1
|
Kai L, Sonal, Heermann T, Schwille P. Reconstitution of a Reversible Membrane Switch via Prenylation by One-Pot Cell-Free Expression. ACS Synth Biol 2022; 12:108-119. [PMID: 36445320 PMCID: PMC9872162 DOI: 10.1021/acssynbio.2c00406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reversible membrane targeting of proteins is one of the key regulators of cellular interaction networks, for example, for signaling and polarization. So-called "membrane switches" are thus highly attractive targets for the design of minimal cells but have so far been tricky to reconstitute in vitro. Here, we introduce cell-free prenylated protein synthesis (CFpPS), which enables the synthesis and membrane targeting of proteins in a single reaction mix including the prenylation machinery. CFpPS can confer membrane affinity to any protein via addition of a 4-peptide motif to its C-terminus and offers robust production of prenylated proteins not only in their soluble forms but also in the direct vicinity of biomimetic membranes. Thus, CFpPS enabled us to reconstitute the prenylated polarity hub Cdc42 and its regulatory protein in vitro, implementing a key membrane switch. We propose CFpPS to be a versatile and effective platform for engineering complex features, such as polarity induction, in synthetic cells.
Collapse
Affiliation(s)
- Lei Kai
- Department
of Cellular and Molecular Biophysics, Max
Planck Institute of Biochemistry, D-82152 Martinsried, Germany,School
of Life Sciences, Jiangsu Normal University, Shanghai Road 101, 221116 Xuzhou, P. R. China,. Phone: +86 15852001351
| | - Sonal
- Department
of Cellular and Molecular Biophysics, Max
Planck Institute of Biochemistry, D-82152 Martinsried, Germany,Biosciences
Division, University College London, Gower Street, WC1E 6BT London, U.K.
| | - Tamara Heermann
- Department
of Cellular and Molecular Biophysics, Max
Planck Institute of Biochemistry, D-82152 Martinsried, Germany
| | - Petra Schwille
- Department
of Cellular and Molecular Biophysics, Max
Planck Institute of Biochemistry, D-82152 Martinsried, Germany,. Phone: +49 89 8578 2900
| |
Collapse
|
2
|
Mezhyrova J, Mörs K, Glaubitz C, Dötsch V, Bernhard F. Applications of Cell-Free Synthesized Membrane Protein Precipitates. Methods Mol Biol 2022; 2406:245-266. [PMID: 35089562 DOI: 10.1007/978-1-0716-1859-2_15] [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] [Indexed: 06/14/2023]
Abstract
Cell-free protein expression systems are new core platforms for membrane protein synthesis. Expression in the presence of supplied artificial hydrophobic environments such as nanomembranes or micelles allows the co-translational solubilization and folding of membrane proteins. In the absence of hydrophobic compounds, the synthesized membrane proteins quantitatively precipitate, while frequently still retaining a significant part of folded structural elements. This so-called precipitate-forming cell-free (P-CF) expression mode is a very effective and reliable approach for numerous applications. Even from complex membrane proteins such as G-protein coupled receptors or large transporters, significant amounts of such precipitates can be synthesized within few hours. The precipitates can be solubilized in detergents or reconstituted into membranes for subsequent structural or functional analysis. Harsh denaturation and refolding procedures as known from the treatment of bacterial inclusion bodies are usually not required.This strategy is particularly interesting for applications requiring large amounts of membrane protein or fast access to a sample. It is further an excellent tool for the production of membrane protein antigens suitable for antibody generation. The purification of the precipitates in downstream processing is streamlined as only few proteins from the cell-free lysate may co-precipitate with the synthesized membrane protein. For most applications, a one-step affinity chromatography by taking advantage of small purification tags attached to the membrane protein target is sufficient. We give an overview on current applications of P-CF precipitates and describe the underlying techniques in detail. We furthermore provide protocols for the successful crystallization and NMR analysis of P-CF synthesized membrane proteins exemplified with the diacylglycerol kinase (DAGK). In addition, we describe the functional characterization of a P-CF synthesized large eukaryotic transporter.
Collapse
Affiliation(s)
- Julija Mezhyrova
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University , Frankfurt/Main, Germany
| | - Karsten Mörs
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University , Frankfurt/Main, Germany
| | - Clemens Glaubitz
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University , Frankfurt/Main, Germany
| | - Volker Dötsch
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University , Frankfurt/Main, Germany
| | - Frank Bernhard
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe-University , Frankfurt/Main, Germany.
| |
Collapse
|
3
|
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
| |
Collapse
|
4
|
Kögler LM, Stichel J, Beck-Sickinger AG. Structural investigations of cell-free expressed G protein-coupled receptors. Biol Chem 2020; 401:97-116. [PMID: 31539345 DOI: 10.1515/hsz-2019-0292] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 09/02/2019] [Indexed: 12/11/2022]
Abstract
G protein-coupled receptors (GPCRs) are of great pharmaceutical interest and about 35% of the commercial drugs target these proteins. Still there is huge potential left in finding molecules that target new GPCRs or that modulate GPCRs differentially. For a rational drug design, it is important to understand the structure, binding and activation of the protein of interest. Structural investigations of GPCRs remain challenging, although huge progress has been made in the last 20 years, especially in the generation of crystal structures of GPCRs. This is mostly caused by issues with the expression yield, purity or labeling. Cell-free protein synthesis (CFPS) is an efficient alternative for recombinant expression systems that can potentially address many of these problems. In this article the use of CFPS for structural investigations of GPCRs is reviewed. We compare different CFPS systems, including the cellular basis and reaction configurations, and strategies for an efficient solubilization. Next, we highlight recent advances in the structural investigation of cell-free expressed GPCRs, with special emphasis on the role of photo-crosslinking approaches to investigate ligand binding sites on GPCRs.
Collapse
Affiliation(s)
- Lisa Maria Kögler
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
| | - Jan Stichel
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
| | - Annette G Beck-Sickinger
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, Leipzig University, Brüderstr. 34, D-04103 Leipzig, Germany
| |
Collapse
|
5
|
Henrich E, Löhr F, Mezhyrova J, Laguerre A, Bernhard F, Dötsch V. Synthetic Biology-Based Solution NMR Studies on Membrane Proteins in Lipid Environments. Methods Enzymol 2018; 614:143-185. [PMID: 30611423 DOI: 10.1016/bs.mie.2018.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Although membrane proteins are in the focus of biochemical research for many decades the general knowledge of this important class is far behind soluble proteins. Despite several recent technical developments, the most challenging feature still is the generation of high-quality samples in environments suitable for the selected application. Reconstitution of membrane proteins into lipid bilayers will generate the most native-like environment and is therefore commonly desired. However, it poses tremendous problems to solution-state NMR analysis due to the dramatic increase in particle size resulting in high rotational correlation times. Nevertheless, a few promising strategies for the solution NMR analysis of membrane inserted proteins are emerging and will be discussed in this chapter. We focus on the generation of membrane protein samples in nanodisc membranes by cell-free systems and will describe the characteristic advantages of that platform in providing tailored protein expression and folding environments. We indicate frequent problems that have to be overcome in cell-free synthesis, nanodisc preparation, and customization for samples dedicated for solution-state NMR. Detailed instructions for sample preparation are given, and solution NMR approaches suitable for membrane proteins in bilayers are compiled. We further discuss the current strategies applied for signal detection from such difficult samples and describe the type of information that can be extracted from the various experiments. In summary, a comprehensive guideline for the analysis of membrane proteins in native-like membrane environments by solution-state NMR techniques will be provided.
