51
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Ma P, Phillips-Jones MK. Membrane Sensor Histidine Kinases: Insights from Structural, Ligand and Inhibitor Studies of Full-Length Proteins and Signalling Domains for Antibiotic Discovery. Molecules 2021; 26:molecules26165110. [PMID: 34443697 PMCID: PMC8399564 DOI: 10.3390/molecules26165110] [Citation(s) in RCA: 6] [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: 07/13/2021] [Revised: 08/02/2021] [Accepted: 08/19/2021] [Indexed: 12/19/2022] Open
Abstract
There is an urgent need to find new antibacterial agents to combat bacterial infections, including agents that inhibit novel, hitherto unexploited targets in bacterial cells. Amongst novel targets are two-component signal transduction systems (TCSs) which are the main mechanism by which bacteria sense and respond to environmental changes. TCSs typically comprise a membrane-embedded sensory protein (the sensor histidine kinase, SHK) and a partner response regulator protein. Amongst promising targets within SHKs are those involved in environmental signal detection (useful for targeting specific SHKs) and the common themes of signal transmission across the membrane and propagation to catalytic domains (for targeting multiple SHKs). However, the nature of environmental signals for the vast majority of SHKs is still lacking, and there is a paucity of structural information based on full-length membrane-bound SHKs with and without ligand. Reasons for this lack of knowledge lie in the technical challenges associated with investigations of these relatively hydrophobic membrane proteins and the inherent flexibility of these multidomain proteins that reduces the chances of successful crystallisation for structural determination by X-ray crystallography. However, in recent years there has been an explosion of information published on (a) methodology for producing active forms of full-length detergent-, liposome- and nanodisc-solubilised membrane SHKs and their use in structural studies and identification of signalling ligands and inhibitors; and (b) mechanisms of signal sensing and transduction across the membrane obtained using sensory and transmembrane domains in isolation, which reveal some commonalities as well as unique features. Here we review the most recent advances in these areas and highlight those of potential use in future strategies for antibiotic discovery. This Review is part of a Special Issue entitled “Interactions of Bacterial Molecules with Their Ligands and Other Chemical Agents” edited by Mary K. Phillips-Jones.
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Affiliation(s)
- Pikyee Ma
- Laboratory of Biomolecular Research, Paul Scherrer Institute, CH-5232 Villigen, Switzerland;
| | - Mary K. Phillips-Jones
- National Centre for Macromolecular Hydrodynamics, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
- Correspondence:
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Reconstitution of Functional Integrin αIIbβ3 and Its Activation in Plasma Membrane-Mimetic Lipid Environments. MEMBRANES 2021; 11:membranes11070499. [PMID: 34209233 PMCID: PMC8304682 DOI: 10.3390/membranes11070499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/26/2021] [Accepted: 06/29/2021] [Indexed: 11/29/2022]
Abstract
The study of the platelet receptor integrin αIIbβ3 in a membrane-mimetic environment without interfering signalling pathways is crucial to understand protein structure and dynamics. Our understanding of this receptor and its sequential activation steps has been tremendously progressing using structural and reconstitution approaches in model membranes, such as liposomes or supported-lipid bilayers. For most αIIbβ3 reconstitution approaches, saturated short-chain lipids have been used, which is not reflecting the native platelet cell membrane composition. We report here on the reconstitution of label-free full-length αIIbβ3 in liposomes containing cholesterol, sphingomyelin, and unsaturated phosphatidylcholine mimicking the plasma membrane that formed supported-lipid bilayers for quartz-crystal microbalance with dissipation (QCM-D) experiments. We demonstrate the relevance of the lipid environment and its resulting physicochemical properties on integrin reconstitution efficiency and its conformational dynamics. We present here an approach to investigate αIIbβ3 in a biomimetic membrane system as a useful platform do dissect disease-relevant integrin mutations and effects on ligand binding in a lipid-specific context, which might be applicable for drug screening.
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53
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Current problems and future avenues in proteoliposome research. Biochem Soc Trans 2021; 48:1473-1492. [PMID: 32830854 DOI: 10.1042/bst20190966] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/11/2022]
Abstract
Membrane proteins (MPs) are the gatekeepers between different biological compartments separated by lipid bilayers. Being receptors, channels, transporters, or primary pumps, they fulfill a wide variety of cellular functions and their importance is reflected in the increasing number of drugs that target MPs. Functional studies of MPs within a native cellular context, however, is difficult due to the innate complexity of the densely packed membranes. Over the past decades, detergent-based extraction and purification of MPs and their reconstitution into lipid mimetic systems has been a very powerful tool to simplify the experimental system. In this review, we focus on proteoliposomes that have become an indispensable experimental system for enzymes with a vectorial function, including many of the here described energy transducing MPs. We first address long standing questions on the difficulty of successful reconstitution and controlled orientation of MPs into liposomes. A special emphasis is given on coreconstitution of several MPs into the same bilayer. Second, we discuss recent progress in the development of fluorescent dyes that offer sensitive detection with high temporal resolution. Finally, we briefly cover the use of giant unilamellar vesicles for the investigation of complex enzymatic cascades, a very promising experimental tool considering our increasing knowledge of the interplay of different cellular components.
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54
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Lee J, Song WJ. Folding of Circularly Permuted and Split Outer Membrane Protein F via Electrostatic Interactions with Terminal Residues. Biochemistry 2021; 60:1787-1796. [PMID: 34060805 DOI: 10.1021/acs.biochem.1c00195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Membrane proteins are essential targets in drug design, biosensing, and catalysis. In this study, we explored the folding of engineered outer membrane protein F (OmpF), an abundant and functional β-barrel protein expressed in Gram-negative bacteria. We carried out circular permutation, splitting and self-complementation, and point mutation. The folding efficiency and kinetic analyses demonstrated that the N- and C-terminal residues of OmpF played critical roles in folding via electrostatic interactions with lipid headgroups. Our results indicate that native porins without charged terminal residues may be tightly downregulated to retain the integrity of the outer membrane, and this modification may facilitate the insertion and folding of modified membrane proteins under in vitro and in vivo conditions for various applications.
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Affiliation(s)
- Jaewon Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Woon Ju Song
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul 08826, Republic of Korea
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55
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Rapid Production and Purification of Dye-Loaded Liposomes by Electrodialysis-Driven Depletion. MEMBRANES 2021; 11:membranes11060417. [PMID: 34072746 PMCID: PMC8228697 DOI: 10.3390/membranes11060417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/29/2021] [Accepted: 05/29/2021] [Indexed: 12/12/2022]
Abstract
Liposomes are spherical-shaped vesicles that enclose an aqueous milieu surrounded by bilayer or multilayer membranes formed by self-assembly of lipid molecules. They are intensively exploited as either model membranes for fundamental studies or as vehicles for delivery of active substances in vivo and in vitro. Irrespective of the method adopted for production of loaded liposomes, obtaining the final purified product is often achieved by employing multiple, time consuming steps. To alleviate this problem, we propose a simplified approach for concomitant production and purification of loaded liposomes by exploiting the Electrodialysis-Driven Depletion of charged molecules from solutions. Our investigations show that electrically-driven migration of charged detergent and dye molecules from solutions that include natural or synthetic lipid mixtures leads to rapid self-assembly of loaded, purified liposomes, as inferred from microscopy and fluorescence spectroscopy assessments. In addition, the same procedure was successfully applied for incorporating PEGylated lipids into the membranes for the purpose of enabling long-circulation times needed for potential in vivo applications. Dynamic Light Scattering analyses and comparison of electrically-formed liposomes with liposomes produced by sonication or extrusion suggest potential use for numerous in vitro and in vivo applications.
