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Qazi SJS, Turner RJ. Influence of quaternary cation compound on the size of the Escherichia coli small multidrug resistance protein, EmrE. Biochem Biophys Rep 2018; 13:129-140. [PMID: 29552647 PMCID: PMC5852267 DOI: 10.1016/j.bbrep.2018.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 12/04/2017] [Accepted: 02/05/2018] [Indexed: 11/26/2022] Open
Abstract
EmrE is a member of the small multidrug resistance (SMR) protein family in Escherichia coli. It confers resistance to a wide variety of quaternary cation compounds (QCCs) as an efflux transporter driven by the transmembrane proton motive force. We have expressed hexahistidinyl (His6) – myc epitope tagged EmrE, extracted it from membrane preparations using the detergent n-dodecyl-β-D-maltopyranoside (DDM), and purified it using nickel-affinity chromatography. The size of the EmrE protein, in DDM environment, was then examined in the presence and absence of a range of structurally different QCC ligands that varied in their chemical structure, charge and shape. We used dynamic light scattering and showed that the size and oligomeric state distributions are dependent on the type of QCC. We also followed changes in the Trp fluorescence and determined apparent dissociation constants (Kd). Overall, our in vitro analyses of epitope tagged EmrE demonstrated subtle but significant differences in the size distributions with different QCC ligands bound. Chemical shape of ligand has significant affect on binding. Shape of the ligand affects the multimeric state of EmrE. Binding affinities strongly depend upon the ligand shape. EmrE shows high plasticity of structure to accommodate a wide range of ligands.
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Affiliation(s)
- S Junaid S Qazi
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Raymond J Turner
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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Zonaro E, Lampis S, Turner RJ, Qazi SJS, Vallini G. Biogenic selenium and tellurium nanoparticles synthesized by environmental microbial isolates efficaciously inhibit bacterial planktonic cultures and biofilms. Front Microbiol 2015; 6:584. [PMID: 26136728 PMCID: PMC4468835 DOI: 10.3389/fmicb.2015.00584] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 05/27/2015] [Indexed: 11/13/2022] Open
Abstract
The present study deals with Se0- and Te0-based nanoparticles bio-synthesized by two selenite- and tellurite-reducing bacterial strains, namely Stenotrophomonas maltophilia SeITE02 and Ochrobactrum sp. MPV1, isolated from polluted sites. We evidenced that, by regulating culture conditions and exposure time to the selenite and tellurite oxyanions, differently sized zero-valent Se and Te nanoparticles were produced. The results revealed that these Se0 and Te0 nanoparticles possess antimicrobial and biofilm eradication activity against Escherichia coli JM109, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus ATCC 25923. In particular, Se0 nanoparticles exhibited antimicrobial activity at quite low concentrations, below that of selenite. Toxic effects of both Se0 and Te0 nanoparticles can be related to the production of reactive oxygen species upon exposure of the bacterial cultures. Evidence so far achieved suggests that the antimicrobial activity seems to be strictly linked to the dimensions of the nanoparticles: indeed, the highest activity was shown by nanoparticles of smaller sizes. In particular, it is worth noting how the bacteria tested in biofilm mode responded to the treatment by Se0 and Te0 nanoparticles with a susceptibility similar to that observed in planktonic cultures. This suggests a possible exploitation of both Se0 and Te0 nanoparticles as efficacious antimicrobial agents with a remarkable biofilm eradication capacity.