Collapse
Affiliation(s)
- Erik Henrich
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Frank Löhr
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Julija Mezhyrova
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Aisha Laguerre
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany.
| |
Collapse
|
6
|
Lu M, Zhao X, Xing H, Xun Z, Yang T, Cai C, Wang D, Ding P. Liposome-chaperoned cell-free synthesis for the design of proteoliposomes: Implications for therapeutic delivery. Acta Biomater 2018; 76:1-20. [PMID: 29625253 DOI: 10.1016/j.actbio.2018.03.043] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/20/2018] [Accepted: 03/27/2018] [Indexed: 12/12/2022]
Abstract
Cell-free (CF) protein synthesis has emerged as a powerful technique platform for efficient protein production in vitro. Liposomes have been widely studied as therapeutic carriers due to their biocompatibility, biodegradability, low toxicity, flexible surface manipulation, easy preparation, and higher cargo encapsulation capability. However, rapid immune clearance, insufficient targeting capacity, and poor cytoplasmic delivery efficiency substantially restrict their clinical application. The incorporation of functional membrane proteins (MPs) or peptides allows the transfer of biological properties to liposomes and imparts them with improved circulation, increased targeting, and efficient intracellular delivery. Liposome-chaperoned CF synthesis enables production of proteoliposomes in one-step reaction, which not only substantially simplifies the production procedure but also keeps protein functionality intact. Building off these observations, proteoliposomes with integrated MPs represent an excellent candidate for therapeutic delivery. In this review, we describe recent advances in CF synthesis with emphasis on detailing key factors for improving CF expression efficiency. Furthermore, we provide insights into strategies for rational design of proteoliposomal nanodelivery systems via CF synthesis. STATEMENT OF SIGNIFICANCE Liposome-chaperoned CF synthesis has emerged as a powerful approach for the design of recombinant proteoliposomes in one-step reaction. The incorporation of bioactive MPs or peptides into liposomes via CF synthesis can facilitate the development of proteoliposomal nanodelivery systems with improved circulation, increased targeting, and enhanced cellular delivery capacity. Moreover, by adapting lessons learned from natural delivery vehicles, novel bio-inspired proteoliposomes with enhanced delivery properties could be produced in CF systems. In this review, we first give an overview of CF synthesis with focus on enhancing protein expression in liposome-chaperoned CF systems. Furthermore, we intend to provide insight into harnessing CF-synthesized proteoliposomes for efficient therapeutic delivery.
Collapse
|
7
|
Hoffmann B, Löhr F, Laguerre A, Bernhard F, Dötsch V. Protein labeling strategies for liquid-state NMR spectroscopy using cell-free synthesis. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 105:1-22. [PMID: 29548364 DOI: 10.1016/j.pnmrs.2017.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 11/16/2017] [Indexed: 05/17/2023]
Abstract
Preparation of a protein sample for liquid-state nuclear magnetic resonance (NMR) spectroscopy analysis requires optimization of many parameters. This review describes labeling strategies for obtaining assignments of protein resonances. Particular emphasis is placed on the advantages of cell-free protein production, which enables exclusive labeling of the protein of interest, thereby simplifying downstream processing steps and increasing the availability of different labeling strategies for a target protein. Furthermore, proteins can be synthesized in milligram yields, and the open nature of the cell-free system allows the addition of stabilizers, scrambling inhibitors or hydrophobic solubilization environments directly during the protein synthesis, which is especially beneficial for membrane proteins. Selective amino acid labeling of the protein of interest, the possibility of addressing scrambling issues and avoiding the need for labile amino acid precursors have been key factors in enabling the introduction of new assignment strategies based on different labeling schemes as well as on new pulse sequences. Combinatorial selective labeling methods have been developed to reduce the number of protein samples necessary to achieve a complete backbone assignment. Furthermore, selective labeling helps to decrease spectral overlap and overcome size limitations for solution NMR analysis of larger complexes, oligomers, intrinsically disordered proteins and membrane proteins.
Collapse
Affiliation(s)
- Beate Hoffmann
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Frank Löhr
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Aisha Laguerre
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University, Max-von-Laue Str. 9, 60438 Frankfurt, Germany.
| |
Collapse
|
8
|
Foshag D, Henrich E, Hiller E, Schäfer M, Kerger C, Burger-Kentischer A, Diaz-Moreno I, García-Mauriño SM, Dötsch V, Rupp S, Bernhard F. The E. coli S30 lysate proteome: A prototype for cell-free protein production. N Biotechnol 2017; 40:245-260. [PMID: 28943390 DOI: 10.1016/j.nbt.2017.09.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/28/2017] [Accepted: 09/05/2017] [Indexed: 10/18/2022]
Abstract
Protein production using processed cell lysates is a core technology in synthetic biology and these systems are excellent to produce difficult toxins or membrane proteins. However, the composition of the central lysate of cell-free systems is still a "black box". Escherichia coli lysates are most productive for cell-free expression, yielding several mgs of protein per ml of reaction. Their preparation implies proteome fractionation, resulting in strongly biased and yet unknown lysate compositions. Many metabolic pathways are expected to be truncated or completely removed. The lack of knowledge of basic cell-free lysate proteomes is a major bottleneck for directed lysate engineering approaches as well as for assay design using non-purified reaction mixtures. This study is starting to close this gap by providing a blueprint of the S30 lysate proteome derived from the commonly used E. coli strain A19. S30 lysates are frequently used for cell-free protein production and represent the basis of most commercial E. coli cell-free expression systems. A fraction of 821 proteins was identified as the core proteome in S30 lysates, representing approximately a quarter of the known E. coli proteome. Its classification into functional groups relevant for transcription/translation, folding, stability and metabolic processes will build the framework for tailored cell-free reactions. As an example, we show that SOS response induction during cultivation results in tuned S30 lysate with better folding capacity, and improved solubility and activity of synthesized proteins. The presented data and protocols can serve as a platform for the generation of customized cell-free systems and product analysis.
Collapse
Affiliation(s)
- Daniel Foshag
- Institute for Interfacial Process Engineering and Plasma Technology, University of Stuttgart, Stuttgart, Germany
| | - Erik Henrich
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Ekkehard Hiller
- Fraunhofer Institute for Interfacial Engineering and Biotechnology, Stuttgart, Germany
| | - Miriam Schäfer
- Fraunhofer Institute for Interfacial Engineering and Biotechnology, Stuttgart, Germany
| | - Christian Kerger
- Fraunhofer Institute for Interfacial Engineering and Biotechnology, Stuttgart, Germany
| | | | - Irene Diaz-Moreno
- Instituto de Investigaciones Químicas (IIQ) - Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla - Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
| | - Sofía M García-Mauriño
- Instituto de Investigaciones Químicas (IIQ) - Centro de Investigaciones Científicas Isla de la Cartuja (cicCartuja), Universidad de Sevilla - Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany
| | - Steffen Rupp
- Fraunhofer Institute for Interfacial Engineering and Biotechnology, Stuttgart, Germany.