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56
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Guo X, Steinkühler J, Marin M, Li X, Lu W, Dimova R, Melikyan GB. Interferon-Induced Transmembrane Protein 3 Blocks Fusion of Diverse Enveloped Viruses by Altering Mechanical Properties of Cell Membranes. ACS NANO 2021; 15:8155-8170. [PMID: 33656312 PMCID: PMC8159881 DOI: 10.1021/acsnano.0c10567] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Interferon-induced transmembrane protein 3 (IFITM3) potently inhibits entry of diverse enveloped viruses by trapping the viral fusion at a hemifusion stage, but the underlying mechanism remains unclear. Here, we show that recombinant IFITM3 reconstituted into lipid vesicles induces negative membrane curvature and that this effect maps to its small amphipathic helix (AH). We demonstrate that AH (i) partitions into lipid-disordered domains where IAV fusion occurs, (ii) induces negative membrane curvature, and (iii) increases lipid order and membrane stiffness. These effects on membrane properties correlate with the fusion-inhibitory activity, as targeting the ectopically expressed AH peptide to the cytoplasmic leaflet of the cell plasma membrane diminishes IAV-cell surface fusion induced by exposure to acidic pH. Our results thus imply that IFITM3 inhibits the transition from hemifusion to full fusion by imposing an unfavorable membrane curvature and increasing the order and stiffness of the cytoplasmic leaflet of endosomal membranes. Our findings reveal a universal mechanism by which cells block entry of diverse enveloped viruses.
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Affiliation(s)
- Xiangyang Guo
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Jan Steinkühler
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Mariana Marin
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Xiang Li
- School of Pharmacy, Second Military Medical University, Shanghai, 200433, China
| | - Wuyuan Lu
- Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, Maryland 21201, United States
| | - Rumiana Dimova
- Max Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany
| | - Gregory B. Melikyan
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
- Children’s Healthcare of Atlanta, Atlanta, GA 30322, USA
- Corresponding author: Gregory B. Melikyan,
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57
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Rybenkov VV, Zgurskaya HI, Ganguly C, Leus IV, Zhang Z, Moniruzzaman M. The Whole Is Bigger than the Sum of Its Parts: Drug Transport in the Context of Two Membranes with Active Efflux. Chem Rev 2021; 121:5597-5631. [PMID: 33596653 PMCID: PMC8369882 DOI: 10.1021/acs.chemrev.0c01137] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell envelope plays a dual role in the life of bacteria by simultaneously protecting it from a hostile environment and facilitating access to beneficial molecules. At the heart of this ability lie the restrictive properties of the cellular membrane augmented by efflux transporters, which preclude intracellular penetration of most molecules except with the help of specialized uptake mediators. Recently, kinetic properties of the cell envelope came into focus driven on one hand by the urgent need in new antibiotics and, on the other hand, by experimental and theoretical advances in studies of transmembrane transport. A notable result from these studies is the development of a kinetic formalism that integrates the Michaelis-Menten behavior of individual transporters with transmembrane diffusion and offers a quantitative basis for the analysis of intracellular penetration of bioactive compounds. This review surveys key experimental and computational approaches to the investigation of transport by individual translocators and in whole cells, summarizes key findings from these studies and outlines implications for antibiotic discovery. Special emphasis is placed on Gram-negative bacteria, whose envelope contains two separate membranes. This feature sets these organisms apart from Gram-positive bacteria and eukaryotic cells by providing them with full benefits of the synergy between slow transmembrane diffusion and active efflux.
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Affiliation(s)
- Valentin V Rybenkov
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Chhandosee Ganguly
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Inga V Leus
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Zhen Zhang
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Mohammad Moniruzzaman
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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58
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Drew D, North RA, Nagarathinam K, Tanabe M. Structures and General Transport Mechanisms by the Major Facilitator Superfamily (MFS). Chem Rev 2021; 121:5289-5335. [PMID: 33886296 PMCID: PMC8154325 DOI: 10.1021/acs.chemrev.0c00983] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Indexed: 12/12/2022]
Abstract
The major facilitator superfamily (MFS) is the largest known superfamily of secondary active transporters. MFS transporters are responsible for transporting a broad spectrum of substrates, either down their concentration gradient or uphill using the energy stored in the electrochemical gradients. Over the last 10 years, more than a hundred different MFS transporter structures covering close to 40 members have provided an atomic framework for piecing together the molecular basis of their transport cycles. Here, we summarize the remarkable promiscuity of MFS members in terms of substrate recognition and proton coupling as well as the intricate gating mechanisms undergone in achieving substrate translocation. We outline studies that show how residues far from the substrate binding site can be just as important for fine-tuning substrate recognition and specificity as those residues directly coordinating the substrate, and how a number of MFS transporters have evolved to form unique complexes with chaperone and signaling functions. Through a deeper mechanistic description of glucose (GLUT) transporters and multidrug resistance (MDR) antiporters, we outline novel refinements to the rocker-switch alternating-access model, such as a latch mechanism for proton-coupled monosaccharide transport. We emphasize that a full understanding of transport requires an elucidation of MFS transporter dynamics, energy landscapes, and the determination of how rate transitions are modulated by lipids.
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Affiliation(s)
- David Drew
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Rachel A. North
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Kumar Nagarathinam
- Center
of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Lübeck, D-23538, Lübeck, Germany
| | - Mikio Tanabe
- Structural
Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801, Japan
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59
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Diederichs T, Tampé R. Single Cell-like Systems Reveal Active Unidirectional and Light-Controlled Transport by Nanomachineries. ACS NANO 2021; 15:6747-6755. [PMID: 33724767 PMCID: PMC8157534 DOI: 10.1021/acsnano.0c10139] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cellular life depends on transport and communication across membranes, which is emphasized by the fact that membrane proteins are prime drug targets. The cell-like environment of membrane proteins has gained increasing attention based on its important role in function and regulation. As a versatile scaffold for bottom-up synthetic biology and nanoscience, giant liposomes represent minimalistic models of living cells. Nevertheless, the incorporation of fragile multiprotein membrane complexes still remains a major challenge. Here, we report on an approach for the functional reconstitution of membrane assemblies exemplified by human and bacterial ATP-binding cassette (ABC) transporters. We reveal that these nanomachineries transport substrates unidirectionally against a steep concentration gradient. Active substrate transport can be spatiotemporally resolved in single cell-like compartments by light, enabling real-time tracking of substrate export and import in individual liposomes. This approach will help to construct delicate artificial cell-like systems.
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Affiliation(s)
- Tim Diederichs
- Institute of Biochemistry, Biocenter,
Goethe-University Frankfurt, Max-von Laue-Straße 9,
60438 Frankfurt a.M., Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter,
Goethe-University Frankfurt, Max-von Laue-Straße 9,
60438 Frankfurt a.M., Germany
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60
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Heath GR, Lin YC, Matin TR, Scheuring S. Structural dynamics of channels and transporters by high-speed atomic force microscopy. Methods Enzymol 2021; 652:127-159. [PMID: 34059280 DOI: 10.1016/bs.mie.2021.03.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Channels and transporters are vital for transmembrane transport of ions and solutes, and also of larger compounds such as lipids and macromolecules. Therefore, they are crucial in many biological processes such as sensing, signal transduction, and the regulation of the distribution of molecules. Dysfunctions of these membrane proteins are associated to numerous diseases, and their interaction with drugs is critical in medicine. Understanding the behavior of channels and transporters requires structural and dynamic information to decipher the molecular mechanisms underlying their function. High-Speed Atomic Force Microscopy (HS-AFM) now allows the study of single transmembrane channels and transporters in action under physiological conditions, i.e., at ambient temperature and pressure, in physiological buffer and in a membrane, and in a most direct, label-free manner. In this chapter, we discuss the HS-AFM sample preparation, application, and data analysis protocols to study the structural and conformational dynamics of membrane-embedded channels and transporters.
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Affiliation(s)
- George R Heath
- School of Physics and Astronomy, University of Leeds, Leeds, United Kingdom
| | - Yi-Chih Lin
- Weill Cornell Medicine, Department of Anesthesiology, New York, NY, United States
| | - Tina R Matin
- Weill Cornell Medicine, Department of Anesthesiology, New York, NY, United States
| | - Simon Scheuring
- Weill Cornell Medicine, Department of Anesthesiology, New York, NY, United States; Weill Cornell Medicine, Department of Physiology and Biophysics, New York, NY, United States.
