1
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Kermani AA. Applications of fluorescent protein tagging in structural studies of membrane proteins. FEBS J 2024; 291:2719-2732. [PMID: 37470714 DOI: 10.1111/febs.16910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/16/2023] [Accepted: 07/19/2023] [Indexed: 07/21/2023]
Abstract
Generating active, pure, and monodisperse protein remains a major bottleneck for structural studies using X-ray crystallography and cryo-electron microscopy (cryo-EM). The current methodology heavily relies on overexpressing the recombinant protein fused with a histidine tag in conventional expression systems and evaluating the quality and stability of purified protein using size exclusion chromatography (SEC). This requires a large amount of protein and can be highly laborious and time consuming. Therefore, this approach is not suitable for high-throughput screening and low-expressing macromolecules, particularly eukaryotic membrane proteins. Using fluorescent proteins fused to the target protein (applicable to both soluble and membrane proteins) enables rapid and efficient screening of expression level and monodispersity of tens of unpurified constructs using fluorescence-based size exclusion chromatography (FSEC). Moreover, FSEC proves valuable for screening multiple detergents to identify the most stabilizing agent in the case of membrane proteins. Additionally, FSEC can facilitate nanodisc reconstitution by determining the optimal ratio of membrane scaffold protein (MSP), lipids, and target protein. The distinct advantages offered by FSEC indicate that fluorescent proteins can serve as a viable alternative to commonly used affinity tags for both characterization and purification purposes. In this review, I will summarize the advantages of this technique using examples from my own work. It should be noted that this article is not intended to provide an exhaustive review of all available literature, but rather to offer representative examples of FSEC applications.
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Affiliation(s)
- Ali A Kermani
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
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2
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Castaño JD, El Khoury IV, Goering J, Evans JE, Zhang J. Unlocking the distinctive enzymatic functions of the early plant biomass deconstructive genes in a brown rot fungus by cell-free protein expression. Appl Environ Microbiol 2024; 90:e0012224. [PMID: 38567954 PMCID: PMC11205865 DOI: 10.1128/aem.00122-24] [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: 01/23/2024] [Accepted: 03/10/2024] [Indexed: 05/22/2024] Open
Abstract
Saprotrophic fungi that cause brown rot of woody biomass evolved a distinctive mechanism that relies on reactive oxygen species (ROS) to kick-start lignocellulosic polymers' deconstruction. These ROS agents are generated at incipient decay stages through a series of redox relays that shuttle electrons from fungus's central metabolism to extracellular Fenton chemistry. A list of genes has been suggested encoding the enzyme catalysts of the redox processes involved in ROS's function. However, navigating the functions of the encoded enzymes has been challenging due to the lack of a rapid method for protein synthesis. Here, we employed cell-free expression system to synthesize four redox or degradative enzymes, which were identified, by transcriptomic data, as conserved players of the ROS oxidation phase across brown rot fungal species. All four enzymes were successfully expressed and showed activities that enable confident assignment of function, namely, benzoquinone reductase (BQR), ferric reductase, α-L-arabinofuranosidase (ABF), and heme-thiolate peroxidase (HTP). Detailed analysis of their catalytic features within the context of brown rot environments allowed us to interpret their roles during ROS-driven wood decomposition. Specifically, we validated the functions of BQR as the driver redox enzyme of Fenton cycles and reconstructed its interactions with the co-occurring HTP or laccase and ABF. Taken together, this research demonstrated that the cell-free expression platform is adequate for synthesizing functional fungal enzymes and provided an alternative route for the rapid characterization of fungal proteins, escalating our understanding of the distinctive biocatalyst system for plant biomass conversion.IMPORTANCEBrown rot fungi are efficient wood decomposers in nature, and their unique degradative systems harbor untapped catalysts pursued by the biorefinery and bioremediation industries. While the use of "omics" platforms has recently uncovered the key "oxidative-hydrolytic" mechanisms that allow these fungi to attack lignocellulose, individual protein characterization is lagging behind due to the lack of a robust method for rapid synthesis of crucial fungal enzymes. This work delves into the studies of biochemical functions of brown rot enzymes using a rapid, cell-free expression platform, which allowed the successful depictions of enzymes' catalytic features, their interactions with Fenton chemistry, and their roles played during the incipient stage of brown rot when fungus sets off the reactive oxygen species for oxidative degradation. We expect this research could illuminate cell-free protein expression system's use to fulfill the increasing need for functional studies of fungal enzymes, advancing the discoveries of novel biomass-converting catalysts.
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Affiliation(s)
- Jesus D. Castaño
- Bioproducts and Biosystems Engineering, University of Minnesota, Saint Paul, Minnesota, USA
| | - Irina V. El Khoury
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
| | - Joshua Goering
- Bioproducts and Biosystems Engineering, University of Minnesota, Saint Paul, Minnesota, USA
| | - James E. Evans
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, USA
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Jiwei Zhang
- Bioproducts and Biosystems Engineering, University of Minnesota, Saint Paul, Minnesota, USA
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3
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Köck Z, Schnelle K, Persechino M, Umbach S, Schihada H, Januliene D, Parey K, Pockes S, Kolb P, Dötsch V, Möller A, Hilger D, Bernhard F. Cryo-EM structure of cell-free synthesized human histamine 2 receptor/G s complex in nanodisc environment. Nat Commun 2024; 15:1831. [PMID: 38418462 PMCID: PMC10901899 DOI: 10.1038/s41467-024-46096-z] [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: 07/13/2023] [Accepted: 02/14/2024] [Indexed: 03/01/2024] Open
Abstract
Here we describe the cryo-electron microscopy structure of the human histamine 2 receptor (H2R) in an active conformation with bound histamine and in complex with Gs heterotrimeric protein at an overall resolution of 3.4 Å. The complex was generated by cotranslational insertion of the receptor into preformed nanodisc membranes using cell-free synthesis in E. coli lysates. Structural comparison with the inactive conformation of H2R and the inactive and Gq-coupled active state of H1R together with structure-guided functional experiments reveal molecular insights into the specificity of ligand binding and G protein coupling for this receptor family. We demonstrate lipid-modulated folding of cell-free synthesized H2R, its agonist-dependent internalization and its interaction with endogenously synthesized H1R and H2R in HEK293 cells by applying a recently developed nanotransfer technique.
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Affiliation(s)
- Zoe Köck
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University of Frankfurt/Main, Frankfurt, Germany
| | - Kilian Schnelle
- Department of Biology/Chemistry, Structural Biology section, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | | | - Simon Umbach
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University of Frankfurt/Main, Frankfurt, Germany
| | - Hannes Schihada
- Department of Pharmaceutical Chemistry, University of Marburg, Marburg, Germany
| | - Dovile Januliene
- Department of Biology/Chemistry, Structural Biology section, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Kristian Parey
- Department of Biology/Chemistry, Structural Biology section, University of Osnabrück, Osnabrück, Germany
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany
| | - Steffen Pockes
- Institute of Pharmacy, University of Regensburg, Regensburg, Germany
| | - Peter Kolb
- Department of Pharmaceutical Chemistry, University of Marburg, Marburg, Germany
| | - Volker Dötsch
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University of Frankfurt/Main, Frankfurt, Germany
| | - Arne Möller
- Department of Biology/Chemistry, Structural Biology section, University of Osnabrück, Osnabrück, Germany.
- Center of Cellular Nanoanalytic Osnabrück (CellNanOs), University of Osnabrück, Osnabrück, Germany.
| | - Daniel Hilger
- Department of Pharmaceutical Chemistry, University of Marburg, Marburg, Germany.
| | - Frank Bernhard
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University of Frankfurt/Main, Frankfurt, Germany.
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Levesque I, Juliano BR, Parson KF, Ruotolo BT. A Critical Evaluation of Detergent Exchange Methodologies for Membrane Protein Native Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2662-2671. [PMID: 37956121 DOI: 10.1021/jasms.3c00230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Membrane proteins (MPs) play many critical roles in cellular physiology and constitute the majority of current pharmaceutical targets. However, MPs are comparatively understudied relative to soluble proteins due to the challenges associated with their solubilization in membrane mimetics. Native mass spectrometry (nMS) has emerged as a useful technique to probe the structures of MPs. Typically, nMS studies using MPs have employed detergent micelles to solubilize the MP. Oftentimes, the detergent micelle that the MP was purified in will be exchanged into another detergent prior to analysis by nMS. While methodologies for performing detergent exchange have been extensively described in prior reports, the effectiveness of these protocols remains understudied. Here, we present a critical analysis of detergent exchange efficacy using several model transmembrane proteins and a variety of commonly used detergents, evaluating the completeness of the exchange using a battery of existing protocols. Our data include results for octyl glucoside (OG), octaethylene glycol monododecyl ether (C12E8), and tetraethylene glycol monooctyl ether (C8E4), and these data demonstrate that existing protocols are insufficient and yield incomplete exchange for the proteins under the conditions probed here. In some cases, our data indicate that up to 99% of the measured detergent corresponds to the original pre-exchange detergent rather than the desired post-exchange detergent. We conclude by discussing the need for new detergent exchange methodologies alongside improved exchange yield expectations for studying the potential influence of detergents on MP structures.
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Affiliation(s)
- Iliana Levesque
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brock R Juliano
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kristine F Parson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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5
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Lupu L, Kleinekofort W, Morgner N. Epitope characterization of proteins and aptamers with mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2023; 29:359-369. [PMID: 37957929 DOI: 10.1177/14690667231208530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The way in which professor Michael Przybylski has combined the spirit of research with entrepreneurship has set an example for any and all scientists. He has made significant achievements in the fields of mass spectrometry, biochemistry and medicine, and has initiated important technological developments in the area of protein analysis. Between 2016 and 2023 professor Przybylski's scientific focus shifted on protein interactions with emphasis on aptamer-protein and antibody-protein analysis. This review focuses on professor Przybylski's achievements in the last few years highlighting his impact on the scientific community, on his students and colleagues.
