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Prokaryotic Na+/H+ Exchangers—Transport Mechanism and Essential Residues. Int J Mol Sci 2022; 23:ijms23169156. [PMID: 36012428 PMCID: PMC9408914 DOI: 10.3390/ijms23169156] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/09/2022] [Accepted: 08/13/2022] [Indexed: 11/16/2022] Open
Abstract
Na+/H+ exchangers are essential for Na+ and pH homeostasis in all organisms. Human Na+/H+ exchangers are of high medical interest, and insights into their structure and function are aided by the investigation of prokaryotic homologues. Most prokaryotic Na+/H+ exchangers belong to either the Cation/Proton Antiporter (CPA) superfamily, the Ion Transport (IT) superfamily, or the Na+-translocating Mrp transporter superfamily. Several structures have been solved so far for CPA and Mrp members, but none for the IT members. NhaA from E. coli has served as the prototype of Na+/H+ exchangers due to the high amount of structural and functional data available. Recent structures from other CPA exchangers, together with diverse functional information, have allowed elucidation of some common working principles shared by Na+/H+ exchangers from different families, such as the type of residues involved in the substrate binding and even a simple mechanism sufficient to explain the pH regulation in the CPA and IT superfamilies. Here, we review several aspects of prokaryotic Na+/H+ exchanger structure and function, discussing the similarities and differences between different transporters, with a focus on the CPA and IT exchangers. We also discuss the proposed transport mechanisms for Na+/H+ exchangers that explain their highly pH-regulated activity profile.
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Haja DK, Adams MWW. pH Homeostasis and Sodium Ion Pumping by Multiple Resistance and pH Antiporters in Pyrococcus furiosus. Front Microbiol 2021; 12:712104. [PMID: 34484150 PMCID: PMC8415708 DOI: 10.3389/fmicb.2021.712104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/23/2021] [Indexed: 11/13/2022] Open
Abstract
Multiple Resistance and pH (Mrp) antiporters are seven-subunit complexes that couple transport of ions across the membrane in response to a proton motive force (PMF) and have various physiological roles, including sodium ion sensing and pH homeostasis. The hyperthermophilic archaeon Pyrococcus furiosus contains three copies of Mrp encoding genes in its genome. Two are found as integral components of two respiratory complexes, membrane bound hydrogenase (MBH) and the membrane bound sulfane sulfur reductase (MBS) that couple redox activity to sodium translocation, while the third copy is a stand-alone Mrp. Sequence alignments show that this Mrp does not contain an energy-input (PMF) module but contains all other predicted functional Mrp domains. The P. furiosus Mrp deletion strain exhibits no significant changes in optimal pH or sodium ion concentration for growth but is more sensitive to medium acidification during growth. Cell suspension hydrogen gas production assays using the deletion strain show that this Mrp uses sodium as the coupling ion. Mrp likely maintains cytoplasmic pH by exchanging protons inside the cell for extracellular sodium ions. Deletion of the MBH sodium-translocating module demonstrates that hydrogen gas production is uncoupled from ion pumping and provides insights into the evolution of this Mrp-containing respiratory complex.
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Affiliation(s)
- Dominik K Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
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Functional Characterization of Multiple Ehrlichia chaffeensis Sodium (Cation)/Proton Antiporter Genes Involved in the Bacterial pH Homeostasis. Int J Mol Sci 2021; 22:ijms22168420. [PMID: 34445146 PMCID: PMC8395091 DOI: 10.3390/ijms22168420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 11/16/2022] Open
Abstract
Ehrlichia chaffeensis causes human monocytic ehrlichiosis. Little is known about how this and other related tick-borne rickettsia pathogens maintain pH homeostasis in acidified phagosomes and the extracellular milieu. The membrane-bound sodium (cation)/proton antiporters are found in a wide range of organisms aiding pH homeostasis. We recently reported a mutation in an antiporter gene of E. chaffeensis (ECH_0379) which causes bacterial in vivo attenuation. The E. chaffeensis genome contains 10 protein coding sequences encoding for predicted antiporters. We report here that nine of these genes are transcribed during the bacterial growth in macrophages and tick cells. All E. chaffeensis antiporter genes functionally complemented antiporter deficient Escherichia coli. Antiporter activity for all predicted E. chaffeensis genes was observed at pH 5.5, while gene products of ECH_0179 and ECH_0379 were also active at pH 8.0, and ECH_0179 protein was complemented at pH 7.0. The antiporter activity was independently verified for the ECH_0379 protein by proteoliposome diffusion analysis. This is the first description of antiporters in E. chaffeensis and demonstrates that the pathogen contains multiple antiporters with varying biological functions, which are likely important for the pH homeostasis of the pathogen’s replicating and infectious forms.