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61
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Aggregation-related quenching of LHCII fluorescence in liposomes revealed by single-molecule spectroscopy. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 218:112174. [PMID: 33799009 DOI: 10.1016/j.jphotobiol.2021.112174] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/04/2021] [Accepted: 03/21/2021] [Indexed: 11/20/2022]
Abstract
Incorporation of membrane proteins into reconstituted lipid membranes is a common approach for studying their structure and function relationship in a native-like environment. In this work, we investigated fluorescence properties of liposome-reconstituted major light-harvesting complexes of plants (LHCII). By utilizing liposome labelling with the fluorescent dye molecules and single-molecule microscopy techniques, we were able to study truly liposome-reconstituted LHCII and compare them with bulk measurements and liposome-free LHCII aggregates bound to the surface. Our results showed that fluorescence lifetime obtained in bulk and in single liposome measurements were correlated. The fluorescence lifetimes of LHCII were shorter for liposome-free LHCII than for reconstituted LHCII. In the case of liposome-reconstituted LHCII, fluorescence lifetime showed dependence on the protein density reminiscent to concentration quenching. The dependence of fluorescence lifetime of LHCII on the liposome size was not significant. Our results demonstrated that fluorescence quenching can be induced by LHCII - LHCII interactions in reconstituted membranes, most likely occurring via the same mechanism as photoprotective non-photochemical quenching in vivo.
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62
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Shukla S, Baumgart T. Enzymatic trans-bilayer lipid transport: Mechanisms, efficiencies, slippage, and membrane curvature. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183534. [PMID: 33340491 PMCID: PMC8351443 DOI: 10.1016/j.bbamem.2020.183534] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/03/2020] [Accepted: 12/07/2020] [Indexed: 12/12/2022]
Abstract
The eukaryotic plasma membrane's lipid composition is found to be ubiquitously asymmetric comparing inner and outer leaflets. This membrane lipid asymmetry plays a crucial role in diverse cellular processes critical for cell survival. A specialized set of transmembrane proteins called translocases, or flippases, have evolved to maintain this membrane lipid asymmetry in an energy-dependent manner. One potential consequence of local variations in membrane lipid asymmetry is membrane remodeling, which is essential for cellular processes such as intracellular trafficking. Recently, there has been a surge in the identification and characterization of flippases, which has significantly advanced the understanding of their functional mechanisms. Furthermore, there are intriguing possibilities for a coupling between membrane curvature and flippase activity. In this review we highlight studies that link membrane shape and remodeling to differential stresses generated by the activity of lipid flippases with an emphasis on data obtained through model membrane systems. We review the common mechanistic models of flippase-mediated lipid flipping and discuss common techniques used to test lipid flippase activity. We then compare the existing data on lipid translocation rates by flippases and conclude with potential future directions for this field.
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Affiliation(s)
- Sankalp Shukla
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Tobias Baumgart
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, United States.
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63
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Grothe T, Nowak J, Jahn R, Walla PJ. Selected tools to visualize membrane interactions. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2021; 50:211-222. [PMID: 33787948 PMCID: PMC8071796 DOI: 10.1007/s00249-021-01516-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/19/2021] [Accepted: 03/08/2021] [Indexed: 11/28/2022]
Abstract
In the past decade, we developed various fluorescence-based methods for monitoring membrane fusion, membrane docking, distances between membranes, and membrane curvature. These tools were mainly developed using liposomes as model systems, which allows for the dissection of specific interactions mediated by, for example, fusion proteins. Here, we provide an overview of these methods, including two-photon fluorescence cross-correlation spectroscopy and intramembrane Förster energy transfer, with asymmetric labelling of inner and outer membrane leaflets and the calibrated use of transmembrane energy transfer to determine membrane distances below 10 nm. We discuss their application range and their limitations using examples from our work on protein-mediated vesicle docking and fusion.
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Affiliation(s)
- Tobias Grothe
- Laboratory of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, 37077, Göttingen, Germany
- Department of Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, University of Braunschweig, 38106, Braunschweig, Germany
| | - Julia Nowak
- Department of Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, University of Braunschweig, 38106, Braunschweig, Germany
| | - Reinhard Jahn
- Laboratory of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, 37077, Göttingen, Germany
| | - Peter Jomo Walla
- Laboratory of Neurobiology, Max-Planck-Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
- Department of Biophysical Chemistry, Institute for Physical and Theoretical Chemistry, University of Braunschweig, 38106, Braunschweig, Germany.
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64
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Hernández-Rocamora VM, Baranova N, Peters K, Breukink E, Loose M, Vollmer W. Real-time monitoring of peptidoglycan synthesis by membrane-reconstituted penicillin-binding proteins. eLife 2021; 10:61525. [PMID: 33625355 PMCID: PMC7943195 DOI: 10.7554/elife.61525] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 02/23/2021] [Indexed: 11/13/2022] Open
Abstract
Peptidoglycan is an essential component of the bacterial cell envelope that surrounds the cytoplasmic membrane to protect the cell from osmotic lysis. Important antibiotics such as β-lactams and glycopeptides target peptidoglycan biosynthesis. Class A penicillin-binding proteins (PBPs) are bifunctional membrane-bound peptidoglycan synthases that polymerize glycan chains and connect adjacent stem peptides by transpeptidation. How these enzymes work in their physiological membrane environment is poorly understood. Here, we developed a novel Förster resonance energy transfer-based assay to follow in real time both reactions of class A PBPs reconstituted in liposomes or supported lipid bilayers and applied this assay with PBP1B homologues from Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii in the presence or absence of their cognate lipoprotein activator. Our assay will allow unravelling the mechanisms of peptidoglycan synthesis in a lipid-bilayer environment and can be further developed to be used for high-throughput screening for new antimicrobials.
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Affiliation(s)
- Víctor M Hernández-Rocamora
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Natalia Baranova
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Katharina Peters
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Eefjan Breukink
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, University of Utrecht, Utrecht, Netherlands
| | - Martin Loose
- Institute for Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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65
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The Staphylococcus aureus CidA and LrgA Proteins Are Functional Holins Involved in the Transport of By-Products of Carbohydrate Metabolism. mBio 2021; 13:e0282721. [PMID: 35100878 PMCID: PMC8805020 DOI: 10.1128/mbio.02827-21] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Staphylococcus aureus cidABC and lrgAB operons encode members of a well-conserved family of proteins thought to be involved in programmed cell death (PCD). Based on the structural similarities that CidA and LrgA share with bacteriophage holins, we have hypothesized that these proteins function by forming pores within the cytoplasmic membrane. To test this, we utilized a "lysis cassette" system that demonstrated the abilities of the cidA and lrgA genes to support bacteriophage endolysin-induced cell lysis. Typical of holins, CidA- and LrgA-induced lysis was dependent on the coexpression of endolysin, consistent with the proposed holin-like functions of these proteins. In addition, the CidA and LrgA proteins were shown to localize to the surface of membrane vesicles and cause leakage of small molecules, providing direct evidence of their hole-forming potential. Consistent with recent reports demonstrating a role for the lrgAB homologues in other bacterial and plant species in the transport of by-products of carbohydrate metabolism, we also show that lrgAB is important for S. aureus to utilize pyruvate during microaerobic and anaerobic growth, by promoting the uptake of pyruvate under these conditions. Combined, these data reveal that the CidA and LrgA membrane proteins possess holin-like properties that play an important role in the transport of small by-products of carbohydrate metabolism. IMPORTANCE The Staphylococcus aureus cidABC and lrgAB operons represent the founding members of a large, highly conserved family of genes that span multiple kingdoms of life. Despite the fact that they have been shown to be involved in bacterial PCD, very little is known about the molecular/biochemical functions of the proteins they encode. The results presented in this study reveal that the cidA and lrgA genes encode proteins with bacteriophage holin-like functions, consistent with their roles in cell death. However, these studies also demonstrate that these operons are involved in the transport of small metabolic by-products of carbohydrate metabolism, suggesting an intriguing link between these two seemingly disparate processes.
