps.051648505] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The staphylococcal alpha-hemolysin (alphaHL) and leukocidin (Luk) polypeptides are members of a family of related beta-barrel pore-forming toxins. Upon binding to susceptible cells, alphaHL forms water-filled homoheptameric transmembrane pores. By contrast, Luk pores are formed by two classes of subunit, F and S, rendering a heptameric structure displeasing on symmetry grounds at least. Both the subunit stoichiometry and arrangement within the Luk pore have been contentious issues. Here we use chemical and genetic approaches to show that (1) the predominant, or perhaps the only, form of the Luk pore is an octamer; (2) the subunit stoichiometry is 1:1; and (3) the subunits are arranged in an alternating fashion about a central axis of symmetry, at least when a fused LukS-LukF construct is used. The experimental approaches we have used also open up new avenues for engineering the arrangement of the subunits of beta-barrel pore-forming toxins.
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Affiliation(s)
- Lakmal Jayasinghe
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, England, United Kingdom
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49
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Andreeva ZI, Nesterenko VF, Yurkov IS, Budarina ZI, Sineva EV, Solonin AS. Purification and cytotoxic properties of Bacillus cereus hemolysin II. Protein Expr Purif 2005; 47:186-93. [PMID: 16380268 DOI: 10.1016/j.pep.2005.10.030] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 10/25/2005] [Accepted: 10/30/2005] [Indexed: 10/25/2022]
Abstract
The hemolysin II from Bacillus cereus, HlyII, is a member of the beta-barrel pore-forming toxin family of secreted microbial proteins that includes the Staphylococcus aureus alpha-toxin. Compared with other proteins of the family, hemolysin II has 90 extra amino acids at its C-terminus. To examine more closely the cytotoxic and pore-forming properties of the protein, we have cloned and expressed it in Escherichia coli. We developed a purification procedure for the matured HlyII protein from both culture media and cell extracts using a combination of cation exchange and affinity chromatography together with gel-filtration. In both cases, the fully processed HlyII protein was purified as confirmed by N-terminal sequence analysis. The HlyII protein exhibits cytolytic activity of different extent on erythrocytes from various kinds of mammals. The results presented here show for the first time that two types of human cells are sensitive to HlyII action. In view of its broad cytotoxic activity as well as the ability to interact with artificial membranes, we assume that HlyII needs no specific receptor to bind to cell membranes.
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Affiliation(s)
- Zhanna I Andreeva
- Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, pr. Nauki, 5, Moscow Region 142290, Russia
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50
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Budarina ZI, Nikitin DV, Zenkin N, Zakharova M, Semenova E, Shlyapnikov MG, Rodikova EA, Masyukova S, Ogarkov O, Baida GE, Solonin AS, Severinov K. A new Bacillus cereus DNA-binding protein, HlyIIR, negatively regulates expression of B. cereus haemolysin II. MICROBIOLOGY-SGM 2005; 150:3691-3701. [PMID: 15528656 DOI: 10.1099/mic.0.27142-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Haemolysin II, HlyII, is one of several cytotoxic proteins produced by Bacillus cereus, an opportunistic human pathogen that causes food poisoning. The hlyII gene confers haemolytic activity to Escherichia coli cells. Here a new B. cereus gene, hlyIIR, which is located immediately downstream of hlyII and regulates hlyII expression, is reported. The deduced amino acid sequence of HlyIIR is similar to prokaryotic DNA-binding transcriptional regulators of the TetR/AcrA family. Measurements of haemolytic activity levels and of hlyII promoter activity levels using gene fusions and primer-extension assays demonstrated that, in E. coli, hlyII transcription decreased in the presence of hlyIIR. Recombinant HlyIIR binds to a 22 bp inverted DNA repeat centred 48 bp upstream of the hlyII promoter transcription initiation point. In vitro transcription studies showed that HlyIIR inhibits transcription from the hlyII promoter by binding to the 22 bp repeat and RNA polymerase, and by decreasing the formation of the catalytically competent open promoter complex.
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Affiliation(s)
- Zhanna I Budarina
- The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia
| | - Dmitri V Nikitin
- The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia
| | - Nikolay Zenkin
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Marina Zakharova
- The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia
| | - Ekaterina Semenova
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Michael G Shlyapnikov
- The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia
| | | | - Svetlana Masyukova
- The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia
| | - Oleg Ogarkov
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Gleb E Baida
- The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia
| | - Alexander S Solonin
- The Institute of Biochemistry and Physiology of Micro-organisms, Nauki Avenue, 5, Pushchino, 142292 Russia
| | - Konstantin Severinov
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA
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