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Markones M, Fippel A, Kaiser M, Drechsler C, Hunte C, Heerklotz H. Stairway to Asymmetry: Five Steps to Lipid-Asymmetric Proteoliposomes. Biophys J 2020; 118:294-302. [PMID: 31843262 PMCID: PMC6976795 DOI: 10.1016/j.bpj.2019.10.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/09/2019] [Accepted: 10/28/2019] [Indexed: 12/15/2022] Open
Abstract
Membrane proteins are embedded in a complex lipid environment that influences their structure and function. One key feature of nearly all biological membranes is a distinct lipid asymmetry. However, the influence of membrane asymmetry on proteins is poorly understood, and novel asymmetric proteoliposome systems are beneficial. To our knowledge, we present the first study on a multispanning protein incorporated in large unilamellar liposomes showing a stable lipid asymmetry. These asymmetric proteoliposomes contain the Na+/H+ antiporter NhaA from Salmonella Typhimurium. Asymmetry was introduced by partial, outside-only exchange of anionic phosphatidylglycerol (PG), mimicking this key asymmetry of bacterial membranes. Outer-leaflet and total fractions of PG were determined via ζ-potential (ζ) measurements after lipid exchange and after scrambling of asymmetry. ζ-Values were in good agreement with exclusive outside localization of PG. The electrogenic Na+/H+ antiporter was active in asymmetric liposomes, and it can be concluded that reconstitution and generation of asymmetry were successful. Lipid asymmetry was stable for more than 7 days at 23°C and thus enabled characterization of the Na+/H+ antiporter in an asymmetric lipid environment. We present and validate a simple five-step protocol that addresses key steps to be taken and pitfalls to be avoided for the preparation of asymmetric proteoliposomes: 1) optimization of desired lipid composition, 2) detergent-mediated protein reconstitution with subsequent detergent removal, 3) generation of lipid asymmetry by partial exchange of outer-leaflet lipid, 4) verification of lipid asymmetry and stability, and 5) determination of protein activity in the asymmetric lipid environment. This work offers guidance in designing asymmetric proteoliposomes that will enable researchers to compare functional and structural properties of membrane proteins in symmetric and asymmetric lipid environments.
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Affiliation(s)
- Marie Markones
- Institute for Pharmaceutical Sciences, University of Freiburg, Breisgau, Germany; Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Breisgau, Germany; HSGS Hermann Staudinger Graduate School, University of Freiburg, Breisgau, Germany.