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66
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Rationale for the Quantitative Reconstitution of Membrane Proteins into Proteoliposomes. Methods Mol Biol 2021. [PMID: 33582987 DOI: 10.1007/978-1-0716-0724-4_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Proteoliposome reconstitution is a method of choice for the investigation of membrane proteins as it allows their manipulation in the desired hydrophobic environment and allows one to tackle their study from both functional and structural points of view. Methods for their rapid and efficient reconstitution have been known for a long time but the quality and dispersity of the resulting suspensions is often overlooked. Here we describe our routine for the obtention of monodisperse populations of proteoliposomes as well as for the quantitation of protein per liposome.
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Wang N, Clark LD, Gao Y, Kozlov MM, Shemesh T, Rapoport TA. Mechanism of membrane-curvature generation by ER-tubule shaping proteins. Nat Commun 2021; 12:568. [PMID: 33495454 PMCID: PMC7835363 DOI: 10.1038/s41467-020-20625-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/07/2020] [Indexed: 12/15/2022] Open
Abstract
The endoplasmic reticulum (ER) network consists of tubules with high membrane curvature in cross-section, generated by the reticulons and REEPs. These proteins have two pairs of trans-membrane (TM) segments, followed by an amphipathic helix (APH), but how they induce curvature is poorly understood. Here, we show that REEPs form homodimers by interaction within the membrane. When overexpressed or reconstituted at high concentrations with phospholipids, REEPs cause extreme curvature through their TMs, generating lipoprotein particles instead of vesicles. The APH facilitates curvature generation, as its mutation prevents ER network formation of reconstituted proteoliposomes, and synthetic L- or D-amino acid peptides abolish ER network formation in Xenopus egg extracts. In Schizosaccharomyces japonicus, the APH is required for reticulon’s exclusive ER-tubule localization and restricted mobility. Thus, the TMs and APH cooperate to generate high membrane curvature. We propose that the formation of splayed REEP/reticulon dimers is responsible for ER tubule formation. The endoplasmic reticulum network consists of tubules with high membrane curvature in cross-section, generated by the reticulons and REEPs, but how they introduce curvature is poorly understood. Here authors show that REEPs form homodimers and use their amphipathic helix and trans-membrane segments to introduce high membrane curvature that can even lead to the formation of lipoprotein particles.
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Affiliation(s)
- Ning Wang
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Lindsay D Clark
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Yuan Gao
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Michael M Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Tom Shemesh
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Tom A Rapoport
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA.
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68
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Kielkopf CL, Bauer W, Urbatsch IL. Considerations for Membrane Protein Purification. Cold Spring Harb Protoc 2021; 2021:2021/1/pdb.top102285. [PMID: 33397781 DOI: 10.1101/pdb.top102285] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Isolating membrane proteins from their native cells while maintaining structural and functional integrity is challenging. Many detergents have been developed over the years that interact favorably with membrane proteins and mimic the physical properties of the lipid bilayer. Choosing the appropriate detergent is crucial for the successful extraction of a protein in its properly folded, active conformation.
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69
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Wipf D, Pfister C, Mounier A, Leborgne-Castel N, Frommer WB, Courty PE. Identification of Putative Interactors of Arabidopsis Sugar Transporters. TRENDS IN PLANT SCIENCE 2021; 26:13-22. [PMID: 33071187 DOI: 10.1016/j.tplants.2020.09.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/24/2020] [Accepted: 09/08/2020] [Indexed: 06/11/2023]
Abstract
Hexoses and disaccharides are the key carbon sources for essentially all physiological processes across kingdoms. In plants, sucrose, and in some cases raffinose and stachyose, are transported from the site of synthesis in leaves, the sources, to all other organs that depend on import, the sinks. Sugars also play key roles in interactions with beneficial and pathogenic microbes. Sugar transport is mediated by transport proteins that fall into super-families. Sugar transporter (ST) activity is tuned at different levels, including transcriptional and posttranslational levels. Understanding the ST interactome has a great potential to uncover important players in biologically and physiologically relevant processes, including, but not limited to Arabidopsis thaliana. Here, we combined ST interactions and coexpression studies to identify potentially relevant interaction networks.
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Affiliation(s)
- Daniel Wipf
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Carole Pfister
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Arnaud Mounier
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Nathalie Leborgne-Castel
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, 21000 Dijon, France
| | - Wolf B Frommer
- Institute for Molecular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf 40225, Germany; Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya 464-8601, Japan
| | - Pierre-Emmanuel Courty
- Agroécologie, AgroSup Dijon, CNRS, Université de Bourgogne, INRAE, Université de Bourgogne Franche-Comté, 21000 Dijon, France.
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70
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So PK. Hydrogen-Deuterium Exchange Mass Spectrometry for Probing Changes in Conformation and Dynamics of Proteins. Methods Mol Biol 2021; 2199:159-173. [PMID: 33125650 DOI: 10.1007/978-1-0716-0892-0_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hydrogen-deuterium exchange mass spectrometry (HDX-MS) is, nowadays, an increasingly important technique in studying protein conformation and dynamics. This technique possesses the advantages of low sample consumption, less limitation in protein size, and relatively simple experimental workflow. An HDX-MS experiment typically includes the steps of sample preparation, HDX reaction, quenching of HDX reaction, protease digestion, and LC-MS analysis. Although HDX-MS has been an established technique and automatic sample handling devices are commercially available nowadays, proper experimental conditions of each step are crucial for a successful HDX-MS experiment. This chapter is to provide a general guideline for each step in the HDX-MS workflow and highlight some precautions needed to be taken in order to acquire useful conformational and dynamic information.
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Affiliation(s)
- Pui-Kin So
- University Research Facility in Life Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
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71
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Schmid YRF, Scheller L, Buchmann S, Dittrich PS. Calcium-Mediated Liposome Fusion to Engineer Giant Lipid Vesicles with Cytosolic Proteins and Reconstituted Mammalian Proteins. ACTA ACUST UNITED AC 2020; 4:e2000153. [PMID: 33084207 DOI: 10.1002/adbi.202000153] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 09/25/2020] [Indexed: 12/16/2022]
Abstract
Giant unilamellar lipid vesicles (GUVs) are widely used as model membrane systems and provide an excellent basis to construct artificial cells. To construct more sophisticated artificial cells, proteins-in particular membrane proteins-need to be incorporated in GUVs. However, current methods for protein reconstitution have limited throughput or are not generally applicable for all proteins because they depend on detergent solubilization. This limitation is addressed here by introducing calcium-mediated membrane fusion to transfer proteins between negatively charged GUVs and cell-derived plasma membrane vesicles (CDVs), derived from HEK293T cells overexpressing a membrane receptor protein. Fusion conditions are optimized using large unilamellar vesicles and GUVs containing phosphatidylserines and fusogenic lipids. The approach is then applied to induce lipid mixing and subsequent transfer of the overexpressed membrane receptor from CDVs into GUVs. The membrane receptor is detected by immunofluorescence on GUVs that underwent lipid mixing with CDVs. Those GUVs also exhibit esterase activity because cytosolic esterases entrapped in the CDVs are transferred during membrane fusion. Thus, content mixing is demonstrated. Using CDVs circumvents the need to purify or solubilize proteins. Moreover, calcium-mediated fusion allows transfer of lipids, water-soluble and membrane bound proteins in one step, resulting in a semi-synthetic cell.
