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Chouquet A, Pinto AJ, Hennicke J, Ling WL, Bally I, Schwaigerlehner L, Thielens NM, Kunert R, Reiser JB. Biophysical Characterization of the Oligomeric States of Recombinant Immunoglobulins Type-M and Their C1q-Binding Kinetics by Biolayer Interferometry. Front Bioeng Biotechnol 2022; 10:816275. [PMID: 35685087 PMCID: PMC9173649 DOI: 10.3389/fbioe.2022.816275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Immunoglobulins type-M (IgMs) are one of the first antibody classes mobilized during immune responses against pathogens and tumor cells. Binding to specific target antigens enables the interaction with the C1 complex which strongly activates the classical complement pathway. This biological function is the basis for the huge therapeutic potential of IgMs. But, due to their high oligomeric complexity, in vitro production, biochemical characterization, and biophysical characterization are challenging. In this study, we present recombinant production of two IgM models (IgM617 and IgM012) in pentameric and hexameric states and the evaluation of their polymer distribution using different biophysical methods (analytical ultracentrifugation, size exclusion chromatography coupled to multi-angle laser light scattering, mass photometry, and transmission electron microscopy). Each IgM construct is defined by a specific expression and purification pattern with different sample quality. Nevertheless, both purified IgMs were able to activate complement in a C1q-dependent manner. More importantly, BioLayer Interferometry (BLI) was used for characterizing the kinetics of C1q binding to recombinant IgMs. We show that recombinant IgMs possess similar C1q-binding properties as IgMs purified from human plasma.
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Affiliation(s)
- Anne Chouquet
- Institut de Biologie Structurale, UMR 5075, Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Andrea J Pinto
- Institut de Biologie Structurale, UMR 5075, Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Julia Hennicke
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Wai Li Ling
- Institut de Biologie Structurale, UMR 5075, Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Isabelle Bally
- Institut de Biologie Structurale, UMR 5075, Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Linda Schwaigerlehner
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Nicole M Thielens
- Institut de Biologie Structurale, UMR 5075, Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Renate Kunert
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Jean-Baptiste Reiser
- Institut de Biologie Structurale, UMR 5075, Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
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Structural insights into the catalytic cycle of a bacterial multidrug ABC efflux pump. J Mol Biol 2022; 434:167541. [DOI: 10.1016/j.jmb.2022.167541] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 12/19/2022]
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Breyton C, Javed W, Vermot A, Arnaud CA, Hajjar C, Dupuy J, Petit-Hartlein I, Le Roy A, Martel A, Thépaut M, Orelle C, Jault JM, Fieschi F, Porcar L, Ebel C. Assemblies of lauryl maltose neopentyl glycol (LMNG) and LMNG-solubilized membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:939-957. [PMID: 30776334 DOI: 10.1016/j.bbamem.2019.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 02/08/2019] [Accepted: 02/08/2019] [Indexed: 12/11/2022]
Abstract
Laurylmaltose neopentylglycol (LMNG) bears two linked hydrophobic chains of equal length and two hydrophilic maltoside groups. It arouses a strong interest in the field of membrane protein biochemistry, since it was shown to efficiently solubilize and stabilize membrane proteins often better than the commonly used dodecylmaltopyranoside (DDM), and to allow structure determination of some challenging membrane proteins. However, LMNG was described to form large micelles, which could be unfavorable for structural purposes. We thus investigated its auto-assemblies and the association state of different membrane proteins solubilized in LMNG by analytical ultracentrifugation, size exclusion chromatography coupled to light scattering, centrifugation on sucrose gradient and/or small angle scattering. At high concentrations (in the mM range), LMNG forms long rods, and it stabilized the membrane proteins investigated herein, i.e. a bacterial multidrug transporter, BmrA; a prokaryotic analogous of the eukaryotic NADPH oxidases, SpNOX; an E. coli outer membrane transporter, FhuA; and the halobacterial bacteriorhodopsin, bR. BmrA, in the Apo and the vanadate-inhibited forms showed reduced kinetics of limited proteolysis in LMNG compared to DDM. Both SpNOX and BmrA display an increased specific activity in LMNG compared to DDM. The four proteins form LMNG complexes with their usual quaternary structure and with usual amount of bound detergent. No heterogeneous complexes related to the large micelle size of LMNG alone were observed. In conditions where LMNG forms assemblies of large size, FhuA crystals diffracting to 4.0 Å were obtained by vapor diffusion. LMNG large micelle size thus does not preclude membrane protein homogeneity and crystallization.
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Affiliation(s)
- Cécile Breyton
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Waqas Javed
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France; University of Lyon, CNRS, UMR5086, Molecular Microbiology and Structural Biochemistry, IBCP, Lyon 69367, France
| | - Annelise Vermot
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Charles-Adrien Arnaud
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Christine Hajjar
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Jérôme Dupuy
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Isabelle Petit-Hartlein
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Aline Le Roy
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Anne Martel
- Institut Max Von Laue Paul Langevin, 38042 Grenoble, France
| | - Michel Thépaut
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Cédric Orelle
- University of Lyon, CNRS, UMR5086, Molecular Microbiology and Structural Biochemistry, IBCP, Lyon 69367, France
| | - Jean-Michel Jault
- University of Lyon, CNRS, UMR5086, Molecular Microbiology and Structural Biochemistry, IBCP, Lyon 69367, France
| | - Franck Fieschi
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France
| | - Lionel Porcar
- Institut Max Von Laue Paul Langevin, 38042 Grenoble, France
| | - Christine Ebel
- Univ. Grenoble Alpes, CNRS, CEA, Institute for Structural Biology (IBS), 38000 Grenoble, France.