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Affiliation(s)
- Loredana Lupu
- AffyMSLifeChem Centre for Analytical Biochemistry and Biomedical Mass Spectrometry, Rüsselsheim am Main, Germany
| | | | - Nina Morgner
- Institut für Physikalische und Theoretische Chemie, Goethe-Universität Frankfurt am Main, Frankfurt Am Main, Germany
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6
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Mezhyrova J, Martin J, Börnsen C, Dötsch V, Frangakis AS, Morgner N, Bernhard F. In vitro characterization of the phage lysis protein MS2-L. MICROBIOME RESEARCH REPORTS 2023; 2:28. [PMID: 38045926 PMCID: PMC10688784 DOI: 10.20517/mrr.2023.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/29/2023] [Accepted: 07/10/2023] [Indexed: 12/05/2023]
Abstract
Background: The peptide MS2-L represents toxins of the ssRNA Leviviridae phage family and consists of a predicted N-terminal soluble domain followed by a transmembrane domain. MS2-L mediates bacterial cell lysis through the formation of large lesions in the cell envelope, but further details of this mechanism as a prerequisite for applied bioengineering studies are lacking. The chaperone DnaJ is proposed to modulate MS2-L activity, whereas other cellular targets of MS2-L are unknown. Methods: Here, we provide a combined in vitro and in vivo overexpression approach to reveal molecular insights into MS2-L action and its interaction with DnaJ. Full-length MS2-L and truncated derivatives were synthesized cell-free and co-translationally inserted into nanodiscs or solubilized in detergent micelles. By native liquid bead ion desorption mass spectrometry, we demonstrate that MS2-L assembles into high oligomeric states after membrane insertion. Results: Oligomerization is directed by the transmembrane domain and is impaired in detergent environments. Studies with truncated MS2-L derivatives provide evidence that the soluble domain acts as a modulator of oligomer formation. DnaJ strongly interacts with MS2-L in membranes as well as in detergent environments. However, this interaction affects neither the MS2-L membrane insertion efficiency nor its oligomerization in nanodisc membranes. In accordance with the in vitro data, the assembly of MS2-L derivatives into large membrane located clusters was monitored by overexpression of corresponding fusions with fluorescent monitors in E. coli cells. Analysis by cryo-electron microscopy indicates that lesion formation is initiated in the outer membrane, followed by disruption of the peptidoglycan layer and disintegration of the inner membrane. Conclusion: MS2-L forms oligomeric complexes similar to the related phage toxin ΦX174-E. The oligomeric interface of both peptides is located within their transmembrane domains. We propose a potential function of the higher-order assembly of small phage toxins in membrane disintegration and cell lysis.
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Affiliation(s)
- Julija Mezhyrova
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main 60438, Germany
| | - Janosch Martin
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt am Main 60438, Germany
| | - Clara Börnsen
- Buchmann Institute for Molecular Life Sciences & Institute of Biophysics, Goethe University, Frankfurt am Main 60438, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main 60438, Germany
| | - Achilleas Stefanos Frangakis
- Buchmann Institute for Molecular Life Sciences & Institute of Biophysics, Goethe University, Frankfurt am Main 60438, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt am Main 60438, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main 60438, Germany
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7
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Orta AK, Riera N, Li YE, Tanaka S, Yun HG, Klaic L, Clemons WM. The mechanism of the phage-encoded protein antibiotic from ΦX174. Science 2023; 381:eadg9091. [PMID: 37440661 DOI: 10.1126/science.adg9091] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 05/23/2023] [Indexed: 07/15/2023]
Abstract
The historically important phage ΦX174 kills its host bacteria by encoding a 91-residue protein antibiotic called protein E. Using single-particle electron cryo-microscopy, we demonstrate that protein E bridges two bacterial proteins to form the transmembrane YES complex [MraY, protein E, sensitivity to lysis D (SlyD)]. Protein E inhibits peptidoglycan biosynthesis by obstructing the MraY active site leading to loss of lipid I production. We experimentally validate this result for two different viral species, providing a clear model for bacterial lysis and unifying previous experimental data. Additionally, we characterize the Escherichia coli MraY structure-revealing features of this essential enzyme-and the structure of the chaperone SlyD bound to a protein. Our structures provide insights into the mechanism of phage-mediated lysis and for structure-based design of phage therapeutics.
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Affiliation(s)
- Anna K Orta
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Nadia Riera
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yancheng E Li
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Shiho Tanaka
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Hyun Gi Yun
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lada Klaic
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - William M Clemons
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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8
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Bailoni E, Partipilo M, Coenradij J, Grundel DAJ, Slotboom DJ, Poolman B. Minimal Out-of-Equilibrium Metabolism for Synthetic Cells: A Membrane Perspective. ACS Synth Biol 2023; 12:922-946. [PMID: 37027340 PMCID: PMC10127287 DOI: 10.1021/acssynbio.3c00062] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Indexed: 04/08/2023]
Abstract
Life-like systems need to maintain a basal metabolism, which includes importing a variety of building blocks required for macromolecule synthesis, exporting dead-end products, and recycling cofactors and metabolic intermediates, while maintaining steady internal physical and chemical conditions (physicochemical homeostasis). A compartment, such as a unilamellar vesicle, functionalized with membrane-embedded transport proteins and metabolic enzymes encapsulated in the lumen meets these requirements. Here, we identify four modules designed for a minimal metabolism in a synthetic cell with a lipid bilayer boundary: energy provision and conversion, physicochemical homeostasis, metabolite transport, and membrane expansion. We review design strategies that can be used to fulfill these functions with a focus on the lipid and membrane protein composition of a cell. We compare our bottom-up design with the equivalent essential modules of JCVI-syn3a, a top-down genome-minimized living cell with a size comparable to that of large unilamellar vesicles. Finally, we discuss the bottlenecks related to the insertion of a complex mixture of membrane proteins into lipid bilayers and provide a semiquantitative estimate of the relative surface area and lipid-to-protein mass ratios (i.e., the minimal number of membrane proteins) that are required for the construction of a synthetic cell.
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Affiliation(s)
- Eleonora Bailoni
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Michele Partipilo
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Jelmer Coenradij
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Douwe A. J. Grundel
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Dirk J. Slotboom
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- Department
of Biochemistry and Molecular Systems Biology, Groningen Biomolecular
Sciences and Biotechnology Institute, University
of Groningen, Nijenborgh
4, 9747 AG Groningen, The Netherlands
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9
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Nishiguchi R, Tanaka T, Hayashida J, Nakagita T, Zhou W, Takeda H. Evaluation of Cell-Free Synthesized Human Channel Proteins for In Vitro Channel Research. MEMBRANES 2022; 13:48. [PMID: 36676855 PMCID: PMC9861611 DOI: 10.3390/membranes13010048] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Despite channel proteins being important drug targets, studies on channel proteins remain limited, as the proteins are difficult to express and require correct complex formation within membranes. Although several in vitro synthesized recombinant channels have been reported, considering the vast diversity of the structures and functions of channel proteins, it remains unclear which classes of channels cell-free synthesis can be applied to. In this study, we synthesized 250 clones of human channels, including ion channel pore-forming subunits, gap junction proteins, porins, and regulatory subunits, using a wheat cell-free membrane protein production system, and evaluated their synthetic efficiency and function. Western blotting confirmed that 95% of the channels were successfully synthesized, including very large channels with molecular weights of over 200 kDa. A subset of 47 voltage-gated potassium ion channels was further analyzed using a planar lipid bilayer assay, out of which 80% displayed a voltage-dependent opening in the assay. We co-synthesized KCNB1 and KCNS3, a known heteromeric complex pair, and demonstrated that these channels interact on a liposome. These results indicate that cell-free protein synthesis provides a promising solution for channel studies to overcome the bottleneck of in vitro protein production.
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Affiliation(s)
- Rei Nishiguchi
- Proteo-Science Center, Ehime University, Bunkyocho 3, Matsuyama 790-8577, Ehime, Japan
| | - Toyohisa Tanaka
- Proteo-Science Center, Ehime University, Bunkyocho 3, Matsuyama 790-8577, Ehime, Japan
| | - Jun Hayashida
- Nissan Chemical Corporation, Shiraoka 1470, Shiraoka 349-0294, Saitama, Japan
| | - Tomoya Nakagita
- Proteo-Science Center, Ehime University, Bunkyocho 3, Matsuyama 790-8577, Ehime, Japan
| | - Wei Zhou
- Proteo-Science Center, Ehime University, Bunkyocho 3, Matsuyama 790-8577, Ehime, Japan
| | - Hiroyuki Takeda
- Proteo-Science Center, Ehime University, Bunkyocho 3, Matsuyama 790-8577, Ehime, Japan
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Glueck D, Grethen A, Das M, Mmeka OP, Patallo EP, Meister A, Rajender R, Kins S, Räschle M, Victor J, Chu C, Etzkorn M, Köck Z, Bernhard F, Babalola JO, Vargas C, Keller S. Electroneutral Polymer Nanodiscs Enable Interference-Free Probing of Membrane Proteins in a Lipid-Bilayer Environment. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202492. [PMID: 36228092 DOI: 10.1002/smll.202202492] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 09/10/2022] [Indexed: 06/16/2023]
Abstract
Membrane proteins can be examined in near-native lipid-bilayer environments with the advent of polymer-encapsulated nanodiscs. These nanodiscs self-assemble directly from cellular membranes, allowing in vitro probing of membrane proteins with techniques that have previously been restricted to soluble or detergent-solubilized proteins. Often, however, the high charge densities of existing polymers obstruct bioanalytical and preparative techniques. Thus, the authors aim to fabricate electroneutral-yet water-soluble-polymer nanodiscs. By attaching a sulfobetaine group to the commercial polymers DIBMA and SMA(2:1), these polyanionic polymers are converted to the electroneutral maleimide derivatives, Sulfo-DIBMA and Sulfo-SMA(2:1). Sulfo-DIBMA and Sulfo-SMA(2:1) readily extract proteins and phospholipids from artificial and cellular membranes to form nanodiscs. Crucially, the electroneutral nanodiscs avert unspecific interactions, thereby enabling new insights into protein-lipid interactions through lab-on-a-chip detection and in vitro translation of membrane proteins. Finally, the authors create a library comprising thousands of human membrane proteins and use proteome profiling by mass spectrometry to show that protein complexes are preserved in electroneutral nanodiscs.