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt am Main, Germany.
| |
Collapse
|
9
|
From Gene to Function: Cell-Free Electrophysiological and Optical Analysis of Ion Pumps in Nanodiscs. Biophys J 2017; 113:1331-1341. [PMID: 28450130 DOI: 10.1016/j.bpj.2017.03.026] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 03/14/2017] [Accepted: 03/27/2017] [Indexed: 12/15/2022] Open
Abstract
Nanodiscs that hold a lipid bilayer surrounded by a boundary of scaffold proteins have emerged as a powerful tool for membrane protein solubilization and analysis. By combining nanodiscs and cell-free expression technologies, even completely detergent-free membrane protein characterization protocols can be designed. Nanodiscs are compatible with various techniques, and due to their bilayer environment and increased stability, they are often superior to detergent micelles or liposomes for membrane protein solubilization. However, transport assays in nanodiscs have not been conducted so far, due to limitations of the two-dimensional nature of nanodisc membranes that offers no compartmentalization. Here, we study Krokinobacter eikastus rhodopsin-2 (KR2), a microbial light-driven sodium or proton pump, with noncovalent mass-spectrometric, electrophysiological, and flash photolysis measurements after its cotranslational insertion into nanodiscs. We demonstrate the feasibility of adsorbing nanodiscs containing KR2 to an artificial bilayer. This allows us to record light-induced capacitive currents that reflect KR2's ion transport activity. The solid-supported membrane assay with nanodisc samples provides reliable control over the ionic condition and information of the relative ion activity of this promiscuous pump. Our strategy is complemented with flash photolysis data, where the lifetimes of different photointermediates were determined at different ionic conditions. The advantage of using identical samples to three complementary approaches allows for a comprehensive comparability. The cell-free synthesis in combination with nanodiscs provides a defined hydrophobic lipid environment minimizing the detergent dependence often seen in assays with membrane proteins. KR2 is a promising tool for optogenetics, thus directed engineering to modify ion selectivity can be highly beneficial. Our approach, using the fast generation of functional ion pumps incorporated into nanodiscs and their subsequent analysis by several biophysical techniques, can serve as a versatile screening and engineering platform. This may open new avenues for the study of ion pumps and similar electrogenic targets.
Collapse
|
10
|
Sugiki T, Kobayashi N, Fujiwara T. Modern Technologies of Solution Nuclear Magnetic Resonance Spectroscopy for Three-dimensional Structure Determination of Proteins Open Avenues for Life Scientists. Comput Struct Biotechnol J 2017; 15:328-339. [PMID: 28487762 PMCID: PMC5408130 DOI: 10.1016/j.csbj.2017.04.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/31/2017] [Accepted: 04/03/2017] [Indexed: 02/07/2023] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for structural studies of chemical compounds and biomolecules such as DNA and proteins. Since the NMR signal sensitively reflects the chemical environment and the dynamics of a nuclear spin, NMR experiments provide a wealth of structural and dynamic information about the molecule of interest at atomic resolution. In general, structural biology studies using NMR spectroscopy still require a reasonable understanding of the theory behind the technique and experience on how to recorded NMR data. Owing to the remarkable progress in the past decade, we can easily access suitable and popular analytical resources for NMR structure determination of proteins with high accuracy. Here, we describe the practical aspects, workflow and key points of modern NMR techniques used for solution structure determination of proteins. This review should aid NMR specialists aiming to develop new methods that accelerate the structure determination process, and open avenues for non-specialist and life scientists interested in using NMR spectroscopy to solve protein structures.
Collapse
Affiliation(s)
- Toshihiko Sugiki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Naohiro Kobayashi
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Toshimichi Fujiwara
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| |
Collapse
|
11
|
Henrich E, Peetz O, Hein C, Laguerre A, Hoffmann B, Hoffmann J, Dötsch V, Bernhard F, Morgner N. Analyzing native membrane protein assembly in nanodiscs by combined non-covalent mass spectrometry and synthetic biology. eLife 2017; 6. [PMID: 28067619 PMCID: PMC5291076 DOI: 10.7554/elife.20954] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 01/04/2017] [Indexed: 01/01/2023] Open
Abstract
Membrane proteins frequently assemble into higher order homo- or hetero-oligomers within their natural lipid environment. This complex formation can modulate their folding, activity as well as substrate selectivity. Non-disruptive methods avoiding critical steps, such as membrane disintegration, transfer into artificial environments or chemical modifications are therefore essential to analyze molecular mechanisms of native membrane protein assemblies. The combination of cell-free synthetic biology, nanodisc-technology and non-covalent mass spectrometry provides excellent synergies for the analysis of membrane protein oligomerization within defined membranes. We exemplify our strategy by oligomeric state characterization of various membrane proteins including ion channels, transporters and membrane-integrated enzymes assembling up to hexameric complexes. We further indicate a lipid-dependent dimer formation of MraY translocase correlating with the enzymatic activity. The detergent-free synthesis of membrane protein/nanodisc samples and the analysis by LILBID mass spectrometry provide a versatile platform for the analysis of membrane proteins in a native environment.
Collapse
Affiliation(s)
- Erik Henrich
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J W Goethe-University, Frankfurt am Main, Germany
| | - Oliver Peetz
- Institute of Physical and Theoretical Chemistry, J W Goethe-University, Frankfurt am Main, Germany
| | - Christopher Hein
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J W Goethe-University, Frankfurt am Main, Germany
| | - Aisha Laguerre
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J W Goethe-University, Frankfurt am Main, Germany
| | - Beate Hoffmann
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J W Goethe-University, Frankfurt am Main, Germany
| | - Jan Hoffmann
- Institute of Physical and Theoretical Chemistry, J W Goethe-University, Frankfurt am Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J W Goethe-University, Frankfurt am Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J W Goethe-University, Frankfurt am Main, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, J W Goethe-University, Frankfurt am Main, Germany
| |
Collapse
|
12
|
Abstract
Cell-free expression allows to synthesize membrane proteins in completely new formats that can relatively easily be customized for particular applications. Amphiphilic superstructures such as micelles, lipomicelles, or nanodiscs can be provided as nano-devices for the solubilization of membrane proteins. Defined empty bilayers in the form of nanodiscs offer native like environments for membrane proteins, supporting functional folding, proper oligomeric assembly as well as stability. Even very difficult and detergent-sensitive membrane proteins can be addressed by the combination of nanodisc technology with efficient cell-free expression systems as the direct co-translational insertion of nascent membrane proteins into supplied preassembled nanodiscs is possible. This chapter provides updated protocols for the synthesis of membrane proteins in presence of preassembled nanodiscs suitable for emerging applications such as screening of lipid effects on membrane protein function and the modulation of oligomeric complex formation.