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Affiliation(s)
- Emanuele Zonaro
- Department of Biotechnology, University of Verona Verona, Italy ; Biofilm Research Group, Department of Biological Sciences, University of Calgary Calgary, AB, Canada
| | - Silvia Lampis
- Department of Biotechnology, University of Verona Verona, Italy
| | - Raymond J Turner
- Biofilm Research Group, Department of Biological Sciences, University of Calgary Calgary, AB, Canada
| | - S Junaid S Qazi
- Biofilm Research Group, Department of Biological Sciences, University of Calgary Calgary, AB, Canada
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Qazi SJS, Chew R, Bay DC, Turner RJ. Structural and functional comparison of hexahistidine tagged and untagged forms of small multidrug resistance protein, EmrE. Biochem Biophys Rep 2015; 1:22-32. [PMID: 29124131 PMCID: PMC5668558 DOI: 10.1016/j.bbrep.2015.03.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 03/13/2015] [Accepted: 03/18/2015] [Indexed: 02/04/2023] Open
Abstract
EmrE is a member of the small multidrug resistance (SMR) protein family in Escherichia coli. EmrE confers resistance to a wide variety of quaternary cation compounds (QCCs) as an efflux transporter driven by proton motive force. The purification yield of most membrane proteins are challenging because of difficulties in over expressing, isolating and solubilizing them and the addition of an affinity tag often improves purification. The purpose of this study is to compare the structure and function of hexahistidinyl (His6) tagged (T-EmrE) and untagged (UT-EmrE) versions of EmrE. In vivo QCC resistance assays determined that T-EmrE demonstrated reduced resistance as compared to UT-EmrE. We isolated EmrE using the two different purification methods, an organic solvent extraction method used to isolate UT-EmrE and nickel affinity chromatography of T-EmrE. All proteins were solubilized in the same buffered n-dodecyl-β-d-maltopyranoside (DDM) detergent and their conformations were examined in the presence/absence of different QCCs. In vitro analysis of protein multimerization using SDS-Tricine PAGE and dynamic light scattering analysis revealed that both proteins predominated as monomers, but the formation of dimers was more constant and uniform in T-EmrE compared to UT-EmrE. The aromatic residue conformations of both proteins indicate that T-EmrE form is more aqueous exposed than UT-EmrE, but UT-EmrE appeared to have a more dynamic environment surrounding its aromatic residues. Using fluorescence to obtain QCC ligand-binding curves indicated that the two forms had differences in dissociation constants (Kd) and maximum specific one-site binding (Bmax) values for particular QCCs. In vitro analyses of both proteins demonstrated subtle but significant differences in multimerization and QCC binding. In vivo analysis indicates differences caused by the addition of the tag, we also observed differences in vitro that could be a result of the tag and/or the different purification methods. Untagged and tagged EmrE are compared in same detergent environment. Purification methods leads to differences in multimeric state distributions. Untagged EmrE has a less constrained structure compared to tagged EmrE. Presence of a tag alters substrate binding to EmrE.
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Affiliation(s)
- S Junaid S Qazi
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Raymond Chew
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Denice C Bay
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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Chan CS, Song X, Qazi SJS, Setiaputra D, Yip CK, Chao TC, Turner RJ. Unusual pairing between assistants: interaction of the twin-arginine system-specific chaperone DmsD with the chaperonin GroEL. Biochem Biophys Res Commun 2015; 456:841-6. [PMID: 25522883 DOI: 10.1016/j.bbrc.2014.12.046] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 12/09/2014] [Indexed: 11/25/2022]
Abstract
DmsD is a system-specific chaperone that mediates the biogenesis and maturation of DMSO reductase in Escherichia coli. It is required for DmsAB holoenzyme formation and its targeting to the cytoplasmic membrane for translocation by the twin-arginine translocase. Previous studies suggested that DmsD also interacts with general molecular chaperones to assist in folding of the reductase subunits. Here, the interaction between DmsD and GroEL was further characterized to understand the role of GroEL in DMSO reductase maturation. The inherently weak interaction between the two was strengthened in vivo under growth conditions that induce DMSO reductase expression, and the DmsD-GroEL complex showed negligible change in hydrodynamic diameter by dynamic light scattering when cross-linked. Mapping the cross-linked sites on DmsD shows that the GroEL binding site is in close proximity to the previously characterized DmsA leader binding site. These findings support a role of GroEL in DMSO reductase maturation that likely involves its chaperonin function for assisting in folding of the DmsA preprotein.