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Affiliation(s)
- David Glueck
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, Graz, 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Anne Grethen
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Manabendra Das
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Ogochukwu Patricia Mmeka
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
- Department of Chemistry, University of Ibadan, Ibadan, 200284, Nigeria
| | - Eugenio Pérez Patallo
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Annette Meister
- HALOmem and Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany
| | - Ritu Rajender
- Human Biology, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Stefan Kins
- Human Biology, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - Markus Räschle
- Molecular Genetics, Technische Universität Kaiserslautern (TUK), Paul-Ehrlich-Str. 24, 67663, Kaiserslautern, Germany
| | - Julian Victor
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Ci Chu
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Manuel Etzkorn
- Institut für Physikalische Biologie, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225, Düsseldorf, Germany
| | - Zoe Köck
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University of Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany
| | - Frank Bernhard
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University of Frankfurt/Main, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany
| | | | - Carolyn Vargas
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, Graz, 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Sandro Keller
- Molecular Biophysics, Technische Universität Kaiserslautern (TUK), Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
- Biophysics, Institute of Molecular Biosciences (IMB), NAWI Graz, University of Graz, Humboldtstr. 50/III, Graz, 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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11
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Levin R, Köck Z, Martin J, Zangl R, Gewering T, Schüler L, Moeller A, Dötsch V, Morgner N, Bernhard F. Cotranslational assembly of membrane protein/nanoparticles in cell-free systems. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184017. [PMID: 35921875 DOI: 10.1016/j.bbamem.2022.184017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/18/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Nanoparticles composed of amphiphilic scaffold proteins and small lipid bilayers are valuable tools for reconstitution and subsequent functional and structural characterization of membrane proteins. In combination with cell-free protein production systems, nanoparticles can be used to cotranslationally and translocon independently insert membrane proteins into tailored lipid environments. This strategy enables rapid generation of protein/nanoparticle complexes by avoiding detergent contact of nascent membrane proteins. Frequently in use are nanoparticles assembled with engineered derivatives of either the membrane scaffold protein (MSP) or the Saposin A (SapA) scaffold. Furthermore, several strategies for the formation of membrane protein/nanoparticle complexes in cell-free reactions exist. However, it is unknown how these strategies affect functional folding, oligomeric assembly and membrane insertion efficiency of cell-free synthesized membrane proteins. We systematically studied membrane protein insertion efficiency and sample quality of cell-free synthesized proteorhodopsin (PR) which was cotranslationally inserted in MSP and SapA based nanoparticles. Three possible PR/nanoparticle formation strategies were analyzed: (i) PR integration into supplied preassembled nanoparticles, (ii) coassembly of nanoparticles from supplied scaffold proteins and lipids upon PR expression, and (iii) coexpression of scaffold proteins together with PR in presence of supplied lipids. Yield, homogeneity as well as the formation of higher PR oligomeric complexes from samples generated by the three strategies were analyzed. Conditions found optimal for PR were applied for the synthesis of a G-protein coupled receptor. The study gives a comprehensive guideline for the rapid synthesis of membrane protein/nanoparticle samples by different processes and identifies key parameters to modulate sample yield and quality.
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Affiliation(s)
- Roman Levin
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Zoe Köck
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Janosch Martin
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany
| | - René Zangl
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany
| | | | - Leah Schüler
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Arne Moeller
- University of Osnabrück, 49076 Osnabrück, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, Goethe University, 60438 Frankfurt, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, 60438 Frankfurt, Germany.
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12
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Korn P, Schwieger C, Gruhle K, Garamus VM, Meister A, Ihling C, Drescher S. Azide- and diazirine-modified membrane lipids: Physicochemistry and applicability to study peptide/lipid interactions via cross-linking/mass spectrometry. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184004. [PMID: 35841926 DOI: 10.1016/j.bbamem.2022.184004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Although the incorporation of photo-activatable lipids into membranes potentially opens new avenues for studying interactions with peptides and proteins, the question of whether azide- or diazirine-modified lipids are suitable for such studies remains controversial. We have recently shown that diazirine-modified lipids can indeed form cross-links to membrane peptides after UV activation and that these cross-links can be precisely determined in their position by mass spectrometry (MS). However, we also observed an unexpected backfolding of the lipid's diazirine-containing stearoyl chain to the membrane interface challenging the potential application of this modified lipid for future cross-linking (XL)-MS studies of protein/lipid interactions. In this work, we compared an azide- (AzidoPC) and a diazirine-modified (DiazPC) membrane lipid regarding their self-assembly properties, their mixing behavior with saturated bilayer-forming phospholipids, and their reactivity upon UV activation using differential scanning calorimetry (DSC), dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and MS. Mixtures of both modified lipids with DMPC were further used for photo-chemically induced XL experiments with a transmembrane model peptide (KLAW23) to elucidate similarities and differences between the azide and the diazirine moiety. We showed that both photo-reactive lipids can be used to study lipid/peptide and lipid/protein interactions. The AzidoPC proved easier to handle, whereas the DiazPC had fewer degradation products and a higher cross-linking yield. However, the problem of backfolding occurs in both lipids; thus, it seems to be a general phenomenon.
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Affiliation(s)
- Patricia Korn
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Charles Tanford Protein Center, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle (Saale), Germany
| | - Christian Schwieger
- Institute of Chemistry, MLU Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle (Saale), Germany
| | - Kai Gruhle
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Charles Tanford Protein Center, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle (Saale), Germany; Institute of Pharmacy-Biophysical Pharmacy, MLU Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany
| | - Vasil M Garamus
- Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Annette Meister
- Interdisciplinary Research Center HALOmem, MLU Halle-Wittenberg, Charles Tanford Protein Center, Kurt-Mothes-Str. 3a, 06120 Halle (Saale), Germany; Institute of Biochemistry and Biotechnology-Physical Biotechnology, Charles Tanford Protein Center, MLU Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle (Saale), Germany
| | - Christian Ihling
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Charles Tanford Protein Center, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120 Halle (Saale), Germany; Center for Structural Mass Spectrometry, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Simon Drescher
- Institute of Pharmacy-Biophysical Pharmacy, MLU Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120 Halle (Saale), Germany; Phospholipid Research Center, Im Neuenheimer Feld 515, 69120 Heidelberg, Germany.
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13
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Umbach S, Levin R, Neumann S, Steinmetzer T, Dötsch V, Bernhard F. Transfer mechanism of cell-free synthesized membrane proteins into mammalian cells. Front Bioeng Biotechnol 2022; 10:906295. [PMID: 35935506 PMCID: PMC9355040 DOI: 10.3389/fbioe.2022.906295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/27/2022] [Indexed: 11/21/2022] Open
Abstract
Nanodiscs are emerging to serve as transfer vectors for the insertion of recombinant membrane proteins into membranes of living cells. In combination with cell-free expression technologies, this novel process opens new perspectives to analyze the effects of even problematic targets such as toxic, hard-to-express, or artificially modified membrane proteins in complex cellular environments of different cell lines. Furthermore, transferred cells must not be genetically engineered and primary cell lines or cancer cells could be implemented as well. We have systematically analyzed the basic parameters of the nanotransfer approach and compared the transfer efficiencies from nanodiscs with that from Salipro particles. The transfer of five membrane proteins was analyzed: the prokaryotic proton pump proteorhodopsin, the human class A family G-protein coupled receptors for endothelin type B, prostacyclin, free fatty acids type 2, and the orphan GPRC5B receptor as a class C family member. The membrane proteins were cell-free synthesized with a detergent-free strategy by their cotranslational insertion into preformed nanoparticles containing defined lipid environments. The purified membrane protein/nanoparticles were then incubated with mammalian cells. We demonstrate that nanodiscs disassemble and only lipids and membrane proteins, not the scaffold protein, are transferred into cell membranes. The process is detectable within minutes, independent of the nanoparticle lipid composition, and the transfer efficiency directly correlates with the membrane protein concentration in the transfer mixture and with the incubation time. Transferred membrane proteins insert in both orientations, N-terminus in and N-terminus out, in the cell membrane, and the ratio can be modulated by engineering. The viability of cells is not notably affected by the transfer procedure, and transferred membrane proteins stay detectable in the cell membrane for up to 3 days. Transferred G-protein coupled receptors retained their functionality in the cell environment as shown by ligand binding, induction of internalization, and specific protein interactions. In comparison to transfection, the cellular membrane protein concentration is better controllable and more uniformly distributed within the analyzed cell population. A further notable difference to transfection is the accumulation of transferred membrane proteins in clusters, presumably determined by microdomain structures in the cell membranes.
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Affiliation(s)
- Simon Umbach
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany
| | - Roman Levin
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany
| | - Sebastian Neumann
- Institute for Pharmaceutical Chemistry, Philipps University, Marburg, Germany
| | - Torsten Steinmetzer
- Institute for Pharmaceutical Chemistry, Philipps University, Marburg, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany
- *Correspondence: Frank Bernhard,
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14
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Harris NJ, Pellowe GA, Blackholly LR, Gulaidi-Breen S, Findlay HE, Booth PJ. Methods to study folding of alpha-helical membrane proteins in lipids. Open Biol 2022; 12:220054. [PMID: 35855589 PMCID: PMC9297032 DOI: 10.1098/rsob.220054] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
How alpha-helical membrane proteins fold correctly in the highly hydrophobic membrane interior is not well understood. Their folding is known to be highly influenced by the lipids within the surrounding bilayer, but the majority of folding studies have focused on detergent-solubilized protein rather than protein in a lipid environment. There are different ways to study folding in lipid bilayers, and each method has its own advantages and disadvantages. This review will discuss folding methods which can be used to study alpha-helical membrane proteins in bicelles, liposomes, nanodiscs or native membranes. These folding methods include in vitro folding methods in liposomes such as denaturant unfolding studies, and single-molecule force spectroscopy studies in bicelles, liposomes and native membranes. This review will also discuss recent advances in co-translational folding studies, which use cell-free expression with liposomes or nanodiscs or are performed in vivo with native membranes.