| | - Anika Fippel
- Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Breisgau, Germany; HSGS Hermann Staudinger Graduate School, University of Freiburg, Breisgau, Germany
| | - Michael Kaiser
- Institute for Pharmaceutical Sciences, University of Freiburg, Breisgau, Germany; HSGS Hermann Staudinger Graduate School, University of Freiburg, Breisgau, Germany
| | - Carina Drechsler
- Institute for Pharmaceutical Sciences, University of Freiburg, Breisgau, Germany; Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Breisgau, Germany
| | - Carola Hunte
- Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Breisgau, Germany; Institute for Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Breisgau, Germany
| | - Heiko Heerklotz
- Institute for Pharmaceutical Sciences, University of Freiburg, Breisgau, Germany; Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Breisgau, Germany; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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5
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Anes J, Sivasankaran SK, Muthappa DM, Fanning S, Srikumar S. Exposure to Sub-inhibitory Concentrations of the Chemosensitizer 1-(1-Naphthylmethyl)-Piperazine Creates Membrane Destabilization in Multi-Drug Resistant Klebsiella pneumoniae. Front Microbiol 2019; 10:92. [PMID: 30814979 PMCID: PMC6381021 DOI: 10.3389/fmicb.2019.00092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/16/2019] [Indexed: 01/23/2023] Open
Abstract
Antimicrobial efflux is one of the important mechanisms causing multi-drug resistance (MDR) in bacteria. Chemosensitizers like 1-(1-naphthylmethyl)-piperazine (NMP) can inhibit an efflux pump and therefore can overcome MDR. However, secondary effects of NMP other than efflux pump inhibition are rarely investigated. Here, using phenotypic assays, phenotypic microarray and transcriptomic assays we show that NMP creates membrane destabilization in MDR Klebsiella pneumoniae MGH 78578 strain. The NMP mediated membrane destabilization activity was measured using β-lactamase activity, membrane potential alteration studies, and transmission electron microscopy assays. Results from both β-lactamase and membrane potential alteration studies shows that both outer and inner membranes are destabilized in NMP exposed K. pneumoniae MGH 78578 cells. Phenotypic Microarray and RNA-seq were further used to elucidate the metabolic and transcriptional signals underpinning membrane destabilization. Membrane destabilization happens as early as 15 min post-NMP treatment. Our RNA-seq data shows that many genes involved in envelope stress response were differentially regulated in the NMP treated cells. Up-regulation of genes encoding the envelope stress response and repair systems show the distortion in membrane homeostasis during survival in an environment containing sub-inhibitory concentration of NMP. In addition, the lsr operon encoding the production of autoinducer-2 responsible for biofilm production was down-regulated resulting in reduced biofilm formation in NMP treated cells, a phenotype confirmed by crystal violet-based assays. We postulate that the early membrane disruption leads to destabilization of inner membrane potential, impairing ATP production and consequently resulting in efflux pump inhibition.
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Affiliation(s)
- João Anes
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
| | | | - Dechamma M Muthappa
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
| | - Séamus Fanning
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland.,Institute for Global Food Security, Queen's University Belfast, Belfast, United Kingdom
| | - Shabarinath Srikumar
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
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Patiño-Ruiz M, Dwivedi M, Călinescu O, Karabel M, Padan E, Fendler K. Replacement of Lys-300 with a glutamine in the NhaA Na +/H + antiporter of Escherichia coli yields a functional electrogenic transporter. J Biol Chem 2019; 294:246-256. [PMID: 30409911 PMCID: PMC6322889 DOI: 10.1074/jbc.ra118.004903] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/06/2018] [Indexed: 01/28/2023] Open
Abstract
Much of the research on Na+/H+ exchange has been done in prokaryotic models, mainly on the NhaA Na+/H+-exchanger from Escherichia coli (EcNhaA). Two conserved aspartate residues, Asp-163 and Asp-164, are essential for transport and are candidates for possible binding sites for the two H+ that are exchanged for one Na+ to make the overall transport process electrogenic. More recently, a proposed mechanism of transport for EcNhaA has suggested direct binding of one of the transported H+ to the conserved Lys-300 residue, a salt bridge partner of Asp-163. This contention is supported by a study reporting that substitution of the equivalent residue, Lys-305, of a related Na+/H+ antiporter, NapA from Thermus thermophilus, renders the transporter electroneutral. In this work, we sought to establish whether the Lys-300 residue and its partner Asp-163 are essential for the electrogenicity of EcNhaA. To that end, we replaced Lys-300 with Gln, either alone or together with the simultaneous substitution of Asp-163 with Asn, and characterized these transporter variants in electrophysiological experiments combined with H+ transport measurements and stability analysis. We found that K300Q EcNhaA can still support electrogenic Na+/H+ antiport in EcNhaA, but has reduced thermal stability. A parallel electrophysiological investigation of the K305Q variant of TtNapA revealed that it is also electrogenic. Furthermore, replacement of both salt bridge partners in the ion-binding site of EcNhaA produced an electrogenic variant (D163N/K300Q). Our findings indicate that alternative mechanisms sustain EcNhaA activity in the absence of canonical ion-binding residues and that the conserved lysines confer structural stability.