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Affiliation(s)
- Catherine S Chan
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Xiao Song
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - S Junaid S Qazi
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Dheva Setiaputra
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Calvin K Yip
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Tzu-Chiao Chao
- Institute of Environmental Change and Society, University of Regina, Regina, Saskatchewan, Canada
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
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Abstract
Orientational alignment in a dilute dispersion of kaolinite particles has been investigated in a flow pattern that combines both shear and elongational stress, namely flow at a jet created by a 2 mm diameter nozzle inserted in a 6 mm diameter pipe. Spatially-resolved X-ray diffraction with synchrotron radiation permits detailed maps of the alignment to be deduced and compared with fluid mechanics calculations of the flow. The angular distribution of diffracted intensity from a given position in the pipe provides information about the orientation distribution of the particles. This is quantified and presented in terms of order parameters. The cone-shaped nozzle provides a jet of liquid giving a high degree of alignment of the particles that is uniform along lines across the conical section and constant in the small straight-sided region at the exit of the nozzle. The vortex motion that arises from the flow with a modest Reynolds number could be determined as well as the tendency for some particles to align with their large faces perpendicular to the overall flow direction at the flat surface of the nozzle outlet.
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Affiliation(s)
- S Junaid S Qazi
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden.
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Qazi SJS, Rennie AR, Tucker I, Penfold J, Grillo I. Impact of Ni(OH)2 Platelike Particles on Lamellar Surfactant Mesophases and the Orientation of Their Mixtures under Elongational Flow. J Phys Chem B 2011; 115:10413-24. [DOI: 10.1021/jp2037069] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Ian Tucker
- Unilever Research and Development, Port Sunlight Laboratory, Quarry Road East, Bebington, Wirral CH63 3JW, U.K
| | - Jeff Penfold
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 OQX, U.K
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Qazi SJS, Rennie AR, Tucker I, Penfold J, Grillo I. Alignment of Dispersions of Plate-Like Colloidal Particles of Ni(OH)2Induced by Elongational Flow. J Phys Chem B 2011; 115:3271-80. [DOI: 10.1021/jp108805m] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Qazi SJS, Rennie AR, Wright JP, Cockcroft JK. Alignment of plate-like particles in a colloidal dispersion under flow in a uniform pipe studied by high-energy X-ray diffraction. Langmuir 2010; 26:18701-18709. [PMID: 21090750 DOI: 10.1021/la103537y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
High-energy angle-dispersive X-ray diffraction has been used to study the alignment of colloidal suspension of kaolinite particles in water as they flow along a pipe. X-rays with energies above 25 keV have a major advantage, as they can penetrate through thick samples and walls of containers and permit investigation of samples under realistic flow conditions. As an example of the method, flow through a circular cross-section pipe with an internal diameter of 5 mm has been studied: this is typical of industrial applications. The angular distribution of intensities of peaks in the diffraction pattern as a function of the location of the pipe in the X-ray beam provides information about the alignment of particles under flow. Order parameters have been calculated to describe the alignment and direction of orientation. It is observed that the particles align in the direction of flow with their flat faces parallel to the flow. The experimental results are compared with the calculations of the local strain rate that help to explain the onset of alignment of the particles.
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Affiliation(s)
- S Junaid S Qazi
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden.
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Qazi SJS, Karlsson G, Rennie AR. Dispersions of plate-like colloidal particles – Cubatic order? J Colloid Interface Sci 2010; 348:80-4. [DOI: 10.1016/j.jcis.2010.04.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/17/2010] [Accepted: 04/15/2010] [Indexed: 11/30/2022]
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Qazi SJS, Rennie AR, Cockcroft JK, Vickers M. Use of wide-angle X-ray diffraction to measure shape and size of dispersed colloidal particles. J Colloid Interface Sci 2009; 338:105-10. [DOI: 10.1016/j.jcis.2009.06.006] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2009] [Revised: 06/01/2009] [Accepted: 06/03/2009] [Indexed: 10/20/2022]
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