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Affiliation(s)
- Yannick R F Schmid
- Department of Biosystems Science and Engineering, Bioanalytics Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
| | - Leo Scheller
- Department of Biosystems Science and Engineering, Biotechnology and Bioengineering Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
| | - Sebastian Buchmann
- Department of Biosystems Science and Engineering, Bioanalytics Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
| | - Petra S Dittrich
- Department of Biosystems Science and Engineering, Bioanalytics Group, ETH Zürich, Mattenstrasse 26, Basel, CH-4058, Switzerland
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72
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Ueta T, Kojima K, Hino T, Shibata M, Nagano S, Sudo Y. Applicability of Styrene-Maleic Acid Copolymer for Two Microbial Rhodopsins, RxR and HsSRI. Biophys J 2020; 119:1760-1770. [PMID: 33086044 DOI: 10.1016/j.bpj.2020.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/03/2020] [Accepted: 09/21/2020] [Indexed: 12/20/2022] Open
Abstract
The membrane-embedded protein rhodopsin is widely produced in organisms as a photoreceptor showing a variety of light-dependent biological functions. To investigate its molecular features, rhodopsin is often extracted from cellular membrane lipids by a suitable detergent as "micelles." The extracted protein is purified by column chromatography and then is often reconstituted into "liposomes" by removal of the detergent. The styrene-maleic acid ("SMA") copolymer spontaneously forms nanostructures containing lipids without detergent. In this study, we applied SMA to characterize two microbial rhodopsins, a thermally stable rhodopsin, Rubrobacter xylanophilus rhodopsin (RxR), and an unstable one, Halobacterium salinarum sensory rhodopsin I (HsSRI), and evaluated their physicochemical properties in SMA lipid particles compared with rhodopsins in micelles and in liposomes. Those two rhodopsins were produced in Escherichia coli cells and were successfully extracted from the membrane by the addition of SMA (5 w/v %) without losing their visible color. Analysis by dynamic light scattering revealed that RxR in SMA lipid particles (RxR-SMA) formed a discoidal structure with a diameter of 54 nm, which was 10 times smaller than RxR in phosphatidylcholine liposomes. The small particle size of RxR-SMA allowed us to obtain scattering-less visible spectra with a high signal-to-noise ratio similar to RxR in detergent micelles composed of n-dodecyl-β-D-maltoside. High-speed atomic force microscopy revealed that a single particle contained an average of 4.1 trimers of RxR (12.3 monomers). In addition, RxR-SMA showed a fast cyclic photoreaction (k = 13 s-1) comparable with RxR in phosphatidylcholine liposomes (17 s-1) but not to RxR in detergent micelles composed of n-dodecyl-β-D-maltoside (0.59 s-1). By taking advantage of SMA, we determined the dissociation constant (Kd) of chloride for HsSRI as 34 mM. From these results, we conclude that SMA is a useful molecule forming a membrane-mimicking assembly for microbial rhodopsins having the advantages of detergents and liposomes.
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Affiliation(s)
- Tetsuya Ueta
- Dentistry and Pharmaceutical Sciences, Graduate School of Medicine, Okayama University, Okayama, Japan
| | - Keiichi Kojima
- Dentistry and Pharmaceutical Sciences, Graduate School of Medicine, Okayama University, Okayama, Japan
| | - Tomoya Hino
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori, Japan; Center for Research on Green Sustainable Chemistry, Tottori University, Tottori, Japan
| | - Mikihiro Shibata
- Nano Life Science Institute (WPI-NanoLSI), and High-Speed AFM for Biological Application Unit, Institute for Frontier Science Initiative, Kanazawa University, Kakuma, Kanazawa, Japan
| | - Shingo Nagano
- Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, Tottori, Japan; Center for Research on Green Sustainable Chemistry, Tottori University, Tottori, Japan
| | - Yuki Sudo
- Dentistry and Pharmaceutical Sciences, Graduate School of Medicine, Okayama University, Okayama, Japan.
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73
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Porter CJ, Werber JR, Zhong M, Wilson CJ, Elimelech M. Pathways and Challenges for Biomimetic Desalination Membranes with Sub-Nanometer Channels. ACS NANO 2020; 14:10894-10916. [PMID: 32886487 DOI: 10.1021/acsnano.0c05753] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transmembrane protein channels, including ion channels and aquaporins that are responsible for fast and selective transport of water, have inspired membrane scientists to exploit and mimic their performance in membrane technologies. These biomimetic membranes comprise discrete nanochannels aligned within amphiphilic matrices on a robust support. While biological components have been used directly, extensive work has also been conducted to produce stable synthetic mimics of protein channels and lipid bilayers. However, the experimental performance of biomimetic membranes remains far below that of biological membranes. In this review, we critically assess the status and potential of biomimetic desalination membranes. We first review channel chemistries and their transport behavior, identifying key characteristics to optimize water permeability and salt rejection. We compare various channel types within an industrial context, considering transport performance, processability, and stability. Through a re-examination of previous vesicular stopped-flow studies, we demonstrate that incorrect permeability equations result in an overestimation of the water permeability of nanochannels. We find in particular that the most optimized aquaporin-bearing bilayer had a pure water permeability of 2.1 L m-2 h-1 bar-1, which is comparable to that of current state-of-the-art polymeric desalination membranes. Through a quantitative assessment of biomimetic membrane formats, we analytically show that formats incorporating intact vesicles offer minimal benefit, whereas planar biomimetic selective layers could allow for dramatically improved salt rejections. We then show that the persistence of nanoscale defects explains observed subpar performance. We conclude with a discussion on optimal strategies for minimizing these defects, which could enable breakthrough performance.
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Affiliation(s)
- Cassandra J Porter
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Jay R Werber
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mingjiang Zhong
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Corey J Wilson
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Menachem Elimelech
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
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Mirzaei Garakani T, Sauer DF, Mertens MAS, Lazar J, Gehrmann J, Arlt M, Schiffels J, Schnakenberg U, Okuda J, Schwaneberg U. FhuA–Grubbs–Hoveyda Biohybrid Catalyst Embedded in a Polymer Film Enables Catalysis in Neat Substrates. ACS Catal 2020. [DOI: 10.1021/acscatal.0c03055] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Daniel F. Sauer
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | | | - Jaroslav Lazar
- Institute of Materials in Electrical Engineering 1, RWTH Aachen University, Sommerfeldstr. 24, 52074 Aachen, Germany
| | - Julia Gehrmann
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Marcus Arlt
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Johannes Schiffels
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
| | - Uwe Schnakenberg
- Institute of Materials in Electrical Engineering 1, RWTH Aachen University, Sommerfeldstr. 24, 52074 Aachen, Germany
| | - Jun Okuda
- Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany
| | - Ulrich Schwaneberg
- Institute of Biotechnology, RWTH Aachen University, Worringerweg 3, 52074 Aachen, Germany
- DWI—Leibniz Institute for Interactive Materials, Forckenbeckstr. 50, D-52056 Aachen, Germany
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75
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Yao X, Fan X, Yan N. Cryo-EM analysis of a membrane protein embedded in the liposome. Proc Natl Acad Sci U S A 2020; 117:18497-18503. [PMID: 32680969 PMCID: PMC7414195 DOI: 10.1073/pnas.2009385117] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Membrane proteins (MPs) used to be the most difficult targets for structural biology when X-ray crystallography was the mainstream approach. With the resolution revolution of single-particle electron cryo-microscopy (cryo-EM), rapid progress has been made for structural elucidation of isolated MPs. The next challenge is to preserve the electrochemical gradients and membrane curvature for a comprehensive structural elucidation of MPs that rely on these chemical and physical properties for their biological functions. Toward this goal, here we present a convenient workflow for cryo-EM structural analysis of MPs embedded in liposomes, using the well-characterized AcrB as a prototype. Combining optimized proteoliposome isolation, cryo-sample preparation on graphene grids, and an efficient particle selection strategy, the three-dimensional (3D) reconstruction of AcrB embedded in liposomes was obtained at 3.9 Å resolution. The conformation of the homotrimeric AcrB remains the same when the surrounding membranes display different curvatures. Our approach, which can be widely applied to cryo-EM analysis of MPs with distinctive soluble domains, lays out the foundation for cryo-EM analysis of integral or peripheral MPs whose functions are affected by transmembrane electrochemical gradients or/and membrane curvatures.