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Affiliation(s)
- Miyer Patiño-Ruiz
- Max-Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Manish Dwivedi
- Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Octavian Călinescu
- Max-Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany; Department of Biophysics, "Carol Davila" University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Mehmet Karabel
- Max-Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Etana Padan
- Institute of Life Sciences, Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Klaus Fendler
- Max-Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany.
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7
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Dawut K, Sirisattha S, Hibino T, Kageyama H, Waditee-Sirisattha R. Functional characterization of the NhaA Na +/H + antiporter from the green picoalga Ostreococcus tauri. Arch Biochem Biophys 2018; 649:37-46. [PMID: 29730321 DOI: 10.1016/j.abb.2018.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 12/13/2022]
Abstract
Transmembrane ion transport is a critical process in the cellular response to salt stress. Among the known functional membrane transporters that are involved in the salt stress response, Na+/H+ antiporters have been extensively studied. These ubiquitous membrane proteins are crucial for salt tolerance and are associated with the regulation of internal pH, cell volume, morphogenesis, and vesicular trafficking. Molecular and functional analyses of Na+/H+ antiporters have been characterized among taxa but little is known about algal Na+/H+ antiporters. Here, we analyzed putative Na+/H+ antiporters from the complete genome sequence of the marine picoalga Ostreococcus tauri. At least 10 putative Na+/H+ antiporters belonging to the SOS1, NHX, and KEA/Kef families were found. Surprisingly, a bacterial type NhaA sequence (OtNhaA) was also found. Topological modeling of OtNhaA predicted 12 possible transmembrane segments with a long N-terminus. The full-length (FL_OtNhaA) and N-terminal truncated (ΔN112_OtNhaA) versions of OtNhaA were constructed, expressed in the salt-sensitive mutant Escherichia coli TO114, and functionally characterized. Complementation analysis revealed that FL_OtNhaA- and ΔN112_OtNhaA-expressing cells exhibited increased tolerance to high NaCl concentrations up to 700 mM. Antiporter activity assays showed that both FL_OtNhaA and ΔN112_OtNhaA proteins predominantly exhibited Na+/H+ and Ca2+/H+ antiporter activities at alkaline pH conditions. Intriguingly, the ΔN112_OtNhaA exhibited higher Na+/H+ and Ca2+/H+ antiporter activities compared to FL_OtNhaA. Kinetic analysis revealed that FL_OtNhaA has a high affinity for Na+ and Ca2+ ions with a Km of 1.1 ± 0.23 mM for Na+ (at pH 8.5) and a Km of 0.3 ± 0.07 mM for Ca2+ (at pH 8.5). Since NhaA has shown striking diversity among taxa, our results provide insight into the functional properties of the algal NhaA Na+/H+ antiporter. These results will contribute to the understanding of Na+/H+ antiporters that have various implications in all kingdoms of life.
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Affiliation(s)
- Keatisuda Dawut
- Department of Microbiology, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand; Program in Biotechnology, Faculty of Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
| | - Sophon Sirisattha
- Thailand Institute of Scientific and Technological Research (TISTR), Pathum Thani 12120, Thailand
| | - Takashi Hibino
- Department of Chemistry, Faculty of Science and Technology, Meijo University, Nagoya, Aichi 468-8502, Japan
| | - Hakuto Kageyama
- Department of Chemistry, Faculty of Science and Technology, Meijo University, Nagoya, Aichi 468-8502, Japan.