Collapse
|
13
|
Waberer L, Henrich E, Peetz O, Morgner N, Dötsch V, Bernhard F, Volknandt W. The synaptic vesicle protein SV31 assembles into a dimer and transports Zn 2. J Neurochem 2016; 140:280-293. [PMID: 27917477 DOI: 10.1111/jnc.13886] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/25/2016] [Accepted: 10/29/2016] [Indexed: 01/20/2023]
Abstract
The integral synaptic vesicle protein SV31 has been shown to bind divalent cations. Here, we demonstrate that SV31 protein synthesized within a cell-free system binds Zn2+ and to a lower extent Ni2+ and Cu2+ ions. Expression with Zn2+ stabilized the protein and increased solubility. SV31 was preferentially monomeric in detergent and revealed specific binding of Zn2+ . When co-translationally inserted into defined nanodisc bilayers, SV31 assembled into dimeric complexes, resulting in increased binding of Zn2+ . Putative Zn2+ -binding motifs within SV31 comprise aspartic acid and histidine residues. Site-directed mutagenesis of two conserved aspartic acid residues leads to a potent decrease in Zn2+ binding but did not affect dimerization. Chemical modification of histidine residues abolished some of the Zn2+ -binding capacity. We demonstrate proton-dependent transport of Zn2+ as by accumulation of fluorescent FluoZin-1 inside of SV31-containing proteoliposomes. Transport activity has a Km value of 44.3 μM and required external Zn2+ and internal acidic pH. Our results demonstrate that the synaptic vesicle-integral protein SV31 functions as a proton-dependent Zn2+ transporter. SV31 may attribute specific and yet undiscovered functions to subsets of synapses.
Collapse
Affiliation(s)
- Lisa Waberer
- Institute of Cell Biology and Neuroscience, Goethe-University, Frankfurt am Main, Germany
| | - Erik Henrich
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, Goethe-University, Frankfurt am Main, Germany
| | - Oliver Peetz
- Institute of Physical and Theoretical Chemistry, Goethe-University, Frankfurt am Main, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, Goethe-University, Frankfurt am Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, Goethe-University, Frankfurt am Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, Goethe-University, Frankfurt am Main, Germany
| | - Walter Volknandt
- Institute of Cell Biology and Neuroscience, Goethe-University, Frankfurt am Main, Germany
| |
Collapse
|
14
|
Quast RB, Ballion B, Stech M, Sonnabend A, Varga BR, Wüstenhagen DA, Kele P, Schiller SM, Kubick S. Cell-free synthesis of functional human epidermal growth factor receptor: Investigation of ligand-independent dimerization in Sf21 microsomal membranes using non-canonical amino acids. Sci Rep 2016; 6:34048. [PMID: 27670253 PMCID: PMC5037433 DOI: 10.1038/srep34048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 09/07/2016] [Indexed: 12/15/2022] Open
Abstract
Cell-free protein synthesis systems represent versatile tools for the synthesis and modification of human membrane proteins. In particular, eukaryotic cell-free systems provide a promising platform for their structural and functional characterization. Here, we present the cell-free synthesis of functional human epidermal growth factor receptor and its vIII deletion mutant in a microsome-containing system derived from cultured Sf21 cells. We provide evidence for embedment of cell-free synthesized receptors into microsomal membranes and asparagine-linked glycosylation. Using the cricket paralysis virus internal ribosome entry site and a repetitive synthesis approach enrichment of receptors inside the microsomal fractions was facilitated thereby providing analytical amounts of functional protein. Receptor tyrosine kinase activation was demonstrated by monitoring receptor phosphorylation. Furthermore, an orthogonal cell-free translation system that provides the site-directed incorporation of p-azido-L-phenylalanine is characterized and applied to investigate receptor dimerization in the absence of a ligand by photo-affinity cross-linking. Finally, incorporated azides are used to generate stable covalently linked receptor dimers by strain-promoted cycloaddition using a novel linker system.
Collapse
Affiliation(s)
- Robert B Quast
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Biljana Ballion
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), School of Soft Matter Research, University of Freiburg, Albertstr. 19, D-79104 Freiburg, Germany.,Center for Biosystems Analysis (ZBSA), University of Freiburg, Habsburger Str. 49, D-79104 Freiburg, Germany
| | - Marlitt Stech
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Andrei Sonnabend
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Balázs R Varga
- Chemical Biology Research Group, Hungarian Academy of Sciences, CNS, IOC, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Doreen A Wüstenhagen
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Péter Kele
- Chemical Biology Research Group, Hungarian Academy of Sciences, CNS, IOC, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Stefan M Schiller
- Institute for Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, D-79104 Freiburg, Germany.,Freiburg Institute for Advanced Studies (FRIAS), School of Soft Matter Research, University of Freiburg, Albertstr. 19, D-79104 Freiburg, Germany.,Center for Biosystems Analysis (ZBSA), University of Freiburg, Habsburger Str. 49, D-79104 Freiburg, Germany
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| |
Collapse
|
15
|
Quast RB, Sonnabend A, Stech M, Wüstenhagen DA, Kubick S. High-yield cell-free synthesis of human EGFR by IRES-mediated protein translation in a continuous exchange cell-free reaction format. Sci Rep 2016; 6:30399. [PMID: 27456041 PMCID: PMC4960648 DOI: 10.1038/srep30399] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 07/01/2016] [Indexed: 01/18/2023] Open
Abstract
Cell-free protein synthesis systems derived from eukaryotic sources often provide comparatively low amounts of several μg per ml of de novo synthesized membrane protein. In order to overcome this, we herein demonstrate the high-yield cell-free synthesis of the human EGFR in a microsome-containing system derived from cultured Sf21 cells. Yields were increased more than 100-fold to more than 285 μg/ml by combination of IRES-mediated protein translation with a continuous exchange cell-free reaction format that allowed for prolonged reaction lifetimes exceeding 24 hours. In addition, an orthogonal cell-free translation system is presented that enabled the site-directed incorporation of p-Azido-L-phenylalanine by amber suppression. Functionality of cell-free synthesized receptor molecules is demonstrated by investigation of autophosphorylation activity in the absence of ligand and interaction with the cell-free synthesized adapter molecule Grb2.