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Probing the conformation of FhaC with small-angle neutron scattering and molecular modeling. Biophys J 2015; 107:185-96. [PMID: 24988353 DOI: 10.1016/j.bpj.2014.05.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 04/20/2014] [Accepted: 05/05/2014] [Indexed: 11/22/2022] Open
Abstract
Probing the solution structure of membrane proteins represents a formidable challenge, particularly when using small-angle scattering. Detergent molecules often present residual scattering contributions even at their match point in small-angle neutron scattering (SANS) measurements. Here, we studied the conformation of FhaC, the outer-membrane, β-barrel transporter of the Bordetella pertussis filamentous hemagglutinin adhesin. SANS measurements were performed on homogeneous solutions of FhaC solubilized in n-octyl-d17-βD-glucoside and on a variant devoid of the α helix H1, which critically obstructs the FhaC pore, in two solvent conditions corresponding to the match points of the protein and the detergent, respectively. Protein-bound detergent amounted to 142 ± 10 mol/mol as determined by analytical ultracentrifugation. By using molecular modeling and starting from three distinct conformations of FhaC and its variant embedded in lipid bilayers, we generated ensembles of protein-detergent arrangement models with 120-160 detergent molecules. The scattered curves were back-calculated for each model and compared with experimental data. Good fits were obtained for relatively compact, connected detergent belts, which occasionally displayed small detergent-free patches on the outer surface of the β barrel. The combination of SANS and modeling clearly enabled us to infer the solution structure of FhaC, with H1 inside the pore as in the crystal structure. We believe that our strategy of combining explicit atomic detergent modeling with SANS measurements has significant potential for structural studies of other detergent-solubilized membrane proteins.
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Sverzhinsky A, Chung JW, Deme JC, Fabre L, Levey KT, Plesa M, Carter DM, Lypaczewski P, Coulton JW. Membrane Protein Complex ExbB4-ExbD1-TonB1 from Escherichia coli Demonstrates Conformational Plasticity. J Bacteriol 2015; 197:1873-85. [PMID: 25802296 PMCID: PMC4420915 DOI: 10.1128/jb.00069-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/13/2015] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Iron acquisition at the outer membrane (OM) of Gram-negative bacteria is powered by the proton motive force (PMF) of the cytoplasmic membrane (CM), harnessed by the CM-embedded complex of ExbB, ExbD, and TonB. Its stoichiometry, ensemble structural features, and mechanism of action are unknown. By panning combinatorial phage libraries, periplasmic regions of dimerization between ExbD and TonB were predicted. Using overexpression of full-length His6-tagged exbB-exbD and S-tagged tonB, we purified detergent-solubilized complexes of ExbB-ExbD-TonB from Escherichia coli. Protein-detergent complexes of ∼230 kDa with a hydrodynamic radius of ∼6.0 nm were similar to previously purified ExbB₄-ExbD₂ complexes. Significantly, they differed in electronegativity by native agarose gel electrophoresis. The stoichiometry was determined to be ExbB₄-ExbD₁-TonB₁. Single-particle electron microscopy agrees with this stoichiometry. Two-dimensional averaging supported the phage display predictions, showing two forms of ExbD-TonB periplasmic heterodimerization: extensive and distal. Three-dimensional (3D) particle classification showed three representative conformations of ExbB₄-ExbD₁-TonB₁. Based on our structural data, we propose a model in which ExbD shuttles a proton across the CM via an ExbB interprotein rearrangement. Proton translocation would be coupled to ExbD-mediated collapse of extended TonB in complex with ligand-loaded receptors in the OM, followed by repositioning of TonB through extensive dimerization with ExbD. Here we present the first report for purification of the ExbB-ExbD-TonB complex, molar ratios within the complex (4:1:1), and structural biology that provides insights into 3D organization. IMPORTANCE Receptors in the OM of Gram-negative bacteria allow entry of iron-bound siderophores that are necessary for pathogenicity. Numerous iron-acquisition strategies rely upon a ubiquitous and unique protein for energization: TonB. Complexed with ExbB and ExbD, the Ton system links the PMF to OM transport. Blocking iron uptake by targeting a vital nanomachine holds promise in therapeutics. Despite much research, the stoichiometry, structural arrangement, and molecular mechanism of the CM-embedded ExbB-ExbD-TonB complex remain unreported. Here we demonstrate in vitro evidence of ExbB₄-ExbD₁-TonB₁ complexes. Using 3D EM, we reconstructed the complex in three conformational states that show variable ExbD-TonB heterodimerization. Our structural observations form the basis of a model for TonB-mediated iron acquisition.
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Affiliation(s)
| | - Jacqueline W Chung
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Justin C Deme
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Lucien Fabre
- Department of Anatomy and Cell Biology, McGill University, Montreal, QC, Canada
| | - Kristian T Levey
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Maria Plesa
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - David M Carter
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Patrick Lypaczewski
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - James W Coulton
- Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada Microbiome and Disease Tolerance Centre, McGill University, Montreal, QC, Canada
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Sverzhinsky A, Qian S, Yang L, Allaire M, Moraes I, Ma D, Chung JW, Zoonens M, Popot JL, Coulton JW. Amphipol-Trapped ExbB–ExbD Membrane Protein Complex from Escherichia coli: A Biochemical and Structural Case Study. J Membr Biol 2014; 247:1005-18. [DOI: 10.1007/s00232-014-9678-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/09/2014] [Indexed: 01/02/2023]
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