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Affiliation(s)
- Xia Yao
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Xiao Fan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | - Nieng Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
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76
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Kleineberg C, Wölfer C, Abbasnia A, Pischel D, Bednarz C, Ivanov I, Heitkamp T, Börsch M, Sundmacher K, Vidaković‐Koch T. Light-Driven ATP Regeneration in Diblock/Grafted Hybrid Vesicles. Chembiochem 2020; 21:2149-2160. [PMID: 32187828 PMCID: PMC7496644 DOI: 10.1002/cbic.201900774] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/02/2020] [Indexed: 01/19/2023]
Abstract
Light-driven ATP regeneration systems combining ATP synthase and bacteriorhodopsin have been proposed as an energy supply in the field of synthetic biology. Energy is required to power biochemical reactions within artificially created reaction compartments like protocells, which are typically based on either lipid or polymer membranes. The insertion of membrane proteins into different hybrid membranes is delicate, and studies comparing these systems with liposomes are needed. Here we present a detailed study of membrane protein functionality in different hybrid compartments made of graft polymer PDMS-g-PEO and diblock copolymer PBd-PEO. Activity of more than 90 % in lipid/polymer-based hybrid vesicles could prove an excellent biocompatibility. A significant enhancement of long-term stability (80 % remaining activity after 42 days) could be demonstrated in polymer/polymer-based hybrids.
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Affiliation(s)
- Christin Kleineberg
- Max Planck Institute for Dynamics of Complex Technical Systems Process Systems EngineeringSandtorstraße 139106MagdeburgGermany
| | - Christian Wölfer
- Max Planck Institute for Dynamics of Complex Technical Systems Process Systems EngineeringSandtorstraße 139106MagdeburgGermany
| | - Amirhossein Abbasnia
- Max Planck Institute for Dynamics of Complex Technical Systems Process Systems EngineeringSandtorstraße 139106MagdeburgGermany
| | - Dennis Pischel
- Otto von Guericke UniversityProcess Systems EngineeringUniversitätsplatz 239106MagdeburgGermany
| | - Claudia Bednarz
- Max Planck Institute for Dynamics of Complex Technical Systems Process Systems EngineeringSandtorstraße 139106MagdeburgGermany
| | - Ivan Ivanov
- Max Planck Institute for Dynamics of Complex Technical Systems Process Systems EngineeringSandtorstraße 139106MagdeburgGermany
| | - Thomas Heitkamp
- Jena University Hospital; Single-Molecule Microscopy GroupNonnenplan 2–407743JenaGermany
| | - Michael Börsch
- Jena University Hospital; Single-Molecule Microscopy GroupNonnenplan 2–407743JenaGermany
| | - Kai Sundmacher
- Max Planck Institute for Dynamics of Complex Technical Systems Process Systems EngineeringSandtorstraße 139106MagdeburgGermany
- Otto von Guericke UniversityProcess Systems EngineeringUniversitätsplatz 239106MagdeburgGermany
| | - Tanja Vidaković‐Koch
- Max Planck Institute for Dynamics of Complex Technical Systems Process Systems EngineeringSandtorstraße 139106MagdeburgGermany
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77
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Schmidt CC, Vasic V, Stein A. Doa10 is a membrane protein retrotranslocase in ER-associated protein degradation. eLife 2020; 9:56945. [PMID: 32588820 PMCID: PMC7319771 DOI: 10.7554/elife.56945] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 05/28/2020] [Indexed: 12/17/2022] Open
Abstract
In endoplasmic reticulum-associated protein degradation (ERAD), membrane proteins are ubiquitinated, extracted from the membrane, and degraded by the proteasome. The cytosolic ATPase Cdc48 drives extraction by pulling on polyubiquitinated substrates. How hydrophobic transmembrane (TM) segments are moved from the phospholipid bilayer into cytosol, often together with hydrophilic and folded ER luminal protein parts, is not known. Using a reconstituted system with purified proteins from Saccharomyces cerevisiae, we show that the ubiquitin ligase Doa10 (Teb-4/MARCH6 in animals) is a retrotranslocase that facilitates membrane protein extraction. A substrate’s TM segment interacts with the membrane-embedded domain of Doa10 and then passively moves into the aqueous phase. Luminal substrate segments cross the membrane in an unfolded state. Their unfolding occurs on the luminal side of the membrane by cytoplasmic Cdc48 action. Our results reveal how a membrane-bound retrotranslocase cooperates with the Cdc48 ATPase in membrane protein extraction. The inside of a cell contains many different compartments called organelles, which are separated by membranes. Each organelle is composed of a unique set of proteins and performs specific roles in the cell. The endoplasmic reticulum, or ER for short, is an organelle where many proteins are produced. Most of these proteins are then released from the cell or sorted to other organelles. The ER has a strict quality control system that ensures any faulty proteins are quickly marked for the cell to destroy. However, the destruction process itself does not happen in the ER, so faulty proteins first need to leave this organelle. This is achieved by a group of proteins known as endoplasmic reticulum-associated protein degradation machinery (or ERAD for short). To extract a faulty protein from the ER, proteins of the ER and outside the ER cooperate. First, an ERAD protein called Doa10 attaches a small protein tag called ubiquitin to the faulty proteins to mark them for destruction. Then, outside of the ER, a protein called Cdc48 ‘grabs’ the ubiquitin tag and pulls. But that is only part of the story. Many of the proteins made by the ER have tethers that anchor them firmly to the membrane, making them much harder to remove. To get a better idea of how the extraction works, Schmidt et al. rebuilt the ERAD machinery in a test tube. This involved purifying proteins from yeast and inserting them into artificial membranes, allowing closer study of each part of the process. This revealed that attaching ubiquitin tags to faulty proteins is only one part of Doa10's role; it also participates in the extraction itself. Part of Doa10 resides within the membrane, and this ‘membrane-spanning domain’ can interact with faulty proteins, loosening their membrane anchors. At the same time, Cdc48 pulls from the outside. This pulling force causes the faulty proteins to unfold, allowing them to pass through the membrane. Given these findings, the next step is to find out exactly how Doa10 works by looking at its three-dimensional structure. This could have implications not only for the study of ERAD, but of similar quality control processes in other organelles too. A build-up of faulty proteins can cause diseases like neurodegeneration, so understanding how cells remove faulty proteins could help future medical research.
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Affiliation(s)
- Claudia C Schmidt
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Vedran Vasic
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Alexander Stein
- Research Group Membrane Protein Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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78
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Zhao J, Hu J. Self-Association of Purified Reconstituted ER Luminal Spacer Climp63. Front Cell Dev Biol 2020; 8:500. [PMID: 32612999 PMCID: PMC7308479 DOI: 10.3389/fcell.2020.00500] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 05/25/2020] [Indexed: 01/15/2023] Open
Abstract
Membranes of the endoplasmic reticulum (ER) are shaped into cisternal sheets and cylindrical tubules. How ER sheets are generated and maintained is not clear. ER membrane protein Climp63 is enriched in sheets and routinely used as a marker of this structure. The luminal domain (LD) of Climp63 is predicted to be highly helical, and it may form bridges between parallel membranes, regulating the abundance and width of ER sheets. Here, we purified the LD and full-length (FL) Climp63 to analyze their homotypic interactions. The N-terminal tagged LD formed low-order oligomers in solution, but was extremely aggregation-prone when the GST tag was removed. Purified FL Climp63 formed detectable but moderate interactions with both the FL protein and the LD. When Climp63 was reconstituted into proteoliposomes with its LD facing out, the homotypic interactions were retained and could be competed by soluble LD, though vesicle clustering was not observed. These results demonstrate a direct self-association of Climp63, supporting its role as an ER luminal spacer.