Collapse
Affiliation(s)
- Robert B Quast
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Andrei Sonnabend
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Marlitt Stech
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Doreen A Wüstenhagen
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses (IZI-BB), Am Mühlenberg 13, D-14476 Potsdam, Germany
| |
Collapse
|
16
|
Intrinsic regulation of FIC-domain AMP-transferases by oligomerization and automodification. Proc Natl Acad Sci U S A 2016; 113:E529-37. [PMID: 26787847 DOI: 10.1073/pnas.1516930113] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Filamentation induced by cyclic AMP (FIC)-domain enzymes catalyze adenylylation or other posttranslational modifications of target proteins to control their function. Recently, we have shown that Fic enzymes are autoinhibited by an α-helix (αinh) that partly obstructs the active site. For the single-domain class III Fic proteins, the αinh is located at the C terminus and its deletion relieves autoinhibition. However, it has remained unclear how activation occurs naturally. Here, we show by structural, biophysical, and enzymatic analyses combined with in vivo data that the class III Fic protein NmFic from Neisseria meningitidis gets autoadenylylated in cis, thereby autonomously relieving autoinhibition and thus allowing subsequent adenylylation of its target, the DNA gyrase subunit GyrB. Furthermore, we show that NmFic activation is antagonized by tetramerization. The combination of autoadenylylation and tetramerization results in nonmonotonic concentration dependence of NmFic activity and a pronounced lag phase in the progress of target adenylylation. Bioinformatic analyses indicate that this elaborate dual-control mechanism is conserved throughout class III Fic proteins.
Collapse
|
17
|
Chi H, Wang X, Li J, Ren H, Huang F. Folding of newly translated membrane protein CCR5 is assisted by the chaperonin GroEL-GroES. Sci Rep 2015; 5:17037. [PMID: 26585937 PMCID: PMC4653635 DOI: 10.1038/srep17037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/23/2015] [Indexed: 01/20/2023] Open
Abstract
The in vitro folding of newly translated human CC chemokine receptor type 5
(CCR5), which belongs to the physiologically important family of G protein-coupled
receptors (GPCRs), has been studied in a cell-free system supplemented with the
surfactant Brij-35. The freshly synthesized CCR5 can spontaneously fold into its
biologically active state but only slowly and inefficiently. However, on addition of
the GroEL-GroES molecular chaperone system, the folding of the nascent CCR5 was
significantly enhanced, as was the structural stability and functional expression of
the soluble form of CCR5. The chaperonin GroEL was partially effective on its own,
but for maximum efficiency both the GroEL and its GroES lid were necessary. These
results are direct evidence for chaperone-assisted membrane protein folding and
therefore demonstrate that GroEL-GroES may be implicated in the folding of membrane
proteins.
Collapse
Affiliation(s)
- Haixia Chi
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Xiaoqiang Wang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Jiqiang Li
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Hao Ren
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| | - Fang Huang
- State Key Laboratory of Heavy Oil Processing and Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266580, P. R. China
| |
Collapse
|
18
|
Zemella A, Thoring L, Hoffmeister C, Kubick S. Cell-Free Protein Synthesis: Pros and Cons of Prokaryotic and Eukaryotic Systems. Chembiochem 2015; 16:2420-31. [PMID: 26478227 PMCID: PMC4676933 DOI: 10.1002/cbic.201500340] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 01/07/2023]
Abstract
From its start as a small-scale in vitro system to study fundamental translation processes, cell-free protein synthesis quickly rose to become a potent platform for the high-yield production of proteins. In contrast to classical in vivo protein expression, cell-free systems do not need time-consuming cloning steps, and the open nature provides easy manipulation of reaction conditions as well as high-throughput potential. Especially for the synthesis of difficult to express proteins, such as toxic and transmembrane proteins, cell-free systems are of enormous interest. The modification of the genetic code to incorporate non-canonical amino acids into the target protein in particular provides enormous potential in biotechnology and pharmaceutical research and is in the focus of many cell-free projects. Many sophisticated cell-free systems for manifold applications have been established. This review describes the recent advances in cell-free protein synthesis and details the expanding applications in this field.
Collapse
Affiliation(s)
- Anne Zemella
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses Potsdam-Golm (IZI-BB), Am Mühlenberg 13, 14476, Potsdam, Germany
| | - Lena Thoring
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses Potsdam-Golm (IZI-BB), Am Mühlenberg 13, 14476, Potsdam, Germany
| | - Christian Hoffmeister
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses Potsdam-Golm (IZI-BB), Am Mühlenberg 13, 14476, Potsdam, Germany
| | - Stefan Kubick
- Fraunhofer Institute for Cell Therapy and Immunology (IZI), Branch Bioanalytics and Bioprocesses Potsdam-Golm (IZI-BB), Am Mühlenberg 13, 14476, Potsdam, Germany.
| |
Collapse
|
19
|
LaGuerre A, Löhr F, Bernhard F, Dötsch V. Labeling of membrane proteins by cell-free expression. Methods Enzymol 2015; 565:367-88. [PMID: 26577739 DOI: 10.1016/bs.mie.2015.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The particular advantage of the cell-free reaction is that it allows a plethora of supplementation during protein expression and offers complete control over the available amino acid pool in view of concentration and composition. In combination with the fast and reliable production efficiencies of cell-free systems, the labeling and subsequent structural evaluation of very challenging targets, such as membrane proteins, comes into focus. We describe current methods for the isotopic labeling of cell-free synthesized membrane proteins and we review techniques available to the practitioner pursuing structural studies by nuclear magnetic resonance spectroscopy. Though isotopic labeling of individual amino acid types appears to be relatively straightforward, an ongoing critical issue in most labeling schemes for structural approaches is the selective substitution of deuterons for protons. While few options are available, the continuous refinement of labeling schemes in combination with improved pulse sequences and optimized instrumentation gives promising perspectives for extended applications in the structural evaluation of cell-free synthesized membrane.
Collapse
Affiliation(s)
- Aisha LaGuerre
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main, Germany.
| | - Frank Löhr
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main, Germany
| | - Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main, Germany
| | - Volker Dötsch
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main, Germany
| |
Collapse
|
20
|
Yu X, Bian X, Throop A, Song L, Moral LD, Park J, Seiler C, Fiacco M, Steel J, Hunter P, Saul J, Wang J, Qiu J, Pipas JM, LaBaer J. Exploration of panviral proteome: high-throughput cloning and functional implications in virus-host interactions. Am J Cancer Res 2014; 4:808-22. [PMID: 24955142 PMCID: PMC4063979 DOI: 10.7150/thno.8255] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 04/27/2014] [Indexed: 12/24/2022] Open
Abstract
Throughout the long history of virus-host co-evolution, viruses have developed delicate strategies to facilitate their invasion and replication of their genome, while silencing the host immune responses through various mechanisms. The systematic characterization of viral protein-host interactions would yield invaluable information in the understanding of viral invasion/evasion, diagnosis and therapeutic treatment of a viral infection, and mechanisms of host biology. With more than 2,000 viral genomes sequenced, only a small percent of them are well investigated. The access of these viral open reading frames (ORFs) in a flexible cloning format would greatly facilitate both in vitro and in vivo virus-host interaction studies. However, the overall progress of viral ORF cloning has been slow. To facilitate viral studies, we are releasing the initiation of our panviral proteome collection of 2,035 ORF clones from 830 viral genes in the Gateway® recombinational cloning system. Here, we demonstrate several uses of our viral collection including highly efficient production of viral proteins using human cell-free expression system in vitro, global identification of host targets for rubella virus using Nucleic Acid Programmable Protein Arrays (NAPPA) containing 10,000 unique human proteins, and detection of host serological responses using micro-fluidic multiplexed immunoassays. The studies presented here begin to elucidate host-viral protein interactions with our systemic utilization of viral ORFs, high-throughput cloning, and proteomic technologies. These valuable plasmid resources will be available to the research community to enable continued viral functional studies.