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Affiliation(s)
- Nicola J. Harris
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Grant A. Pellowe
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Laura R. Blackholly
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | | | - Heather E. Findlay
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Paula J. Booth
- Department of Chemistry, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK,The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
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15
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LILBID-MS: using lasers to shed light on biomolecular architectures. Biochem Soc Trans 2022; 50:1057-1067. [PMID: 35695670 PMCID: PMC9317959 DOI: 10.1042/bst20190881] [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: 03/08/2022] [Revised: 05/15/2022] [Accepted: 05/20/2022] [Indexed: 11/17/2022]
Abstract
Structural Biology has moved beyond the aim of simply identifying the components of a cellular subsystem towards analysing the dynamics and interactions of multiple players within a cell. This focal shift comes with additional requirements for the analytical tools used to investigate these systems of increased size and complexity, such as Native Mass Spectrometry, which has always been an important tool for structural biology. Scientific advance and recent developments, such as new ways to mimic a cell membrane for a membrane protein, have caused established methods to struggle to keep up with the increased demands. In this review, we summarize the possibilities, which Laser Induced Liquid Bead Ion Desorption (LILBID) mass spectrometry offers with regard to the challenges of modern structural biology, like increasingly complex sample composition, novel membrane mimics and advanced structural analysis, including next neighbor relations and the dynamics of complex formation.
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16
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Oluwole AO, Corey RA, Brown CM, Hernández-Rocamora VM, Stansfeld PJ, Vollmer W, Bolla JR, Robinson CV. Peptidoglycan biosynthesis is driven by lipid transfer along enzyme-substrate affinity gradients. Nat Commun 2022; 13:2278. [PMID: 35477938 PMCID: PMC9046198 DOI: 10.1038/s41467-022-29836-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 03/31/2022] [Indexed: 01/02/2023] Open
Abstract
Maintenance of bacterial cell shape and resistance to osmotic stress by the peptidoglycan (PG) renders PG biosynthetic enzymes and precursors attractive targets for combating bacterial infections. Here, by applying native mass spectrometry, we elucidate the effects of lipid substrates on the PG membrane enzymes MraY, MurG, and MurJ. We show that dimerization of MraY is coupled with binding of the carrier lipid substrate undecaprenyl phosphate (C55-P). Further, we demonstrate the use of native MS for biosynthetic reaction monitoring and find that the passage of substrates and products is controlled by the relative binding affinities of the different membrane enzymes. Overall, we provide a molecular view of how PG membrane enzymes convey lipid precursors through favourable binding events and highlight possible opportunities for intervention. Bacterial cell wall enzymes and their precursors are critical targets for antibiotic development. Here, the authors investigate several biosynthetic enzymes with their substrates and show that the passage of substrates and products in the pathway is controlled by their relative binding affinities.
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Affiliation(s)
- Abraham O Oluwole
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK.,The Kavli Institute for Nanoscience Discovery, South Parks Road, Oxford, OX1 3QU, UK
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Chelsea M Brown
- School of Life Sciences and Department of Chemistry, University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK
| | - Victor M Hernández-Rocamora
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.,School of Life Sciences and Department of Chemistry, University of Warwick, Gibbet Hill Campus, Coventry, CV4 7AL, UK
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK
| | - Jani R Bolla
- The Kavli Institute for Nanoscience Discovery, South Parks Road, Oxford, OX1 3QU, UK. .,Department of Plant Sciences/Biology, University of Oxford, Oxford, OX1 3RB, UK.
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK. .,The Kavli Institute for Nanoscience Discovery, South Parks Road, Oxford, OX1 3QU, UK.
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17
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Vallejo DD, Rojas Ramírez C, Parson KF, Han Y, Gadkari VV, Ruotolo BT. Mass Spectrometry Methods for Measuring Protein Stability. Chem Rev 2022; 122:7690-7719. [PMID: 35316030 DOI: 10.1021/acs.chemrev.1c00857] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mass spectrometry is a central technology in the life sciences, providing our most comprehensive account of the molecular inventory of the cell. In parallel with developments in mass spectrometry technologies targeting such assessments of cellular composition, mass spectrometry tools have emerged as versatile probes of biomolecular stability. In this review, we cover recent advancements in this branch of mass spectrometry that target proteins, a centrally important class of macromolecules that accounts for most biochemical functions and drug targets. Our efforts cover tools such as hydrogen-deuterium exchange, chemical cross-linking, ion mobility, collision induced unfolding, and other techniques capable of stability assessments on a proteomic scale. In addition, we focus on a range of application areas where mass spectrometry-driven protein stability measurements have made notable impacts, including studies of membrane proteins, heat shock proteins, amyloidogenic proteins, and biotherapeutics. We conclude by briefly discussing the future of this vibrant and fast-moving area of research.
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Affiliation(s)
- Daniel D Vallejo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Carolina Rojas Ramírez
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kristine F Parson
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yilin Han
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Varun V Gadkari
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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18
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Corin K, Bowie JU. How physical forces drive the process of helical membrane protein folding. EMBO Rep 2022; 23:e53025. [PMID: 35133709 PMCID: PMC8892262 DOI: 10.15252/embr.202153025] [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: 04/07/2021] [Revised: 07/17/2021] [Accepted: 11/24/2021] [Indexed: 11/09/2022] Open
Abstract
Protein folding is a fundamental process of life with important implications throughout biology. Indeed, tens of thousands of mutations have been associated with diseases, and most of these mutations are believed to affect protein folding rather than function. Correct folding is also a key element of design. These factors have motivated decades of research on protein folding. Unfortunately, knowledge of membrane protein folding lags that of soluble proteins. This gap is partly caused by the greater technical challenges associated with membrane protein studies, but also because of additional complexities. While soluble proteins fold in a homogenous water environment, membrane proteins fold in a setting that ranges from bulk water to highly charged to apolar. Thus, the forces that drive folding vary in different regions of the protein, and this complexity needs to be incorporated into our understanding of the folding process. Here, we review our understanding of membrane protein folding biophysics. Despite the greater challenge, better model systems and new experimental techniques are starting to unravel the forces and pathways in membrane protein folding.
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Affiliation(s)
- Karolina Corin
- Department of Chemistry and BiochemistryMolecular Biology InstituteUCLA‐DOE InstituteUniversity of CaliforniaLos AngelesCAUSA
| | - James U Bowie
- Department of Chemistry and BiochemistryMolecular Biology InstituteUCLA‐DOE InstituteUniversity of CaliforniaLos AngelesCAUSA
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19
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Brady R, Harris NJ, Pellowe GA, Gulaidi Breen S, Booth PJ. How lipids affect the energetics of co-translational alpha helical membrane protein folding. Biochem Soc Trans 2022; 50:555-567. [PMID: 35212365 PMCID: PMC9022994 DOI: 10.1042/bst20201063] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/08/2022] [Accepted: 02/14/2022] [Indexed: 11/23/2022]
Abstract
Membrane proteins need to fold with precision in order to function correctly, with misfolding potentially leading to disease. The proteins reside within a hydrophobic lipid membrane and must insert into the membrane and fold correctly, generally whilst they are being translated by the ribosome. Favourable and unfavourable free energy contributions are present throughout each stage of insertion and folding. The unfavourable energy cost of transferring peptide bonds into the hydrophobic membrane interior is compensated for by the favourable hydrophobic effect of partitioning a hydrophobic transmembrane alpha-helix into the membrane. Native membranes are composed of many different types of lipids, but how these different lipids influence folding and the associated free energies is not well understood. Altering the lipids in the bilayer is known to affect the probability of transmembrane helix insertion into the membrane, and lipids also affect protein stability and can promote successful folding. This review will summarise the free energy contributions associated with insertion and folding of alpha helical membrane proteins, as well as how lipids can make these processes more or less favourable. We will also discuss the implications of this work for the free energy landscape during the co-translational folding of alpha helical membrane proteins.
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Affiliation(s)
- Ryan Brady
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Nicola J. Harris
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Grant A. Pellowe
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
| | - Samuel Gulaidi Breen
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K
| | - Paula J. Booth
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London SE1 1DB, U.K
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20
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Harris NJ, Reading E, Booth PJ. Cell-Free Synthesis Strategies to Probe Co-translational Folding of Proteins Within Lipid Membranes. Methods Mol Biol 2022; 2433:273-292. [PMID: 34985751 DOI: 10.1007/978-1-0716-1998-8_17] [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] [Indexed: 06/14/2023]
Abstract
In order to comprehend the molecular basis of transmembrane protein biogenesis, methods are required that are capable of investigating the co-translational folding of these hydrophobic proteins. Equally, in artificial cell studies, controllable methods are desirable for in situ synthesis of membrane proteins that then direct reactions in the synthetic cell membrane. Here we describe a method that exploits cell-free expression systems and tunable membrane mimetics to facilitate co-translational studies. Alteration of the lipid bilayer composition improves the efficiency of the folding system. The approach also enables membrane transport proteins to be made and inserted into artificial cell platforms such as droplet interface bilayers. Importantly, this gives a new facet to the droplet networks by enabling specific transport of molecules across the synthetic bilayer against a concentration gradient. This method also includes a protocol to pause and restart translation of membrane proteins at specified positions during their co-translational folding. This stop-start strategy provides an avenue to investigate whether the proteins fold in sequence order, or if the correct fold of N-terminal regions is reliant on the synthesis of downstream residues.