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A genetic system for targeted mutations to disrupt and restore genes in the obligate bacterium, Ehrlichia chaffeensis. Sci Rep 2017; 7:15801. [PMID: 29150636 PMCID: PMC5693922 DOI: 10.1038/s41598-017-16023-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/02/2017] [Indexed: 11/17/2022] Open
Abstract
Obligate intracellular bacteria (obligates) belonging to Rickettsiales and Chlamydiales cause diseases in hundreds of millions of people worldwide and in many animal species. Lack of an efficient system for targeted mutagenesis in obligates remains a major impediment in understanding microbial pathogenesis. Challenges in creating targeted mutations may be attributed to essential nature of majority of the genes and intracellular replication dependence. Despite success in generating random mutations, a method that works well in creating mutations in specific genes of interest followed by complementation remains problematic for obligates and is a highly sought-after goal. We describe protocols to generate stable targeted mutations by allelic exchange in Ehrlichia chaffeensis, an obligate intracellular tick-borne bacterium responsible for human monocytic ehrlichiosis. Targeted mutations in E. chaffeensis were created to disrupt two genes, and also to restore one gene by another allelic exchange mutation leading to the restoration of transcription and protein expression from the inactivated gene and the recovered organisms also express mCherry, which distinguishes from the wild type. We expect that the methods developed are broadly applicable to other obligates, particularly to rickettsial pathogens, to routinely perform targeted mutations to enable studies focused on protein structure-function analyses, host-pathogen interactions and in developing vaccines.
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9
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Patiño-Ruiz M, Ganea C, Fendler K, Călinescu O. Competition is the basis of the transport mechanism of the NhaB Na+/H+ exchanger from Klebsiella pneumoniae. PLoS One 2017; 12:e0182293. [PMID: 28750048 PMCID: PMC5531510 DOI: 10.1371/journal.pone.0182293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 07/14/2017] [Indexed: 11/18/2022] Open
Abstract
Na+/H+ exchange is essential for survival of all organisms, having a role in the regulation of the intracellular Na+ concentration, pH and cell volume. Furthermore, Na+/H+ exchangers were shown to be involved in the virulence of the bacterium Yersinia pestis, indicating they might be potential targets for novel antibiotic treatments. The model system for Na+/H+ exchangers is the NhaA transporter from Escherichia coli, EcNhaA. Therefore, the general transport mechanism of NhaA exchangers is currently well characterized. However, much less is known about NhaB exchangers, with only a limited number of studies available. The pathogen Klebsiella pneumoniae, which is a major source of nosocomial infection, possesses three electrogenic Na+/H+ exchangers, KpNhaA1, KpNhaA2 and KpNhaB, none of which have been previously investigated. Our aim in this study was to functionally characterize KpNhaB using solid supported membrane-based electrophysiology as the main investigation technique, and thus provide the first electrophysiological investigation of an NhaB Na+/H+ exchanger. We found that NhaB can be described by the same competition-based mechanism that was shown to be valid for electrogenic NhaA and NapA, and for electroneutral NhaP Na+/H+ exchangers. For comparison we also characterized the activity of KpNhaA1 and KpNhaA2 and found that the three exchangers have complementary activity profiles, which is likely a survival advantage for K. pneumoniae when faced with environments of different salinity and pH. This underlines their importance as potential antibiotic drug targets.
