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Clifton LA, Johnson CL, Solovyova AS, Callow P, Weiss KL, Ridley H, Le Brun AP, Kinane CJ, Webster JRP, Holt SA, Lakey JH. Low resolution structure and dynamics of a colicin-receptor complex determined by neutron scattering. J Biol Chem 2011; 287:337-346. [PMID: 22081604 PMCID: PMC3249085 DOI: 10.1074/jbc.m111.302901] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Proteins that translocate across cell membranes need to overcome a significant hydrophobic barrier. This is usually accomplished via specialized protein complexes, which provide a polar transmembrane pore. Exceptions to this include bacterial toxins, which insert into and cross the lipid bilayer itself. We are studying the mechanism by which large antibacterial proteins enter Escherichia coli via specific outer membrane proteins. Here we describe the use of neutron scattering to investigate the interaction of colicin N with its outer membrane receptor protein OmpF. The positions of lipids, colicin N, and OmpF were separately resolved within complex structures by the use of selective deuteration. Neutron reflectivity showed, in real time, that OmpF mediates the insertion of colicin N into lipid monolayers. This data were complemented by Brewster Angle Microscopy images, which showed a lateral association of OmpF in the presence of colicin N. Small angle neutron scattering experiments then defined the three-dimensional structure of the colicin N-OmpF complex. This revealed that colicin N unfolds and binds to the OmpF-lipid interface. The implications of this unfolding step for colicin translocation across membranes are discussed.
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Affiliation(s)
- Luke A Clifton
- ISIS Spallation Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Christopher L Johnson
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Framlington Place, Newcastle-upon-Tyne NE2 4HH, United Kingdom
| | - Alexandra S Solovyova
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Framlington Place, Newcastle-upon-Tyne NE2 4HH, United Kingdom
| | - Phil Callow
- Partnership for Structural Biology, Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France
| | - Kevin L Weiss
- Center for Structural Molecular Biology, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
| | - Helen Ridley
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Framlington Place, Newcastle-upon-Tyne NE2 4HH, United Kingdom
| | - Anton P Le Brun
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Framlington Place, Newcastle-upon-Tyne NE2 4HH, United Kingdom
| | - Christian J Kinane
- ISIS Spallation Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - John R P Webster
- ISIS Spallation Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Stephen A Holt
- ISIS Spallation Neutron Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, United Kingdom
| | - Jeremy H Lakey
- Institute for Cell and Molecular Biosciences, The Medical School, University of Newcastle, Framlington Place, Newcastle-upon-Tyne NE2 4HH, United Kingdom.
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Watanabe Y, Inoko Y. Further application of size-exclusion chromatography combined with small-angle X-ray scattering optics for characterization of biological macromolecules. Anal Bioanal Chem 2010; 399:1449-53. [PMID: 20811739 DOI: 10.1007/s00216-010-4140-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 08/16/2010] [Accepted: 08/17/2010] [Indexed: 11/26/2022]
Abstract
Size-exclusion chromatography (gel filtration chromatography or gel permeation chromatography) in conjunction with online synchrotron radiation solution small-angle X-ray scattering optics, absorbance, and/or refractive index detectors was further assessed by application of biological macromolecules, such as the hollow sphere protein complex, apoferritin, and a linear polysaccharide, pullulan. The net X-ray scattering patterns of the eluted 24-mer molecule of apoferritin showed the specific character for the hollow spherical shape. The chromatographic (time-resolved) X-ray scattering data of the linear polysaccharide pullulan revealed the flexible chain structure during the chromatographic separation in an aqueous solution. These further applications demonstrated that the present measurement technique will be useful for not only the determination of the radius of gyration value of less than about 10 nm and molecular weight below several hundred thousand but also for the structural characterization of the various macromolecules during the chromatography.
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Affiliation(s)
- Yasushi Watanabe
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
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4
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Watanabe Y, Inoko Y. Size-exclusion chromatography combined with small-angle X-ray scattering optics. J Chromatogr A 2009; 1216:7461-5. [PMID: 19269643 DOI: 10.1016/j.chroma.2009.02.053] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 02/18/2009] [Accepted: 02/19/2009] [Indexed: 11/25/2022]
Abstract
Size-exclusion chromatography with on-line synchrotron radiation solution small-angle X-ray scattering optics, absorbance and/or refractive index detectors was evaluated by protein characterizations. The radius of gyration value and zero-angle scattering intensity of protein molecules eluted from the chromatography column were estimated using this measurement system. In addition, the characterization of the conformation of the eluted proteins was demonstrated for hen egg lysozyme and bovine submaxillary mucin. The present technique will be useful for not only the determination of the radius of gyration value and molecular weight of proteins with dimensions of 1-10 nm, but also for the structural characterization of the macromolecules during the chromatography.