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Affiliation(s)
| | - Eamonn Reading
- Department of Chemistry, King's College London, London, UK
| | - Paula J Booth
- Department of Chemistry, King's College London, London, UK.
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21
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Dorner J, Korn P, Gruhle K, Ramsbeck D, Garamus VM, Lilie H, Meister A, Schwieger C, Ihling C, Sinz A, Drescher S. A Diazirine-Modified Membrane Lipid to Study Peptide/Lipid Interactions - Chances and Challenges. Chemistry 2021; 27:14586-14593. [PMID: 34406694 PMCID: PMC8597076 DOI: 10.1002/chem.202102048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Indexed: 01/19/2023]
Abstract
Although incorporation of photo‐activatable lipids into membranes potentially opens up novel avenues for investigating interactions with proteins, the question of whether diazirine‐modified lipids are suitable for such studies, remains under debate. Focusing on the potential for studying lipid/peptide interactions by cross‐linking mass spectrometry (XL‐MS), we developed a diazirine‐modified lipid (DiazPC), and examined its behaviour in membranes incorporating the model α‐helical peptide LAVA20. We observed an unexpected backfolding of the diazirine‐containing stearoyl chain of the lipid. This surprising behaviour challenges the potential application of DiazPC for future XL‐MS studies of peptide and protein/lipid interactions. The observations made for DiazPC most likely represent a general phenomenon for any type of membrane lipids with a polar moiety incorporated into the alkyl chain. Our finding is therefore of importance for future protein/lipid interaction studies relying on modified lipid probes.
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Affiliation(s)
- Julia Dorner
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
| | - Patricia Korn
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
| | - Kai Gruhle
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany.,Institute of Pharmacy-Biophysical Pharmacy, MLU Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120, Halle (Saale), Germany
| | - Daniel Ramsbeck
- Fraunhofer Institute for Cell Therapy and Immunology IZI, Weinbergweg 22, 06120, Halle (Saale), Germany.,Institute of Pharmacy, University Leipzig, Brüderstr. 34, 04103, Leipzig, Germany
| | - Vasil M Garamus
- Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502, Geesthacht, Germany
| | - Hauke Lilie
- Institute for Biochemistry and Biotechnology-Technical Biochemistry, MLU Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
| | - Annette Meister
- Institute of Biochemistry and Biotechnology-Physical Biotechnology Charles Tanford Protein Center, MLU Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany.,Interdisciplinary Research Center HALOmem, MLU Halle-Wittenberg Charles Tanford Protein Center, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany
| | - Christian Schwieger
- Interdisciplinary Research Center HALOmem, MLU Halle-Wittenberg Charles Tanford Protein Center, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany
| | - Christian Ihling
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany.,Center for Structural Mass Spectrometry, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
| | - Andrea Sinz
- Institute of Pharmacy-Pharmaceutical Chemistry and Bioanalytics, Martin Luther University (MLU) Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany.,Center for Structural Mass Spectrometry, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
| | - Simon Drescher
- Institute of Pharmacy-Biophysical Pharmacy, MLU Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, 06120, Halle (Saale), Germany.,Phospholipid Research Center, Im Neuenheimer Feld 515, 69120, Heidelberg, Germany
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22
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Abstract
Membrane proteins (MPs) play essential roles in numerous cellular processes. Because around 70% of the currently marketed drugs target MPs, a detailed understanding of their structure, binding properties, and functional dynamics in a physiologically relevant environment is crucial for a more detailed understanding of this important protein class. We here summarize the benefits of using lipid nanodiscs for NMR structural investigations and provide a detailed overview of the currently used lipid nanodisc systems as well as their applications in solution-state NMR. Despite the increasing use of other structural methods for the structure determination of MPs in lipid nanodiscs, solution NMR turns out to be a versatile tool to probe a wide range of MP features, ranging from the structure determination of small to medium-sized MPs to probing ligand and partner protein binding as well as functionally relevant dynamical signatures in a lipid nanodisc setting. We will expand on these topics by discussing recent NMR studies with lipid nanodiscs and work out a key workflow for optimizing the nanodisc incorporation of an MP for subsequent NMR investigations. With this, we hope to provide a comprehensive background to enable an informed assessment of the applicability of lipid nanodiscs for NMR studies of a particular MP of interest.
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Affiliation(s)
- Umut Günsel
- Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Strasse 2, 85748 Garching, Germany
| | - Franz Hagn
- Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Strasse 2, 85748 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
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23
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Abstract
Native mass spectrometry (MS) is aimed at preserving and determining the native structure, composition, and stoichiometry of biomolecules and their complexes from solution after they are transferred into the gas phase. Major improvements in native MS instrumentation and experimental methods over the past few decades have led to a concomitant increase in the complexity and heterogeneity of samples that can be analyzed, including protein-ligand complexes, protein complexes with multiple coexisting stoichiometries, and membrane protein-lipid assemblies. Heterogeneous features of these biomolecular samples can be important for understanding structure and function. However, sample heterogeneity can make assignment of ion mass, charge, composition, and structure very challenging due to the overlap of tens or even hundreds of peaks in the mass spectrum. In this review, we cover data analysis, experimental, and instrumental advances and strategies aimed at solving this problem, with an in-depth discussion of theoretical and practical aspects of the use of available deconvolution algorithms and tools. We also reflect upon current challenges and provide a view of the future of this exciting field.
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Affiliation(s)
- Amber D Rolland
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403-1253, United States
| | - James S Prell
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, Oregon 97403-1253, United States.,Materials Science Institute, University of Oregon, Eugene, Oregon 97403-1252, United States
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24
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Hu X, Li F, Xia F, Wang Q, Lin P, Wei M, Gong L, Low LE, Lee JY, Ling D. Dynamic nanoassembly-based drug delivery system (DNDDS): Learning from nature. Adv Drug Deliv Rev 2021; 175:113830. [PMID: 34139254 DOI: 10.1016/j.addr.2021.113830] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/19/2021] [Accepted: 06/10/2021] [Indexed: 12/18/2022]
Abstract
Dynamic nanoassembly-based drug delivery system (DNDDS) has evolved from being a mere curiosity to emerging as a promising strategy for high-performance diagnosis and/or therapy of various diseases. However, dynamic nano-bio interaction between DNDDS and biological systems remains poorly understood, which can be critical for precise spatiotemporal and functional control of DNDDS in vivo. To deepen the understanding for fine control over DNDDS, we aim to explore natural systems as the root of inspiration for researchers from various fields. This review highlights ingenious designs, nano-bio interactions, and controllable functionalities of state-of-the-art DNDDS under endogenous or exogenous stimuli, by learning from nature at the molecular, subcellular, and cellular levels. Furthermore, the assembly strategies and response mechanisms of tailor-made DNDDS based on the characteristics of various diseased microenvironments are intensively discussed. Finally, the current challenges and future perspectives of DNDDS are briefly commented.
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25
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Frick M, Schwieger C, Schmidt C. Liposomes as Carriers of Membrane-Associated Proteins and Peptides for Mass Spectrometric Analysis. Angew Chem Int Ed Engl 2021; 60:11523-11530. [PMID: 33599387 PMCID: PMC8252038 DOI: 10.1002/anie.202101242] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 12/11/2022]
Abstract
Membrane proteins are key players of the cell. Their structure and the interactions they form with their lipid environment are required to understand their function. Here we explore liposomes as membrane mimetics for mass spectrometric analysis of peripheral membrane proteins and peptides. Liposomes are advantageous over other membrane mimetics in that they are easy to prepare, can be varied in size and composition, and are suitable for functional assays. We demonstrate that they dissociate into lipid clusters in the gas phase of a mass spectrometer while intact protein and protein-lipid complexes are retained. We exemplify this approach by employing different liposomes including proteoliposomes of two model peptides/proteins differing in size. Our results pave the way for the general application of liposomes for mass spectrometric analysis of membrane-associated proteins.
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Affiliation(s)
- Melissa Frick
- Interdisciplinary Research Center HALOmemCharles Tanford Protein CenterInstitute for Biochemistry and BiotechnologyMartin Luther University Halle-WittenbergKurt-Mothes-Strasse 3a06120HalleGermany
| | - Christian Schwieger
- Interdisciplinary Research Center HALOmemCharles Tanford Protein CenterInstitute for Biochemistry and BiotechnologyMartin Luther University Halle-WittenbergKurt-Mothes-Strasse 3a06120HalleGermany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmemCharles Tanford Protein CenterInstitute for Biochemistry and BiotechnologyMartin Luther University Halle-WittenbergKurt-Mothes-Strasse 3a06120HalleGermany
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26
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Frick M, Schwieger C, Schmidt C. Liposomen als Überträger membranassoziierter Proteine und Peptide für die massenspektrometrische Analyse. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202101242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Melissa Frick
- Interdisziplinäre wissenschaftliche Einrichtung Charles-Tanford-Proteinzentrum Institut für Biochemie und Biotechnologie Martin-Luther-Universität Halle-Wittenberg Kurt-Mothes-Straße 3a 06120 Halle Deutschland
| | - Christian Schwieger
- Interdisziplinäre wissenschaftliche Einrichtung Charles-Tanford-Proteinzentrum Institut für Biochemie und Biotechnologie Martin-Luther-Universität Halle-Wittenberg Kurt-Mothes-Straße 3a 06120 Halle Deutschland
| | - Carla Schmidt
- Interdisziplinäre wissenschaftliche Einrichtung Charles-Tanford-Proteinzentrum Institut für Biochemie und Biotechnologie Martin-Luther-Universität Halle-Wittenberg Kurt-Mothes-Straße 3a 06120 Halle Deutschland
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27
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Ion mobility-mass spectrometry reveals the role of peripheral myelin protein dimers in peripheral neuropathy. Proc Natl Acad Sci U S A 2021; 118:2015331118. [PMID: 33893233 DOI: 10.1073/pnas.2015331118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Peripheral myelin protein (PMP22) is an integral membrane protein that traffics inefficiently even in wild-type (WT) form, with only 20% of the WT protein reaching its final plasma membrane destination in myelinating Schwann cells. Misfolding of PMP22 has been identified as a key factor in multiple peripheral neuropathies, including Charcot-Marie-Tooth disease and Dejerine-Sottas syndrome. While biophysical analyses of disease-associated PMP22 mutants show altered protein stabilities, leading to reduced surface trafficking and loss of PMP22 function, it remains unclear how destabilization of PMP22 mutations causes mistrafficking. Here, native ion mobility-mass spectrometry (IM-MS) is used to compare the gas phase stabilities and abundances for an array of mutant PM22 complexes. We find key differences in the PMP22 mutant stabilities and propensities to form homodimeric complexes. Of particular note, we observe that severely destabilized forms of PMP22 exhibit a higher propensity to dimerize than WT PMP22. Furthermore, we employ lipid raft-mimicking SCOR bicelles to study PMP22 mutants, and find that the differences in dimer abundances are amplified in this medium when compared to micelle-based data, with disease mutants exhibiting up to 4 times more dimer than WT when liberated from SCOR bicelles. We combine our findings with previous cellular data to propose that the formation of PMP22 dimers from destabilized monomers is a key element of PMP22 mistrafficking.