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Affiliation(s)
- Miyer Patiño-Ruiz
- Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Constanța Ganea
- Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
- Department of Biophysics, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
| | - Klaus Fendler
- Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Octavian Călinescu
- Department of Biophysical Chemistry, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
- Department of Biophysics, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania
- * E-mail:
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Functional Interaction between the N and C Termini of NhaD Antiporters from Halomonas sp. Strain Y2. J Bacteriol 2017; 199:JB.00302-17. [PMID: 28559301 DOI: 10.1128/jb.00302-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 05/23/2017] [Indexed: 02/04/2023] Open
Abstract
Two NhaD-type antiporters, NhaD1 and NhaD2, from the halotolerant and alkaliphilic Halomonas sp. strain Y2, exhibit different physiological functions in regard to Na+ and Li+ resistance, although they share high sequence identity. In the present study, the truncation of an additional 4 C-terminal residues from NhaD2 or an exchange of 39 N-terminal residues between these proteins resulted in the complete loss of antiporter activity. Interestingly, combining 39 N-terminal residues and 7 C-terminal residues of NhaD2 (N39D2-C7) partially recovered the activity for Na+ and Li+ expulsion, as well as complementary growth following exposure to 300 mM Na+ and 100 mM Li+ stress. The recovered activity of chimera N39D2-C7 indicated that the N and C termini are structurally dependent on each other and function synergistically. Furthermore, fluorescence resonance energy transfer (FRET) analysis suggested that the N and C termini are relatively close in proximity which may account for their synergistic function in ion translocation. In the N-terminal region of N39D2-C7, the replacement of Glu38 with Pro abolished the recovered complementary and transport activities. In addition, this amino acid substitution in NhaD2 resulted in a drastically decreased complementation ability in Escherichia coli KNabc (level identical to that of NhaD1), as well as decreased activity and an altered pH profile.IMPORTANCE Limited information on NhaD antiporters supports speculation that these antiporters are important for resistance to high salinity and alkalinity. Moreover, only a few functional residues have been identified in NhaD antiporters, and there is limited literature on the molecular mechanisms of NhaD antiporter activity. The altered antiporter abilities of chimeras and mutants in this study implicate the functions of the N and C termini, especially Glu38, in pH regulation and ion translocation, and, most importantly, the essential roles of this negatively charged residue in maintaining the physiological function of NhaD2. These findings further our understanding of the molecular mechanism of NhaD antiporters for ion transport.
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Szermer-Olearnik B, Drab M, Mąkosa M, Zembala M, Barbasz J, Dąbrowska K, Boratyński J. Aggregation/dispersion transitions of T4 phage triggered by environmental ion availability. J Nanobiotechnology 2017; 15:32. [PMID: 28438164 PMCID: PMC5404661 DOI: 10.1186/s12951-017-0266-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 04/10/2017] [Indexed: 11/24/2022] Open
Abstract
Background Bacteriophage survives in at least two extremes of ionic environments: bacterial host (high ionic-cytosol) and that of soil (low ionic-environmental water). The impact of ionic composition in the micro- and macro-environments has not so far been addressed in phage biology. Results Here, we discovered a novel mechanism of aggregation/disaggregation transitions by phage virions. When normal sodium levels in phage media (150 mM) were lowered to 10 mM, advanced imaging by scanning electron microscopy, atomic force microscopy and dynamic light scattering all revealed formation of viral packages, each containing 20–100 virions. When ionic strength was returned from low to high, the aggregated state of phage reversed to a dispersed state, and the change in ionic strength did not substantially affect infectivity of the phage. By providing the direct evidence, that lowering of the sodium ion below the threshold of 20 mM causes rapid aggregation of phage while returning Na+ concentration to the values above this threshold causes dispersion of phage, we identified a biophysical mechanism of phage aggregation. Conclusions Our results implicate operation of group behavior in phage and suggest a new kind of quorum sensing among its virions that is mediated by ions. Loss of ionic strength may act as a trigger in an evolutionary mechanism to improve the survival of bacteriophage by stimulating aggregation of phage when outside a bacterial host. Reversal of phage aggregation is also a promising breakthrough in biotechnological applications, since we demonstrated here the ability to retain viable virion aggregates on standard micro-filters.