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Affiliation(s)
- Yasushi Watanabe
- National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
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5
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Reassembly of an integral oligomeric membrane protein OmpF porin in n-octyl beta-D: -glucopyranoside-lipids mixtures. Protein J 2009; 28:66-73. [PMID: 19199013 DOI: 10.1007/s10930-009-9165-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The denatured monomers of an integral membrane protein OmpF porin were refolded and reassembled into its sodium dodecyl sulfate-resistant trimer in mixtures of n-octyl beta-D: -glucopyranoside and lipids. Effective reassembly was observed with a yield of 60-70% when the denatured monomers (0.1 mg/mL) were solubilized at 25 degrees C for 24 h in a refolding medium (pH 6.9) containing 7 mg/mL n-octyl beta-D: -glucopyranoside, 1 mg/mL sodium dodecyl sulfate and 2-2.5 mg/mL soybean asolectin. The reassembled species was characterized in the presence of sodium dodecyl sulfate by physicochemical methods. Low-angle laser light scattering measurements revealed that the molecular weight of the reassembled species is 115,000 +/- 3,500 which corresponds to that of the trimer of this protein. Circular dichroism spectra suggested that the reassembled species is composed of the same beta-structure as the native one. Synchrotron radiation small-angle X-ray scattering measurements confirmed that the reassembled species is a trimer that has the same compactness as the native one.
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6
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Burgess NK, Stanley AM, Fleming KG. Determination of membrane protein molecular weights and association equilibrium constants using sedimentation equilibrium and sedimentation velocity. Methods Cell Biol 2008; 84:181-211. [PMID: 17964932 DOI: 10.1016/s0091-679x(07)84007-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Regulated molecular interactions are essential for cellular function and viability, and both homo- and hetero-interactions between all types of biomolecules play important cellular roles. This chapter focuses on interactions between membrane proteins. Knowing both the stoichiometries and stabilities of these interactions in hydrophobic environments is a prerequisite for understanding how this class of proteins regulates cellular activities in membranes. Using examples from the authors' work, this chapter highlights the application of analytical ultracentrifugation methods in the determination of these parameters for integral membrane proteins. Both theoretical and practical aspects of carrying out these experiments are discussed.
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Affiliation(s)
- Nancy K Burgess
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, Maryland 21218, USA
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7
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Visudtiphole V, Thomas M, Chalton D, Lakey J. Refolding of Escherichia coli outer membrane protein F in detergent creates LPS-free trimers and asymmetric dimers. Biochem J 2005; 392:375-81. [PMID: 16153185 PMCID: PMC1316273 DOI: 10.1042/bj20051257] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Revised: 09/07/2005] [Accepted: 09/12/2005] [Indexed: 11/17/2022]
Abstract
The Escherichia coli OmpF (outer-membrane protein F; matrix porin) is a homotrimeric beta-barrel and a member of the bacterial porin superfamily. It is the best characterized porin protein, but has resisted attempts to refold it efficiently in vitro. In the present paper, we report the discovery of detergent-based folding conditions, including dodecylglucoside, which can create pure samples of trimeric OmpF. Whereas outer membrane LPS (lipopolysaccharide) is clearly required for in vivo folding, the artificially refolded and LPS-free trimer has properties identical with those of the outer-membrane-derived form. Thus LPS is not required either for in vitro folding or for structural integrity. Dimeric forms of OmpF have been observed in vivo and are proposed to be folding intermediates. In vitro, dimers occur transiently in refolding of trimeric OmpF and, in the presence of dodecylmaltoside, pure dimer can be prepared. This form has less beta-structure by CD and shows lower thermal stability than the trimer. Study of these proteins at the single-molecule level is possible because each OmpF subunit forms a distinct ion channel. Whereas each trimer contains three channels of equal conductance, each dimer always contains two distinct channel sizes. This provides clear evidence that the two otherwise identical monomers adopt different structures in the dimer and indicates that the asymmetric interaction, characteristic of C3 symmetry, is formed at the dimer stage. This asymmetric dimer may be generally relevant to the folding of oligomeric proteins with odd numbers of subunits such as aspartate transcarbamoylase.
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Key Words
- folding
- ion channel
- lipopolysaccharide
- oligomer
- outer-membrane protein f (ompf)
- single-molecule technique
- aebsf, 4-(2-aminoethyl)benzenesulphonyl fluoride
- blm, bilayer lipid membrane
- dg, n-dodecyl-β-d-glucopyranoside
- dm, n-dodecyl-β-d-maltoside
- dsc, differential scanning calorimetry
- dtt, dithiothreitol
- lps, lipopolysaccharide
- octyl-poe, n-octyl-oligo-oxyethylene
- og, n-octyl-β-d-glucopyranoside
- omp, outer membrane protein
- vapp, applied transmembrane voltage
- z, zwittergent
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Affiliation(s)
- Virak Visudtiphole
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Newcastle NE1 7RU, U.K
| | - Matthew B. Thomas
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Newcastle NE1 7RU, U.K
| | - David A. Chalton
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Newcastle NE1 7RU, U.K
| | - Jeremy H. Lakey
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Newcastle NE1 7RU, U.K
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