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28
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Zaitseva E, Obergrussberger A, Weichbrodt C, Boukhet M, Bernhard F, Hein C, Baaken G, Fertig N, Behrends JC. Electrophysiology on Channel-Forming Proteins in Artificial Lipid Bilayers: Next-Generation Instrumentation for Multiple Recordings in Parallel. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2188:67-92. [PMID: 33119847 DOI: 10.1007/978-1-0716-0818-0_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Artificial lipid bilayers have been used for several decades to study channel-forming pores and ion channels in membranes. Until recently, the classical two-chamber setups have been primarily used for studying the biophysical properties of pore forming proteins. Within the last 10 years, instruments for automated lipid bilayer measurements have been developed and are now commercially available. This chapter focuses on protein purification and reconstitution of channel-forming proteins into lipid bilayers using a classic setup and on the commercially available systems, the Orbit mini and Orbit 16.
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Affiliation(s)
| | | | | | | | - Frank Bernhard
- Institute of Biophysical Chemistry & Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Christopher Hein
- Institute of Biophysical Chemistry & Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt am Main, Germany
| | | | | | - Jan C Behrends
- Laboratory for Membrane Physiology and Technology, Department of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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29
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Scratching the surface: native mass spectrometry of peripheral membrane protein complexes. Biochem Soc Trans 2021; 48:547-558. [PMID: 32129823 PMCID: PMC7192793 DOI: 10.1042/bst20190787] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/09/2020] [Accepted: 02/11/2020] [Indexed: 02/06/2023]
Abstract
A growing number of integral membrane proteins have been shown to tune their activity by selectively interacting with specific lipids. The ability to regulate biological functions via lipid interactions extends to the diverse group of proteins that associate only peripherally with the lipid bilayer. However, the structural basis of these interactions remains challenging to study due to their transient and promiscuous nature. Recently, native mass spectrometry has come into focus as a new tool to investigate lipid interactions in membrane proteins. Here, we outline how the native MS strategies developed for integral membrane proteins can be applied to generate insights into the structure and function of peripheral membrane proteins. Specifically, native MS studies of proteins in complex with detergent-solubilized lipids, bound to lipid nanodiscs, and released from native-like lipid vesicles all shed new light on the role of lipid interactions. The unique ability of native MS to capture and interrogate protein–protein, protein–ligand, and protein–lipid interactions opens exciting new avenues for the study of peripheral membrane protein biology.
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30
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Hammerschmid D, van Dyck JF, Sobott F, Calabrese AN. Interrogating Membrane Protein Structure and Lipid Interactions by Native Mass Spectrometry. Methods Mol Biol 2021; 2168:233-261. [PMID: 33582995 DOI: 10.1007/978-1-0716-0724-4_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
Native mass spectrometry and native ion mobility mass spectrometry are now established techniques in structural biology, with recent work developing these methods for the study of integral membrane proteins reconstituted in both lipid bilayer and detergent environments. Here we show how native mass spectrometry can be used to interrogate integral membrane proteins, providing insights into conformation, oligomerization, subunit composition/stoichiometry, and interactions with detergents/lipids/drugs. Furthermore, we discuss the sample requirements and experimental considerations unique to integral membrane protein native mass spectrometry research.
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Affiliation(s)
- Dietmar Hammerschmid
- Protein Chemistry, Proteomics and Epigenetic Signalling (PPES), Department of Biomedical Sciences, University of Antwerp, Wilrijk, Belgium.,Biomolecular & Analytical Mass Spectrometry Group, Chemistry Department, University of Antwerp, Antwerp, Belgium
| | - Jeroen F van Dyck
- Biomolecular & Analytical Mass Spectrometry Group, Chemistry Department, University of Antwerp, Antwerp, Belgium
| | - Frank Sobott
- Biomolecular & Analytical Mass Spectrometry Group, Chemistry Department, University of Antwerp, Antwerp, Belgium.,Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, UK.,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Antonio N Calabrese
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds, UK. .,Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK.
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31
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Affiliation(s)
- James E. Keener
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Guozhi Zhang
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
| | - Michael T. Marty
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721, USA
- Bio5 Institute, University of Arizona, Tucson, AZ 85721, USA
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32
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Abstract
Cell-free protein expression systems and lipid nanoparticle technologies are core platforms for membrane protein synthesis. The implementation of preassembled nanodiscs allows the co-translational insertion of membrane proteins into tailored lipid bilayers in the absence of any artificial hydrophobic compounds. This strategy is particularly interesting for detergent sensitive or otherwise critical membrane proteins such as G-protein-coupled receptors (GPCRs). Cell-free expression reactions are completed within a day and the formed GPCR/nanodisc particles can be purified directly out of the reaction mixture by affinity tags and without any further manipulation. The streamlined procedure reduces risk of GPCR denaturation and the sample quality can further be supported by supplying chaperones or other beneficial compounds directly into the expression reactions.GPCRs inserted into nanoparticle membranes are excellent tools for a variety of applications such as ligand screening, engineering or even structural characterization. In this chapter, we provide protocols for the reaction set-up and efficient cell-free production of functionally folded GPCRs reaching μM concentrations in the final expression reactions. We further exemplify the tuning of GPCR sample quality and discuss their application for throughput ligand screening and for the analysis of ligand-binding characteristics.
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33
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Harvey SR, VanAernum ZL, Kostelic MM, Marty MT, Wysocki VH. Probing the structure of nanodiscs using surface-induced dissociation mass spectrometry. Chem Commun (Camb) 2020; 56:15651-15654. [PMID: 33355562 PMCID: PMC7943047 DOI: 10.1039/d0cc05531j] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In the study of membrane proteins and antimicrobial peptides, nanodiscs have emerged as a valuable membrane mimetic to solubilze these molecules in a lipid bilayer. We present the structural characterization of nanodiscs using native mass spectrometry and surface-induced dissociation, which are powerful tools in structural biology.
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Affiliation(s)
- Sophie R Harvey
- Department of Chemistry and Biochemistry and Resource for Native Mass Spectrometry Guided Structural Biology, The Ohio State University, Columbus, OH, USA.
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34
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Mezhyrova J, Martin J, Peetz O, Dötsch V, Morgner N, Ma Y, Bernhard F. Membrane insertion mechanism and molecular assembly of the bacteriophage lysis toxin ΦX174‐E. FEBS J 2020; 288:3300-3316. [DOI: 10.1111/febs.15642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/23/2020] [Accepted: 11/02/2020] [Indexed: 02/02/2023]
Affiliation(s)
- Julija Mezhyrova
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance Goethe University Frankfurt am Main Germany
| | - Janosch Martin
- Institute of Physical and Theoretical Chemistry Goethe University Frankfurt am Main Germany
| | - Oliver Peetz
- Institute of Physical and Theoretical Chemistry Goethe University Frankfurt am Main Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance Goethe University Frankfurt am Main Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry Goethe University Frankfurt am Main Germany
| | - Yi Ma
- School of Biology and Biological Engineering South China University of Technology Guangzhou China
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering South China University of Technology Guangzhou China
| | - Frank Bernhard
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance Goethe University Frankfurt am Main Germany
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35
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Marty MT. Nanodiscs and Mass Spectrometry: Making Membranes Fly. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2020; 458:116436. [PMID: 33100891 PMCID: PMC7584149 DOI: 10.1016/j.ijms.2020.116436] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Cells are surrounded by a protective lipid bilayer membrane, and membrane proteins in the bilayer control the flow of chemicals, information, and energy across this barrier. Many therapeutics target membrane proteins, and some directly target the lipid membrane itself. However, interactions within biological membranes are challenging to study due to their heterogeneity and insolubility. Mass spectrometry (MS) has become a powerful technique for studying membrane proteins, especially how membrane proteins interact with their surrounding lipid environment. Although detergent micelles are the most common membrane mimetic, nanodiscs are emerging as a promising platform for MS. Nanodiscs, nanoscale lipid bilayers encircled by two scaffold proteins, provide a controllable lipid bilayer for solubilizing membrane proteins. This Young Scientist Perspective focuses on native MS of intact nanodiscs and highlights the unique experiments enabled by making membranes fly, including studying membrane protein-lipid interactions and exploring the specificity of fragile transmembrane peptide complexes. It will also explore current challenges and future perspectives for interfacing nanodiscs with MS.