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Affiliation(s)
- Jinghua Zhao
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Junjie Hu
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
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79
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Analysis of Mitochondrial Membrane Fusion GTPase OPA1 Expressed by the Silkworm Expression System. Methods Mol Biol 2020. [PMID: 32529367 DOI: 10.1007/978-1-0716-0676-6_9] [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: 11/14/2023]
Abstract
Mitochondria are highly dynamic organelles, which move and fuse to regulate their shape, size, and fundamental function. The dynamin-related GTPases play a critical role in mitochondrial membrane fusion. In vitro reconstitution of membrane fusion using recombinant proteins and model membranes is quite useful in elucidating the molecular mechanisms underlying membrane fusion and to identify the essential elements involved in fusion. However, only a few reconstituting approaches have been reported for mitochondrial fusion machinery due to the difficulty of preparing active recombinant mitochondrial fusion GTPases. Recently, we succeeded in preparing a sufficient amount of recombinant OPA1 involved in mitochondrial inner membrane fusion using a BmNPV bacmid-silkworm expression system. In this chapter, we describe the method for the expression and purification of a membrane-anchored form of OPA1 and liposome-based in vitro reconstitution of membrane fusion.
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80
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Ramadan S, Tammam SN, Shetab Boushehri MA, Breitinger HG, Breitinger U, Mansour S, Lamprecht A. Liposomal delivery of functional transmembrane ion channels into the cell membranes of target cells; a potential approach for the treatment of channelopathies. Int J Biol Macromol 2020; 153:1080-1089. [DOI: 10.1016/j.ijbiomac.2019.10.238] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 02/07/2023]
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81
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Buddingh' BC, Elzinga J, van Hest JCM. Intercellular communication between artificial cells by allosteric amplification of a molecular signal. Nat Commun 2020; 11:1652. [PMID: 32246068 PMCID: PMC7125153 DOI: 10.1038/s41467-020-15482-8] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 03/13/2020] [Indexed: 11/13/2022] Open
Abstract
Multicellular organisms rely on intercellular communication to coordinate the behaviour of individual cells, which enables their differentiation and hierarchical organization. Various cell mimics have been developed to establish fundamental engineering principles for the construction of artificial cells displaying cell-like organization, behaviour and complexity. However, collective phenomena, although of great importance for a better understanding of life-like behaviour, are underexplored. Here, we construct collectives of giant vesicles that can communicate with each other through diffusing chemical signals that are recognized and processed by synthetic enzymatic cascades. Similar to biological cells, the Receiver vesicles can transduce a weak signal originating from Sender vesicles into a strong response by virtue of a signal amplification step, which facilitates the propagation of signals over long distances within the artificial cell consortia. This design advances the development of interconnected artificial cells that can exchange metabolic and positional information to coordinate their higher-order organization.
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Affiliation(s)
- Bastiaan C Buddingh'
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven, the Netherlands
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven, the Netherlands
| | - Janneke Elzinga
- Radboud University, PO Box 9102, 6500 HC, Nijmegen, the Netherlands
| | - Jan C M van Hest
- Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven, the Netherlands.
- Institute for Complex Molecular Systems, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven, the Netherlands.
- Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven, the Netherlands.
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82
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Gardill B, Huang J, Tu L, Van Petegem F, Oxenoid K, Thomson CA. Nanodisc technology facilitates identification of monoclonal antibodies targeting multi-pass membrane proteins. Sci Rep 2020; 10:1130. [PMID: 31980674 PMCID: PMC6981118 DOI: 10.1038/s41598-020-58002-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 01/08/2020] [Indexed: 12/31/2022] Open
Abstract
Multi-pass membrane proteins are important targets of biologic medicines. Given the inherent difficulties in working with membrane proteins, we sought to investigate the utility of membrane scaffold protein nanodiscs as a means of solubilizing membrane proteins to aid antibody discovery. Using a model multi-pass membrane protein, we demonstrate how incorporation of a multi-pass membrane protein into nanodiscs can be used in flow cytometry to identify antigen-specific hybridoma. The use of target protein-loaded nanodiscs to sort individual hybridoma early in the screening process can reduce the time required to identify antibodies against multi-pass membrane proteins.
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Affiliation(s)
- Bernd Gardill
- Amgen Research, Biologic Discovery, Burnaby, BC, Canada.,The University of British Columbia, Department of Biochemistry and Molecular Biology, Life Sciences Institute, Vancouver, BC, Canada.,Amgen Research, Munich, Germany
| | - Jerry Huang
- Amgen Research, Biologic Discovery, Burnaby, BC, Canada
| | - Lawrence Tu
- Amgen Research, Biologic Discovery, Burnaby, BC, Canada
| | - Filip Van Petegem
- The University of British Columbia, Department of Biochemistry and Molecular Biology, Life Sciences Institute, Vancouver, BC, Canada
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83
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Barniol-Xicota M, Verhelst SHL. Isolation of intramembrane proteases in membrane-like environments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183193. [PMID: 31945321 DOI: 10.1016/j.bbamem.2020.183193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/07/2020] [Accepted: 01/10/2020] [Indexed: 12/24/2022]
Abstract
Intramembrane proteases (IMPs) are proteolytic enzymes embedded in the lipid bilayer, where they cleave transmembrane substrates. The importance of IMPs relies on their role in a wide variety of cellular processes and diseases. In order to study the activity and function of IMPs, their purified form is often desired. The production of pure and active IMPs has proven to be a challenging task. This process unavoidably requires the use of solubilizing agents that will, to some extent, alter the native environment of these proteases. In this review we present the current solubilization and reconstitution techniques that have been applied to IMPs. In addition, we describe how these techniques had an influence on the activity and structural studies of IMPs, focusing on rhomboid proteases and γ-secretase.
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Affiliation(s)
- Marta Barniol-Xicota
- KU Leuven, Department of Cellular and Molecular Medicine, Laboratory of Chemical Biology, Herestraat 49, Box 802, B-3000, Belgium.
| | - Steven H L Verhelst
- KU Leuven, Department of Cellular and Molecular Medicine, Laboratory of Chemical Biology, Herestraat 49, Box 802, B-3000, Belgium; Leibniz Institute for Analytical Sciences, ISAS, e.V., Otto-Hahn-Str. 6b, 44227 Dortmund, Germany.
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84
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Tietz S, Leuenberger M, Höhner R, Olson AH, Fleming GR, Kirchhoff H. A proteoliposome-based system reveals how lipids control photosynthetic light harvesting. J Biol Chem 2020; 295:1857-1866. [PMID: 31929108 DOI: 10.1074/jbc.ra119.011707] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/09/2020] [Indexed: 11/06/2022] Open
Abstract
Integral membrane proteins are exposed to a complex and dynamic lipid environment modulated by nonbilayer lipids that can influence protein functions by lipid-protein interactions. The nonbilayer lipid monogalactosyldiacylglycerol (MGDG) is the most abundant lipid in plant photosynthetic thylakoid membranes, but its impact on the functionality of energy-converting membrane protein complexes is unknown. Here, we optimized a detergent-based reconstitution protocol to develop a proteoliposome technique that incorporates the major light-harvesting complex II (LHCII) into compositionally well-defined large unilamellar lipid bilayer vesicles to study the impact of MGDG on light harvesting by LHCII. Using steady-state fluorescence spectroscopy, CD spectroscopy, and time-correlated single-photon counting, we found that both chlorophyll fluorescence quantum yields and fluorescence lifetimes clearly indicate that the presence of MGDG in lipid bilayers switches LHCII from a light-harvesting to a more energy-quenching mode that dissipates harvested light into heat. It is hypothesized that in the in vitro system developed here, MGDG controls light harvesting of LHCII by modulating the hydrostatic lateral membrane pressure profile in the lipid bilayer sensed by LHCII-bound peripheral pigments.