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Affiliation(s)
- Bożena Szermer-Olearnik
- Laboratory of Biomedical Chemistry-"Neolek". Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114, Wroclaw, Poland
| | - Marek Drab
- USI, Unit of Nanostructural Bio-Interactions, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114, Wrocław, Poland
| | - Mateusz Mąkosa
- Laboratory of Biomedical Chemistry-"Neolek". Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114, Wroclaw, Poland
| | - Maria Zembala
- Institute of Biology, Pedagogical University of Cracow, Podchorążych 2, 30-084, Cracow, Poland
| | - Jakub Barbasz
- Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239, Cracow, Poland
| | - Krystyna Dąbrowska
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114, Wrocław, Poland
| | - Janusz Boratyński
- Laboratory of Biomedical Chemistry-"Neolek". Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114, Wroclaw, Poland. .,Institute of Chemistry, Environmental Protection and Biotechnology, Jan Długosz University, 42-200, Częstochowa, Poland.
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12
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Kao WC, Kleinschroth T, Nitschke W, Baymann F, Neehaul Y, Hellwig P, Richers S, Vonck J, Bott M, Hunte C. The obligate respiratory supercomplex from Actinobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1705-14. [PMID: 27472998 DOI: 10.1016/j.bbabio.2016.07.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 06/27/2016] [Accepted: 07/23/2016] [Indexed: 10/21/2022]
Abstract
Actinobacteria are closely linked to human life as industrial producers of bioactive molecules and as human pathogens. Respiratory cytochrome bcc complex and cytochrome aa3 oxidase are key components of their aerobic energy metabolism. They form a supercomplex in the actinobacterial species Corynebacterium glutamicum. With comprehensive bioinformatics and phylogenetic analysis we show that genes for cyt bcc-aa3 supercomplex are characteristic for Actinobacteria (Actinobacteria and Acidimicrobiia, except the anaerobic orders Actinomycetales and Bifidobacteriales). An obligatory supercomplex is likely, due to the lack of genes encoding alternative electron transfer partners such as mono-heme cyt c. Instead, subunit QcrC of bcc complex, here classified as short di-heme cyt c, will provide the exclusive electron transfer link between the complexes as in C. glutamicum. Purified to high homogeneity, the C. glutamicum bcc-aa3 supercomplex contained all subunits and cofactors as analyzed by SDS-PAGE, BN-PAGE, absorption and EPR spectroscopy. Highly uniform supercomplex particles in electron microscopy analysis support a distinct structural composition. The supercomplex possesses a dimeric stoichiometry with a ratio of a-type, b-type and c-type hemes close to 1:1:1. Redox titrations revealed a low potential bcc complex (Em(ISP)=+160mV, Em(bL)=-291mV, Em(bH)=-163mV, Em(cc)=+100mV) fined-tuned for oxidation of menaquinol and a mixed potential aa3 oxidase (Em(CuA)=+150mV, Em(a/a3)=+143/+317mV) mediating between low and high redox potential to accomplish dioxygen reduction. The generated molecular model supports a stable assembled supercomplex with defined architecture which permits energetically efficient coupling of menaquinol oxidation and dioxygen reduction in one supramolecular entity.
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Affiliation(s)
- Wei-Chun Kao
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, BIOSS Centre for Biological Signalling Studies, 79104 Freiburg, Germany
| | - Thomas Kleinschroth
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, BIOSS Centre for Biological Signalling Studies, 79104 Freiburg, Germany
| | - Wolfgang Nitschke
- Laboratoire de Bioénergétique et Ingénierie des Protéines UMR 7281 CNRS/Aix Marseille Univ, FR3479, 13009 Marseille, France
| | - Frauke Baymann
- Laboratoire de Bioénergétique et Ingénierie des Protéines UMR 7281 CNRS/Aix Marseille Univ, FR3479, 13009 Marseille, France
| | - Yashvin Neehaul
- Laboratoire de bioélectrochimie et spectroscopie, UMR 7140, Chimie de la matière complexe, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| | - Petra Hellwig
- Laboratoire de bioélectrochimie et spectroscopie, UMR 7140, Chimie de la matière complexe, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| | - Sebastian Richers
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany
| | - Michael Bott
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Carola Hunte
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, BIOSS Centre for Biological Signalling Studies, 79104 Freiburg, Germany.