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Affiliation(s)
- Michael T Marty
- Department of Chemistry and Biochemistry and Bio5 Institute, University of Arizona, Tucson, AZ 85721
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36
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LILBID laser dissociation curves: a mass spectrometry-based method for the quantitative assessment of dsDNA binding affinities. Sci Rep 2020; 10:20398. [PMID: 33230224 PMCID: PMC7683618 DOI: 10.1038/s41598-020-76867-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 10/28/2020] [Indexed: 11/20/2022] Open
Abstract
One current goal in native mass spectrometry is the assignment of binding affinities to noncovalent complexes. Here we introduce a novel implementation of the existing laser-induced liquid bead ion desorption (LILBID) mass spectrometry method: this new method, LILBID laser dissociation curves, assesses binding strengths quantitatively. In all LILBID applications, aqueous sample droplets are irradiated by 3 µm laser pulses. Variation of the laser energy transferred to the droplet during desorption affects the degree of complex dissociation. In LILBID laser dissociation curves, laser energy transfer is purposely varied, and a binding affinity is calculated from the resulting complex dissociation. A series of dsDNAs with different binding affinities was assessed using LILBID laser dissociation curves. The binding affinity results from the LILBID laser dissociation curves strongly correlated with the melting temperatures from UV melting curves and with dissociation constants from isothermal titration calorimetry, standard solution phase methods. LILBID laser dissociation curve data also showed good reproducibility and successfully predicted the melting temperatures and dissociation constants of three DNA sequences. LILBID laser dissociation curves are a promising native mass spectrometry binding affinity method, with reduced time and sample consumption compared to melting curves or titrations.
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37
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Fantin SM, Huang H, Sanders CR, Ruotolo BT. Collision-Induced Unfolding Differentiates Functional Variants of the KCNQ1 Voltage Sensor Domain. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:2348-2355. [PMID: 32960579 PMCID: PMC8106873 DOI: 10.1021/jasms.0c00288] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The KCNQ1 voltage-gated potassium channel regulates the repolarization of cardiac cells, and a plurality of point mutations in its voltage-sensing domain (VSD) are associated with toxic gain or loss of pore function, resulting in disease. As is the case with many disease-associated membrane proteins, there are hundreds of human variants of interest identified for KCNQ1; however, a significant portion of these variants have not been characterized in relation to their functional and disease associations. Additionally, as the VSD consists of four transmembrane helices, studies into dynamic structural differences among KCNQ1 VSD variants are hindered by the current limitations and deficits in the high-resolution structure determination of membrane proteins. Here, we use native ion mobility-mass spectrometry and collision-induced unfolding (CIU) to address the need for a high throughput-compatible method for the structural characterization of membrane protein variants of unknown significance using the KCNQ1 VSD as a model system. We perform CIU on wild-type and three mutant KCNQ1 VSD forms associated with the toxic gain or loss of function and show through both automated feature detection and comprehensive difference analysis of the CIU data sets that the variants are clearly grouped by function and disease association. We also construct a classification scheme based on the CIU data sets, which is able to differentiate the variant functional groups and classify a recently characterized variant to its correct grouping. Further, we probe the stability of the KCNQ1 VSD variants when liberated from C12E8 micelles at pH 8.0 and find preliminary evidence that the R231C mutation associated with the gain of the pore function is destabilized relative to the wild-type and loss of function variants.
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Affiliation(s)
- Sarah M. Fantin
- University of Michigan Department of Chemistry, Ann Arbor, Michigan 48109, United States
| | - Hui Huang
- Vanderbilt University, Department of Biochemistry, Nashville, Tennessee 37232, United States
| | - Charles R. Sanders
- Vanderbilt University, Department of Biochemistry, Nashville, Tennessee 37232, United States
| | - Brandon T. Ruotolo
- University of Michigan Department of Chemistry, Ann Arbor, Michigan 48109, United States
- Corresponding Author:
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38
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Corin K, Bowie JU. How bilayer properties influence membrane protein folding. Protein Sci 2020; 29:2348-2362. [PMID: 33058341 DOI: 10.1002/pro.3973] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/07/2020] [Accepted: 10/09/2020] [Indexed: 01/24/2023]
Abstract
The question of how proteins manage to organize into a unique three-dimensional structure has been a major field of study since the first protein structures were determined. For membrane proteins, the question is made more complex because, unlike water-soluble proteins, the solvent is not homogenous or even unique. Each cell and organelle has a distinct lipid composition that can change in response to environmental stimuli. Thus, the study of membrane protein folding requires not only understanding how the unfolded chain navigates its way to the folded state, but also how changes in bilayer properties can affect that search. Here we review what we know so far about the impact of lipid composition on bilayer physical properties and how those properties can affect folding. A better understanding of the lipid bilayer and its effects on membrane protein folding is not only important for a theoretical understanding of the folding process, but can also have a practical impact on our ability to work with and design membrane proteins.
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Affiliation(s)
- Karolina Corin
- Department of Chemistry and Biochemistry, Molecular Biology Institute, UCLA-DOE Institute, University of California, Los Angeles, California, USA
| | - James U Bowie
- Department of Chemistry and Biochemistry, Molecular Biology Institute, UCLA-DOE Institute, University of California, Los Angeles, California, USA
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39
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Barth M, Schmidt C. Native mass spectrometry-A valuable tool in structural biology. JOURNAL OF MASS SPECTROMETRY : JMS 2020; 55:e4578. [PMID: 32662584 DOI: 10.1002/jms.4578] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 05/16/2023]
Abstract
Proteins and the complexes they form with their ligands are the players of cellular action. Their function is directly linked with their structure making the structural analysis of protein-ligand complexes essential. Classical techniques of structural biology include X-ray crystallography, nuclear magnetic resonance spectroscopy and recently distinguished cryo-electron microscopy. However, protein-ligand complexes are often dynamic and heterogeneous and consequently challenging for these techniques. Alternative approaches are therefore needed and gained importance during the last decades. One alternative is native mass spectrometry, which is the analysis of intact protein complexes in the gas phase. To achieve this, sample preparation and instrument conditions have to be optimised. Native mass spectrometry then reveals stoichiometry, protein interactions and topology of protein assemblies. Advanced techniques such as ion mobility and high-resolution mass spectrometry further add to the range of applications and deliver information on shape and microheterogeneity of the complexes. In this tutorial, we explain the basics of native mass spectrometry including sample requirements, instrument modifications and interpretation of native mass spectra. We further discuss the developments of native mass spectrometry and provide example spectra and applications.
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Affiliation(s)
- Marie Barth
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Institute for Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle, Germany
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40
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Harris NJ, Pellowe GA, Booth PJ. Cell-free expression tools to study co-translational folding of alpha helical membrane transporters. Sci Rep 2020; 10:9125. [PMID: 32499529 PMCID: PMC7272624 DOI: 10.1038/s41598-020-66097-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/15/2020] [Indexed: 11/28/2022] Open
Abstract
Most helical membrane proteins fold co-translationally during unidirectional polypeptide elongation by the ribosome. Studies thus far, however, have largely focussed on refolding full-length proteins from artificially induced denatured states that are far removed from the natural co-translational process. Cell-free translation offers opportunities to remedy this deficit in folding studies and has previously been used for membrane proteins. We exploit this cell-free approach to develop tools to probe co-translational folding. We show that two transporters from the ubiquitous Major Facilitator Superfamily can successfully insert into a synthetic bilayer without the need for translocon insertase apparatus that is essential in vivo. We also assess the cooperativity of domain insertion, by expressing the individual transporter domains cell-free. Furthermore, we manipulate the cell-free reaction to pause and re-start protein synthesis at specific points in the protein sequence. We find that full-length protein can still be made when stalling after the first N terminal helix has inserted into the bilayer. However, stalling after the first three helices have exited the ribosome cannot be successfully recovered. These three helices cannot insert stably when ribosome-bound during co-translational folding, as they require insertion of downstream helices.
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Affiliation(s)
- Nicola J Harris
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Grant A Pellowe
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Paula J Booth
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London, SE1 1DB, UK.
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41
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Zhang G, Keener JE, Marty MT. Measuring Remodeling of the Lipid Environment Surrounding Membrane Proteins with Lipid Exchange and Native Mass Spectrometry. Anal Chem 2020; 92:5666-5669. [PMID: 32250609 DOI: 10.1021/acs.analchem.0c00786] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Due to their crucial biochemical roles, membrane proteins are important drug targets. Although it is clear that lipids can influence membrane protein function, the chemistry of lipid binding remains difficult to study because protein-lipid interactions are polydisperse, competitive, and transient. Furthermore, detergents, which are often used to solubilize membrane proteins in micelles, may disrupt lipid interactions that occur in bilayers. Here, we present two new approaches to quantify protein-lipid interactions in bilayers and understand how membrane proteins remodel their surrounding lipid environment. First, we used mass spectrometry (MS) to measure the exchange of lipids between lipoprotein nanodiscs with and without an embedded membrane protein. Shifts in the lipid distribution toward the membrane protein nanodiscs revealed lipid binding, and titrations allowed measurement of the optimal lipid composition for the membrane protein. Second, we used native or nondenaturing MS to ionize membrane protein nanodiscs with heterogeneous lipids. Ejecting the membrane protein complex with bound lipids in the mass spectrometer revealed enrichment of specific lipids around the membrane protein. Both new approaches showed that the E. coli ammonium transporter AmtB prefers phosphatidylglycerol lipids overall but has a minor affinity for phosphatidylcholine lipids.