Collapse
|
21
|
Kalverda AP, Gowdy J, Thompson GS, Homans SW, Henderson PJF, Patching SG. TROSY NMR with a 52 kDa sugar transport protein and the binding of a small-molecule inhibitor. Mol Membr Biol 2014; 31:131-40. [DOI: 10.3109/09687688.2014.911980] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
22
|
Jackson K, Khnouf R, Fan ZH. Cell-free protein synthesis in microfluidic 96-well plates. Methods Mol Biol 2014; 1118:157-68. [PMID: 24395415 DOI: 10.1007/978-1-62703-782-2_10] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cell-free protein synthesis (CFPS) enables rapid protein expression for the structural and functional characterization of proteins. Implementation of CFPS in a microfluidic platform has additional benefits such as reduced reaction volumes and simultaneous expression of multiple proteins. Here, we describe a microfluidic device that is composed of 96 continuous-exchange cell-free protein expression units and produces a protein synthesis yield up to 87 times higher than a conventional batch system.
Collapse
Affiliation(s)
- Kirsten Jackson
- Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | | | | |
Collapse
|
23
|
Tumulka F, Roos C, Löhr F, Bock C, Bernhard F, Dötsch V, Abele R. Conformational stabilization of the membrane embedded targeting domain of the lysosomal peptide transporter TAPL for solution NMR. JOURNAL OF BIOMOLECULAR NMR 2013; 57:141-154. [PMID: 24013930 DOI: 10.1007/s10858-013-9774-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/21/2013] [Indexed: 06/02/2023]
Abstract
The ATP binding cassette transporter TAPL translocates cytosolic peptides into the lumen of lysosomes driven by the hydrolysis of ATP. Functionally, this transporter can be divided into coreTAPL, comprising the transport function, and an additional N-terminal transmembrane domain called TMD0, which is essential for lysosomal targeting and mediates the interaction with the lysosomal associated membrane proteins LAMP-1 and LAMP-2. To elucidate the structure of this unique domain, we developed protocols for the production of high quantities of cell-free expressed TMD0 by screening different N-terminal expression tags. Independently of the amino acid sequence, high expression was detected for AU-rich sequences in the first seven codons, decreasing the free energy of RNA secondary structure formation at translation initiation. Furthermore, avoiding NGG codons in the region of translation initiation demonstrated a positive effect on expression. For NMR studies, conditions were optimized for high solubilization efficiency, long-term stability, and high quality spectra. A most critical step was the careful exchange of the detergent used for solubilization by the detergent dihexanoylphosphatidylcholine. Several constructs of different size were tested in order to stabilize the fold of TMD0 as well as to reduce the conformation exchange. NMR spectra with sufficient resolution and homogeneity were finally obtained with a TMD0 derivative only modified by a C-terminal His10-tag and containing a codon optimized AT-rich sequence.
Collapse
Affiliation(s)
- Franz Tumulka
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438, Frankfurt am Main, Germany
| | | | | | | | | | | | | |
Collapse
|
24
|
Maslennikov I, Choe S. Advances in NMR structures of integral membrane proteins. Curr Opin Struct Biol 2013; 23:555-62. [PMID: 23721747 DOI: 10.1016/j.sbi.2013.05.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/26/2013] [Accepted: 05/01/2013] [Indexed: 01/26/2023]
Abstract
Integral membrane proteins (IMPs) play a central role in cell communication with the environment. Their structures are essential for our understanding of the molecular mechanisms of signaling and for drug design, yet they remain badly underrepresented in the protein structure databank. Solution NMR is, aside from X-ray crystallography, the major tool in structural biology. Here we review recently reported solution NMR structures of polytopic IMPs and discuss the new approaches, which were developed in the course of these studies to overcome barriers in the field. Advances in cell-free protein expression, combinatorial isotope labeling, resonance assignment, and collection of structural data greatly accelerated IMP structure determination by solution NMR. In addition, novel membrane-mimicking media made possible determination of solution NMR structures of IMPs in a native-like lipid environment.
Collapse
|
25
|
Bernhard F, Tozawa Y. Cell-free expression--making a mark. Curr Opin Struct Biol 2013; 23:374-80. [PMID: 23628286 DOI: 10.1016/j.sbi.2013.03.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 03/26/2013] [Accepted: 03/29/2013] [Indexed: 11/27/2022]
Abstract
Cell-free protein production opens new perspectives for the direct manipulation of expression compartments in combination with reduced complexity of physiological requirements. The technology is therefore in particular suitable for the general synthesis of difficult proteins including toxins and membrane proteins as well as for the analysis of their functional folding in artificial environments. A further key application of cell-free expression is the fast and economic labeling of proteins for structural and functional applications. Two extract sources, wheat embryos and Escherichia coli cells, are currently employed for the preparative scale cell-free production of proteins. Recent achievements in structural characterization include cell-free synthesized membrane proteins and even larger protein assemblies may become feasible.
Collapse
Affiliation(s)
- Frank Bernhard
- Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, Goethe University, Frankfurt am Main, Germany.
| | | |
Collapse
|
26
|
Emami S, Fan Y, Munro R, Ladizhansky V, Brown LS. Yeast-expressed human membrane protein aquaporin-1 yields excellent resolution of solid-state MAS NMR spectra. JOURNAL OF BIOMOLECULAR NMR 2013; 55:147-155. [PMID: 23344971 DOI: 10.1007/s10858-013-9710-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 01/15/2013] [Indexed: 06/01/2023]
Abstract
One of the biggest challenges in solid-state NMR studies of membrane proteins is to obtain a homogeneous natively folded sample giving high spectral resolution sufficient for structural studies. Eukaryotic membrane proteins are especially difficult and expensive targets in this respect. Methylotrophic yeast Pichia pastoris is a reliable producer of eukaryotic membrane proteins for crystallography and a promising economical source of isotopically labeled proteins for NMR. We show that eukaryotic membrane protein human aquaporin 1 can be doubly ((13)C/(15)N) isotopically labeled in this system and functionally reconstituted into phospholipids, giving excellent resolution of solid-state magic angle spinning NMR spectra.
Collapse
Affiliation(s)
- Sanaz Emami
- Departments of Physics, and Biophysics Interdepartmental Group, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | | | | | | | | |
Collapse
|
27
|
Ebersbach H, Geisse S. Antigen generation and display in therapeutic antibody drug discovery -- a neglected but critical player. Biotechnol J 2012; 7:1433-43. [PMID: 23139179 DOI: 10.1002/biot.201200066] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Revised: 08/26/2012] [Accepted: 09/25/2012] [Indexed: 01/17/2023]
Abstract
Disease intervention by targeting a critical pathway molecule through a blocking antibody or interference by therapeutic proteins is currently en vogue. Generation of blocking antibodies or therapeutic proteins inevitably requires the production of recombinant proteins or cell-based immunogens. Thus, one could call the antigen molecule the neglected player in antibody drug discovery. The variety of methods available for making recombinant proteins or recombinant cell lines that present the target on the cell surface is extensive. These need to be addressed in conjunction with biochemical and biophysical quality criteria and the experimental application intended. Fundamentally, successful production and isolation of monoclonal antibodies requires optimized antigen preparation and presentation to the immune host. This review summarizes the most important aspects of antigen generation and display, enabling logical decision making to give rise to potent high-affinity antibodies.