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13
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Scaria J, Suzuki H, Ptak CP, Chen JW, Zhu Y, Guo XK, Chang YF. Comparative genomic and phenomic analysis of Clostridium difficile and Clostridium sordellii, two related pathogens with differing host tissue preference. BMC Genomics 2015; 16:448. [PMID: 26059449 PMCID: PMC4462011 DOI: 10.1186/s12864-015-1663-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 05/29/2015] [Indexed: 01/05/2023] Open
Abstract
Background Clostridium difficile and C. sordellii are two anaerobic, spore forming, gram positive pathogens with a broad host range and the ability to cause lethal infections. Despite strong similarities between the two Clostridial strains, differences in their host tissue preference place C. difficile infections in the gastrointestinal tract and C. sordellii infections in soft tissues. Results In this study, to improve our understanding of C. sordellii and C. difficile virulence and pathogenesis, we have performed a comparative genomic and phenomic analysis of the two. The global phenomes of C. difficile and C. sordellii were compared using Biolog Phenotype microarrays. When compared to C. difficile, C. sordellii was found to better utilize more complex sources of carbon and nitrogen, including peptides. Phenotype microarray comparison also revealed that C. sordellii was better able to grow in acidic pH conditions. Using next generation sequencing technology, we determined the draft genome of C. sordellii strain 8483 and performed comparative genome analysis with C. difficile and other Clostridial genomes. Comparative genome analysis revealed the presence of several enzymes, including the urease gene cluster, specific to the C. sordellii genome that confer the ability of expanded peptide utilization and survival in acidic pH. Conclusions The identified phenotypes of C. sordellii might be important in causing wound and vaginal infections respectively. Proteins involved in the metabolic differences between C. sordellii and C. difficile should be targets for further studies aimed at understanding C. difficile and C. sordellii infection site specificity and pathogenesis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1663-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Joy Scaria
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA. .,Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, 57007, USA.
| | - Haruo Suzuki
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA. .,Graduate School of Science and Engineering, Yamaguchi University, Yamaguchi, Japan.
| | - Christopher P Ptak
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
| | - Jenn-Wei Chen
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
| | - Yongzhang Zhu
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA. .,Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Xiao-Kui Guo
- Department of Medical Microbiology and Parasitology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Yung-Fu Chang
- Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
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Maqsood SR, Khan B, Bhat MA, Dar TA, Mir SH. Targeting copper induced oxidative damage to proteins by ligation: a novel approach towards chelation therapy for oxidative stress disorders. NEW J CHEM 2015. [DOI: 10.1039/c4nj02073a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
DIDE and rhodanine prevent the copper induced oxidative damage to proteins by binding copper into a redox inactive state.
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Affiliation(s)
| | - Badruddin Khan
- Department of Chemistry
- University of Kashmir
- Srinagar-190006
- India
| | | | - Tanveer Ali Dar
- Department of Clinical Biochemistry
- University of Kashmir
- Srinagar-190006
- India
| | - Syed Hussain Mir
- Institute for Biochemistry and Molecular Biology
- University of Freiburg
- D-79104 Freiburg
- Germany
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15
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Species differences in bacterial NhaA Na+/H+ exchangers. FEBS Lett 2014; 588:3111-6. [PMID: 25017436 DOI: 10.1016/j.febslet.2014.05.066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 04/30/2014] [Accepted: 05/02/2014] [Indexed: 11/20/2022]
Abstract
Bacteria have adapted their NhaA Na(+)/H(+) exchangers responsible for salt homeostasis to their different habitats. We present an electrophysiological and kinetic analysis of NhaA from Helicobacter pylori and compare it to the previously investigated exchangers from Escherichia coli and Salmonella typhimurium. Properties of all three transporters are described by a simple model using a single binding site for H(+) and Na(+). We show that H.pylori NhaA only has a small acidic shift of its pH-dependent activity profile compared to the other transporters and discuss why a more drastic change in its pH activity profile is not physiologically required.
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