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Häusler E, Fredriksson K, Goba I, Peters C, Raltchev K, Sperl L, Steiner A, Weinkauf S, Hagn F. Quantifying the insertion of membrane proteins into lipid bilayer nanodiscs using a fusion protein strategy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183190. [DOI: 10.1016/j.bbamem.2020.183190] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/13/2022]
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Bender J, Schmidt C. Mass spectrometry of membrane protein complexes. Biol Chem 2020; 400:813-829. [PMID: 30956223 DOI: 10.1515/hsz-2018-0443] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/25/2019] [Indexed: 12/24/2022]
Abstract
Membrane proteins are key players in the cell. Due to their hydrophobic nature they require solubilising agents such as detergents or membrane mimetics during purification and, consequently, are challenging targets in structural biology. In addition, their natural lipid environment is crucial for their structure and function further hampering their analysis. Alternative approaches are therefore required when the analysis by conventional techniques proves difficult. In this review, we highlight the broad application of mass spectrometry (MS) for the characterisation of membrane proteins and their interactions with lipids. We show that MS unambiguously identifies the protein and lipid components of membrane protein complexes, unravels their three-dimensional arrangements and further provides clues of protein-lipid interactions.
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Affiliation(s)
- Julian Bender
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Centre, Martin Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Str. 3a, D-06120 Halle, Germany
| | - Carla Schmidt
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Centre, Martin Luther University Halle-Wittenberg, Institute for Biochemistry and Biotechnology, Kurt-Mothes-Str. 3a, D-06120 Halle, Germany
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Fantin SM, Parson KF, Niu S, Liu J, Polasky DA, Dixit SM, Ferguson-Miller SM, Ruotolo BT. Collision Induced Unfolding Classifies Ligands Bound to the Integral Membrane Translocator Protein. Anal Chem 2019; 91:15469-15476. [PMID: 31743004 DOI: 10.1021/acs.analchem.9b03208] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Membrane proteins represent most current therapeutic targets, yet remain understudied due to their insolubility in aqueous solvents and generally low yields during purification and expression. Ion mobility-mass spectrometry and collision induced unfolding experiments have recently garnered attention as methods capable of directly detecting and quantifying ligand binding within a wide range of membrane protein systems. Despite prior success, ionized surfactant often creates chemical noise patterns resulting in significant challenges surrounding the study of small membrane protein-ligand complexes. Here, we present a new data analysis workflow that overcomes such chemical noise and then utilize this approach to quantify and classify ligand binding associated with the 36 kDa dimer of translocator protein (TSPO). Following our denoising protocol, we detect separate gas-phase unfolding signatures for lipid and protoporphyrin TSPO binders, molecular classes that likely interact with separate regions of the protein surface. Further, a detailed classification analysis reveals that lipid alkyl chain saturation levels can be detected within our gas-phase protein unfolding data. We combine these data and classification schemes with mass spectra acquired directly from liquid-liquid extracts to propose an identity for a previously unknown endogenous TSPO ligand.
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Affiliation(s)
- Sarah M Fantin
- Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Kristine F Parson
- Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Shuai Niu
- Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Jian Liu
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Daniel A Polasky
- Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Sugyan M Dixit
- Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Shelagh M Ferguson-Miller
- Department of Biochemistry and Molecular Biology , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Brandon T Ruotolo
- Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
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Kourkoulou A, Grevias P, Lambrinidis G, Pyle E, Dionysopoulou M, Politis A, Mikros E, Byrne B, Diallinas G. Specific Residues in a Purine Transporter Are Critical for Dimerization, ER Exit, and Function. Genetics 2019; 213:1357-1372. [PMID: 31611232 PMCID: PMC6893392 DOI: 10.1534/genetics.119.302566] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/02/2019] [Indexed: 12/11/2022] Open
Abstract
Transporters are transmembrane proteins that mediate the selective translocation of solutes across biological membranes. Recently, we have shown that specific interactions with plasma membrane phospholipids are essential for the formation and/or stability of functional dimers of the purine transporter UapA, a prototypic eukaryotic member of the ubiquitous nucleobase ascorbate transporter (NAT) family. Here, we provide strong evidence that distinct interactions of UapA with membrane lipids are essential for ab initio formation of functional dimers in the ER, or ER exit and further subcellular trafficking. Through genetic screens, we identify mutations that restore defects in dimer formation and/or trafficking. Suppressors of defective dimerization restore ab initio formation of UapA dimers in the ER. Most of these suppressors are located in the movable core domain, but also in the core-dimerization interface and in residues of the dimerization domain exposed to lipids. Molecular dynamics suggest that the majority of suppressors stabilize interhelical interactions in the core domain and thus assist the formation of functional UapA dimers. Among suppressors restoring dimerization, a specific mutation, T401P, was also isolated independently as a suppressor restoring trafficking, suggesting that stabilization of the core domain restores function by sustaining structural defects caused by the abolishment of essential interactions with specific lipids. Importantly, the introduction of mutations topologically equivalent to T401P into a rat homolog of UapA, namely rSNBT1, permitted the functional expression of a mammalian NAT in Aspergillus nidulans Thus, our results provide a potential route for the functional expression and manipulation of mammalian transporters in the model Aspergillus system.
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Affiliation(s)
- Anezia Kourkoulou
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15784, Greece
| | - Pothos Grevias
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15784, Greece
| | - George Lambrinidis
- Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis, 15771, Greece
| | - Euan Pyle
- Department of Life Sciences, Imperial College London, SW7 2AZ, UK
- Department of Chemistry, King's College London, SE1 1DB, UK
| | - Mariangela Dionysopoulou
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15784, Greece
| | | | - Emmanuel Mikros
- Department of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis, 15771, Greece
| | - Bernadette Byrne
- Department of Life Sciences, Imperial College London, SW7 2AZ, UK
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15784, Greece
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Diallinas G, Martzoukou O. Transporter membrane traffic and function: lessons from a mould. FEBS J 2019; 286:4861-4875. [DOI: 10.1111/febs.15078] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/26/2019] [Accepted: 09/30/2019] [Indexed: 12/16/2022]
Affiliation(s)
- George Diallinas
- Department of Biology National and Kapodistrian University of Athens Greece
| | - Olga Martzoukou
- Department of Biology National and Kapodistrian University of Athens Greece
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Federman RS, Boguraev AS, Heim EN, DiMaio D. Biologically Active Ultra-Simple Proteins Reveal Principles of Transmembrane Domain Interactions. J Mol Biol 2019; 431:3753-3770. [PMID: 31301406 DOI: 10.1016/j.jmb.2019.07.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 11/30/2022]
Abstract
Specific interactions between the helical membrane-spanning domains of transmembrane proteins play central roles in the proper folding and oligomerization of these proteins. However, the relationship between the hydrophobic amino acid sequences of transmembrane domains and their functional interactions is in most cases unknown. Here, we use ultra-simple artificial proteins to systematically study the sequence basis for transmembrane domain interactions. We show that most short homopolymeric polyleucine transmembrane proteins containing single amino acid substitutions can activate the platelet-derived growth factor β receptor or the erythropoietin receptor in cultured mouse cells, resulting in cell transformation or proliferation. These proteins displayed complex patterns of activity that were markedly affected by seemingly minor sequence differences in the ultra-simple protein itself or in the transmembrane domain of the target receptor, and the effects of these sequence differences are not additive. In addition, specific leucine residues along the length of these proteins are required for activity, and the positions of these required leucines differ based on the identity and position of the central substituted amino acid. Our results suggest that these ultra-simple proteins use a variety of molecular mechanisms to activate the same target and that diversification of transmembrane domain sequences over the course of evolution minimized off-target interactions.
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Affiliation(s)
- Ross S Federman
- Department of Immunobiology, Yale School of Medicine, PO Box 208011, New Haven, CT 06520-8011, USA
| | - Anna-Sophia Boguraev
- Department of Genetics, Yale School of Medicine, PO Box 208005, New Haven, CT 06520-8005, USA
| | - Erin N Heim
- Department of Genetics, Yale School of Medicine, PO Box 208005, New Haven, CT 06520-8005, USA
| | - Daniel DiMaio
- Department of Genetics, Yale School of Medicine, PO Box 208005, New Haven, CT 06520-8005, USA; Department of Therapeutic Radiology, Yale School of Medicine, PO Box 208040, New Haven, CT 06520-8040, USA; Department of Molecular Biophysics & Biochemistry, Yale School of Medicine, PO Box 208024, New Haven, CT 06520-8024, USA; Yale Cancer Center, PO Box 208028, New Haven, CT 06520-8028, USA.
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Frick M, Schmidt C. Mass spectrometry—A versatile tool for characterising the lipid environment of membrane protein assemblies. Chem Phys Lipids 2019; 221:145-157. [DOI: 10.1016/j.chemphyslip.2019.04.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/28/2019] [Accepted: 04/01/2019] [Indexed: 01/02/2023]
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Abstract
Cell nutrition, detoxification, signalling, homeostasis and response to drugs, processes related to cell growth, differentiation and survival are all mediated by plasma membrane (PM) proteins called transporters. Despite their distinct fine structures, mechanism of function, energetic requirements, kinetics and substrate specificities, all transporters are characterized by a main hydrophobic body embedded in the PM as a series of tightly packed, often intertwined, α-helices that traverse the lipid bilayer in a zigzag mode, connected with intracellular or extracellular loops and hydrophilic N- and C-termini. Whereas longstanding genetic, biochemical and biophysical evidence suggests that specific transmembrane segments, and also their connecting loops, are responsible for substrate recognition and transport dynamics, emerging evidence also reveals the functional importance of transporter N- and C-termini, in respect to transport catalysis, substrate specificity, subcellular expression, stability and signalling. This review highlights selected prototypic examples of transporters in which their termini play important roles in their functioning.
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Affiliation(s)
- Emmanuel Mikros
- Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimioupolis, 15771 Athens, Greece
| | - George Diallinas
- Department of Biology, National and Kapodistrian University of Athens, Panepistimioupolis, 15781 Athens, Greece
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Harris NJ, Booth PJ. Co-Translational Protein Folding in Lipid Membranes. Trends Biochem Sci 2019; 44:729-730. [PMID: 31186134 DOI: 10.1016/j.tibs.2019.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/20/2019] [Indexed: 11/26/2022]
Affiliation(s)
- Nicola J Harris
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Paula J Booth
- King's College London, Department of Chemistry, Britannia House, 7 Trinity Street, London, SE1 1DB, UK.
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