Collapse
Affiliation(s)
- Hilmar Ebersbach
- NBC/NT, Novartis Institutes for BioMedical Research, Basel, Switzerland.
| | | |
Collapse
|
28
|
Induction of humoral and cellular immune responses by antigen-expressing immunostimulatory liposomes. J Control Release 2012; 164:323-30. [PMID: 22940204 DOI: 10.1016/j.jconrel.2012.08.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 08/13/2012] [Accepted: 08/14/2012] [Indexed: 01/15/2023]
Abstract
Recently we have shown that liposomes can be used as artificial microbes for the production and delivery of DNA-encoded antigens. These so-called antigen-expressing immunostimulatory liposomes (AnExILs) were superior in inducing antigen-specific antibodies compared to conventional liposomal protein or DNA vaccines when tested in mice after i.m. immunization. In this study, we investigated the capacity of AnExILs to induce T-cell responses. By using a plasmid vector encoding a model antigen under control of both the prokaryotic T7 and the eukaryotic CMV promoter we hypothesized that antigen production could lead to CTL activation via two distinct routes: i. production of antigens inside the AnExILs with subsequent cross-presentation after processing by APCs and ii. endogenous production of antigens after AnExIL-mediated transfection of the pDNA. Although we were not able to demonstrate transfection-mediated expression of luc-NP in mice, i.m. injection of AnExILs producing luc-NP resulted in T-cell responses against the encoded NP epitope, as determined by tetramer staining. T-cell responses were comparable to the responses obtained after i.m. injection of naked pDNA. In order to find out whether CTL activation was caused by cross-presentation of the exogenous antigens produced inside AnExILs or by endogenous antigen production from transfection with the same pDNA source a second study was initiated in which the contribution of each of these effects could be separately determined. These results demonstrate that the observed T-cell responses were not exclusively caused by cross-presentation of the AnExIL-produced antigens alone, but were rather a combination of dose-dependent antigen cross-presentation and low levels of endogenous antigen production.
Collapse
|
29
|
Wang Y, Xu W, Kou X, Luo Y, Zhang Y, Ma B, Wang M, Huang K. Establishment and optimization of a wheat germ cell-free protein synthesis system and its application in venom kallikrein. Protein Expr Purif 2012; 84:173-80. [PMID: 22626528 DOI: 10.1016/j.pep.2012.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 12/18/2022]
Abstract
Wheat germ cell-free protein synthesis systems have the potential to synthesize functional proteins safely and with high accuracy, but the poor energy supply and the instability of mRNA templates reduce the productivity of this system, which restricts its applications. In this report, phosphocreatine and pyruvate were added to the system to supply ATP as a secondary energy source. After comparing the protein yield, we found that phosphocreatine is more suitable for use in the wheat germ cell-free protein synthesis system. To stabilize the mRNA template, the plasmid vector, SP6 RNA polymerase, and Cu(2+) were optimized, and a wheat germ cell-free protein synthesis system with high yield and speed was established. When plasmid vector (30 ng/μl), SP6 RNA polymerase (15 U), phosphocreatine (25 mM), and Cu(2+) (5 mM) were added to the system and incubated at 26°C for 16 h, the yield of venom kallikrein increased from 0.13 to 0.74 mg/ml. The specific activity of the recombinant protein was 1.3 U/mg, which is only slightly lower than the crude venom kallikrein (1.74 U/mg) due to the lack of the sugar chain. In this study, the yield of venom kallikrein was improved by optimizing the system, and a good foundation has been laid for industrial applications and for further studies.
Collapse
Affiliation(s)
- Yunpeng Wang
- School of Chemical Engineering and Technology, Tianjin University Tianjin 300072, China
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Kooijmans SAA, Vader P, van Dommelen SM, van Solinge WW, Schiffelers RM. Exosome mimetics: a novel class of drug delivery systems. Int J Nanomedicine 2012; 7:1525-41. [PMID: 22619510 PMCID: PMC3356169 DOI: 10.2147/ijn.s29661] [Citation(s) in RCA: 219] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The identification of extracellular phospholipid vesicles as conveyors of cellular information has created excitement in the field of drug delivery. Biological therapeutics, including short interfering RNA and recombinant proteins, are prone to degradation, have limited ability to cross biological membranes, and may elicit immune responses. Therefore, delivery systems for such drugs are under intensive investigation. Exploiting extracellular vesicles as carriers for biological therapeutics is a promising strategy to overcome these issues and to achieve efficient delivery to the cytosol of target cells. Exosomes are a well studied class of extracellular vesicles known to carry proteins and nucleic acids, making them especially suitable for such strategies. However, the considerable complexity and the related high chance of off-target effects of these carriers are major barriers for translation to the clinic. Given that it is well possible that not all components of exosomes are required for their proper functioning, an alternative strategy would be to mimic these vesicles synthetically. By assembly of liposomes harboring only crucial components of natural exosomes, functional exosome mimetics may be created. The low complexity and use of well characterized components strongly increase the pharmaceutical acceptability of such systems. However, exosomal components that would be required for the assembly of functional exosome mimetics remain to be identified. This review provides insights into the composition and functional properties of exosomes, and focuses on components which could be used to enhance the drug delivery properties of exosome mimetics.
Collapse
Affiliation(s)
- Sander A A Kooijmans
- Department of Clinical Chemistry and Haematology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | | | | |
Collapse
|
31
|
|
32
|
Ma Y, Münch D, Schneider T, Sahl HG, Bouhss A, Ghoshdastider U, Wang J, Dötsch V, Wang X, Bernhard F. Preparative scale cell-free production and quality optimization of MraY homologues in different expression modes. J Biol Chem 2011; 286:38844-53. [PMID: 21937437 PMCID: PMC3234709 DOI: 10.1074/jbc.m111.301085] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Indexed: 11/06/2022] Open
Abstract
MraY translocase catalyzes the first committed membrane-bound step of bacterial peptidoglycan synthesis leading to the formation of lipid I. The essential membrane protein therefore has a high potential as target for drug screening approaches to develop antibiotics against gram-positive as well as gram-negative bacteria. However, the production of large integral membrane proteins in conventional cellular expression systems is still very challenging. Cell-free expression technologies have been optimized in recent times for the production of membrane proteins in the presence of detergents (D-CF), lipids (L-CF), or as precipitates (P-CF). We report the development of preparative scale production protocols for the MraY homologues of Escherichia coli and Bacillus subtilis in all three cell-free expression modes followed by their subsequent quality evaluation. Although both proteins can be cell-free produced at comparable high levels, their requirements for optimal expression conditions differ markedly. B. subtilus MraY was stably folded in all three expression modes and showed highest translocase activities after P-CF production followed by defined treatment with detergents. In contrast, the E. coli MraY appears to be unstable after post- or cotranslational solubilization in detergent micelles. Expression kinetics and reducing conditions were identified as optimization parameters for the quality improvement of E. coli MraY. Most remarkably, in contrast to B. subtilis MraY the E. coli MraY has to be stabilized by lipids and only the production in the L-CF mode in the presence of preformed liposomes resulted in stable and translocase active protein samples.
Collapse
Affiliation(s)
- Yi Ma
- From the School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
- the Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main 60438, Germany
| | - Daniela Münch
- the Institute of Medical Microbiology, Immunology, and Parasitology, Pharmaceutical Microbiology Section, University of Bonn, Bonn 53105, Germany, and
| | - Tanja Schneider
- the Institute of Medical Microbiology, Immunology, and Parasitology, Pharmaceutical Microbiology Section, University of Bonn, Bonn 53105, Germany, and
| | - Hans-Georg Sahl
- the Institute of Medical Microbiology, Immunology, and Parasitology, Pharmaceutical Microbiology Section, University of Bonn, Bonn 53105, Germany, and
| | - Ahmed Bouhss
- the Institute of Biochemistry and Molecular and Cellular Biophysics, University Paris-Sud, UMR 8619 Orsay, France
| | - Umesh Ghoshdastider
- the Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main 60438, Germany
| | - Jufang Wang
- From the School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Volker Dötsch
- the Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main 60438, Germany
| | - Xiaoning Wang
- From the School of Bioscience and Bioengineering, South China University of Technology, Guangzhou 510006, China
| | - Frank Bernhard
- the Institute of Biophysical Chemistry, Centre for Biomolecular Magnetic Resonance, J.W. Goethe-University, Frankfurt-am-Main 60438, Germany
| |
Collapse
|
33
|
Affiliation(s)
- Simon G Patching
- Astbury Centre for Structural Molecular Biology and Institute of Membrane and Systems Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
| |
Collapse
|
34
|
Warschawski DE, Arnold AA, Beaugrand M, Gravel A, Chartrand É, Marcotte I. Choosing membrane mimetics for NMR structural studies of transmembrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1957-74. [DOI: 10.1016/j.bbamem.2011.03.016] [Citation(s) in RCA: 239] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 12/11/2022]
|
35
|
Rath P, Demange P, Saurel O, Tropis M, Daffé M, Dötsch V, Ghazi A, Bernhard F, Milon A. Functional expression of the PorAH channel from Corynebacterium glutamicum in cell-free expression systems: implications for the role of the naturally occurring mycolic acid modification. J Biol Chem 2011; 286:32525-32. [PMID: 21799011 DOI: 10.1074/jbc.m111.276956] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
PorA and PorH are two small membrane proteins from the outer membrane of Corynebacterium glutamicum, which have been shown to form heteromeric ion channels and to be post-translationally modified by mycolic acids. Any structural details of the channel could not be analyzed so far due to tremendous difficulties in the production of sufficient amounts of protein samples. Cell-free (CF) expression is a new and remarkably successful strategy for the production of membrane proteins for which toxicity, membrane targeting, and degradation are key issues. In addition, reaction conditions can easily be modified to modulate the quality of synthesized protein samples. We developed an efficient CF expression strategy to produce the channel subunits devoid of post-translational modifications. (15)N-labeled PorA and PorH samples were furthermore characterized by NMR and gave well resolved spectra, opening the way for structural studies. The comparison of ion channel activities of CF-expressed proteins with channels isolated from C. glutamicum gave clear insights on the influence of the mycolic acid modification of the two subunits on their functional properties.
Collapse
Affiliation(s)
- Parthasarathi Rath
- Centre National de la Recherche Scientifique, CNRS UMR 5089, Institut de Pharmacologie et de Biologie Structurale, 205 Route de Narbonne, Toulouse F-31077, Cedex 04, France
| | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Wheat-germ cell-free production of prion proteins for solid-state NMR structural studies. N Biotechnol 2011; 28:232-8. [DOI: 10.1016/j.nbt.2010.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Accepted: 06/28/2010] [Indexed: 12/14/2022]
|
37
|
Junge F, Haberstock S, Roos C, Stefer S, Proverbio D, Dötsch V, Bernhard F. Advances in cell-free protein synthesis for the functional and structural analysis of membrane proteins. N Biotechnol 2011; 28:262-71. [DOI: 10.1016/j.nbt.2010.07.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 06/28/2010] [Accepted: 07/04/2010] [Indexed: 11/25/2022]
|
38
|
Amidi M, de Raad M, Crommelin DJA, Hennink WE, Mastrobattista E. Antigen-expressing immunostimulatory liposomes as a genetically programmable synthetic vaccine. SYSTEMS AND SYNTHETIC BIOLOGY 2010; 5:21-31. [PMID: 21949673 PMCID: PMC3159695 DOI: 10.1007/s11693-010-9066-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Accepted: 10/07/2010] [Indexed: 01/13/2023]
Abstract
Liposomes are versatile (sub)micron-sized membrane vesicles that can be used for a variety of applications, including drug delivery and in vivo imaging but they also represent excellent models for artificial membranes or cells. Several studies have demonstrated that in vitro transcription and translation can take place inside liposomes to obtain compartmentalized production of functional proteins within the liposomes (Kita et al. in Chembiochem 9(15):2403–2410, 2008; Moritani et al.in FEBS J, 2010; Kuruma et al. in Methods Mol Biol 607:161–171, 2010; Murtas et al. in Biochem Biophys Res Commun 363(1):12–17, 2007; Sunami et al. in Anal Biochem 357(1):128–136, 2006; Ishikawa et al. in FEBS Lett 576(3):387–390, 2004; Oberholzer et al. in Biochem Biophys Res Commun 261(2):238–241, 1999). Such a minimal artificial cell-based model is ideal for synthetic biology based applications. In this study, we propose the use of liposomes as artificial microbes for vaccination. These artificial microbes can be genetically programmed to produce specific antigens at will. To show proof-of-concept for this artificial cell-based platform, a bacterial in vitro transcription and translation system together with a gene construct encoding the model antigen β-galactosidase were entrapped inside multilamellar liposomes. Vaccination studies in mice showed that such antigen-expressing immunostimulatory liposomes (AnExILs) elicited higher specific humoral immune responses against the produced antigen (β-galactosidase) than control vaccines (i.e. AnExILs without genetic input, liposomal β-galactosidase or pDNA encoding β-galactosidase). In conclusion, AnExILs present a new platform for DNA-based vaccines which combines antigen production, adjuvanticity and delivery in one system and which offer several advantages over existing vaccine formulations.
Collapse
Affiliation(s)
- Maryam Amidi
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, PO Box 80082, 3508 TB Utrecht, The Netherlands
| | | | | | | | | |
Collapse
|