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Affiliation(s)
- Stefanie Tietz
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Michelle Leuenberger
- Department of Chemistry, University of California, Berkeley, California 94720; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Ricarda Höhner
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Alice H Olson
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, California 94720; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, 99164-6340.
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85
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Kaur H, Grahl A, Hartmann JB, Hiller S. Sample Preparation and Technical Setup for NMR Spectroscopy with Integral Membrane Proteins. Methods Mol Biol 2020; 2127:373-396. [PMID: 32112334 DOI: 10.1007/978-1-0716-0373-4_24] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
NMR spectroscopy is a method of choice to characterize structure, function, and dynamics of integral membrane proteins at atomic resolution. Here, we describe protocols for sample preparation and characterization by NMR spectroscopy of two integral membrane proteins with different architecture, the α-helical membrane protein MsbA and the β-barrel membrane protein BamA. The protocols describe recombinant expression in E. coli, protein refolding, purification, and reconstitution in suitable membrane mimetics, as well as key setup steps for basic NMR experiments. These include experiments on protein samples in the solid state under magic angle spinning (MAS) conditions and experiments on protein samples in aqueous solution. Since MsbA and BamA are typical examples of their respective architectural classes, the protocols presented here can also serve as a reference for other integral membrane proteins.
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Affiliation(s)
- Hundeep Kaur
- Biozentrum, University of Basel, Basel, Switzerland
| | - Anne Grahl
- Biozentrum, University of Basel, Basel, Switzerland
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86
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Calmet P, Cullin C, Cortès S, Vang M, Caudy N, Baccouch R, Dessolin J, Maamar NT, Lecomte S, Tillier B, Alves ID. Cholesterol impacts chemokine CCR5 receptor ligand-binding activity. FEBS J 2019; 287:2367-2385. [PMID: 31738467 DOI: 10.1111/febs.15145] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/27/2019] [Accepted: 11/16/2019] [Indexed: 01/03/2023]
Abstract
The chemokine CCR5 receptor is target of maraviroc, a negative allosteric modulator of CCR5 that blocks the HIV protein gp120 from associating with the receptor, thereby inhibiting virus cellular entry. As noted with other G-protein-coupled receptor family members, the role of the lipid environment in CCR5 signaling remains obscure and very modestly investigated. Controversial literature on the impact of cholesterol (Chol) depletion in HIV infection and CCR5 signaling, including the hypothesis that Chol depletion could inhibit HIV infection, lead us to focus on the understanding of Chol impact in the first stages of receptor activation. To address this aim, the approach chosen was to employ reconstituted model lipid systems of controlled lipid composition containing CCR5 from two distinct expression systems: Pichia pastoris and cell-free expression. The characterization of receptor/ligand interaction in terms of total binding or competition binding assays was independently performed by plasmon waveguide resonance and fluorescence anisotropy, respectively. Maraviroc, a potent receptor antagonist, was the ligand investigated. Additionally, coarse-grained molecular dynamics simulation was employed to investigate Chol impact in the receptor-conformational flexibility and dynamics. Results obtained with receptor produced by different expression systems and using different biophysical approaches clearly demonstrate a considerable impact of Chol in the binding affinity of maraviroc to the receptor and receptor-conformational dynamics. Chol considerably decreases maraviroc binding affinity to the CCR5 receptor. The mechanisms by which this effect occurs seem to involve the adoption of distinct receptor-conformational states with restrained structural dynamics and helical motions in the presence of Chol.
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Affiliation(s)
- Pierre Calmet
- CBMN, UMR 5248 CNRS, University of Bordeaux, Pessac, France
| | | | | | - Maylou Vang
- CBMN, UMR 5248 CNRS, University of Bordeaux, Pessac, France
| | - Nada Caudy
- CBMN, UMR 5248 CNRS, University of Bordeaux, Pessac, France
| | - Rim Baccouch
- CBMN, UMR 5248 CNRS, University of Bordeaux, Pessac, France
| | - Jean Dessolin
- CBMN, UMR 5248 CNRS, University of Bordeaux, Pessac, France
| | | | - Sophie Lecomte
- CBMN, UMR 5248 CNRS, University of Bordeaux, Pessac, France
| | | | - Isabel D Alves
- CBMN, UMR 5248 CNRS, University of Bordeaux, Pessac, France
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87
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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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88
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Single Proteoliposome High-Content Analysis Reveals Differences in the Homo-Oligomerization of GPCRs. Biophys J 2019; 115:300-312. [PMID: 30021106 DOI: 10.1016/j.bpj.2018.05.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 11/23/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) control vital cellular signaling pathways. GPCR oligomerization is proposed to increase signaling diversity. However, many reports have arrived at disparate conclusions regarding the existence, stability, and stoichiometry of GPCR oligomers, partly because of cellular complexity and ensemble averaging of intrareconstitution heterogeneities that complicate the interpretation of oligomerization data. To overcome these limitations, we exploited fluorescence-microscopy-based high-content analysis of single proteoliposomes. This allowed multidimensional quantification of intrinsic monomer-monomer interactions of three class A GPCRs (β2-adrenergic receptor, cannabinoid receptor type 1, and opsin). Using a billion-fold less protein than conventional assays, we quantified oligomer stoichiometries, association constants, and the influence of two ligands and membrane curvature on oligomerization, revealing key similarities and differences for three GPCRs with decidedly different physiological functions. The assays introduced here will assist with the quantitative experimental observation of oligomerization for transmembrane proteins in general.
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89
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Mirzaei Garakani T, Liu Z, Glebe U, Gehrmann J, Lazar J, Mertens MAS, Möller M, Hamzelui N, Zhu L, Schnakenberg U, Böker A, Schwaneberg U. In Situ Monitoring of Membrane Protein Insertion into Block Copolymer Vesicle Membranes and Their Spreading via Potential-Assisted Approach. ACS APPLIED MATERIALS & INTERFACES 2019; 11:29276-29289. [PMID: 31329408 DOI: 10.1021/acsami.9b09302] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Synthosomes are polymer vesicles with transmembrane proteins incorporated into block copolymer membranes. They have been used for selective transport in or out of the vesicles as well as catalysis inside the compartments. However, both the insertion process of the membrane protein, forming nanopores, and the spreading of the vesicles on planar substrates to form solid-supported biomimetic membranes have been rarely studied yet. Herein, we address these two points and, first, shed light on the real-time monitoring of protein insertion via isothermal titration calorimetry. Second, the spreading process on different solid supports, namely, SiO2, glass, and gold, via different techniques like spin- and dip-coating as well as a completely new approach of potential-assisted spreading on gold surfaces was studied. While inhomogeneous layers occur via traditional methods, our proposed potential-assisted strategy to induce adsorption of positively charged vesicles by applying negative potential on the electrode leads to remarkable vesicle spreading and their further fusion to form more homogeneous planar copolymer films on gold. The polymer vesicles in our study are formed from amphiphilic copolymers poly(2-methyl oxazoline)-block-poly(dimethylsiloxane)-block-poly(2-methyl oxazoline) (PMOXA-b-PDMS-b-PMOXA). Engineered variants of the transmembrane protein ferric hydroxamate uptake protein component A (FhuA), one of the largest β-barrel channel proteins, are used as model nanopores. The incorporation of FhuA Δ1-160 is shown to facilitate the vesicle spreading process further. Moreover, high accessibility of cysteine inside the channel was proven by linkage of a fluorescent dye inside the engineered variant FhuA ΔCVFtev and hence preserved functionality of the channels after spreading. The porosity and functionality of the spread synthosomes on the gold plates have been examined by studying the passive ion transport response in the presence of Li+ and ClO4- ions and electrochemical impedance spectroscopy analysis. Our approach to form solid-supported biomimetic membranes via the potential-assisted strategy could be important for the development of new (bio-) sensors and membranes.
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Affiliation(s)
- Tayebeh Mirzaei Garakani
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
- DWI - Leibniz Institute for Interactive Materials , Forckenbeckstraße 50 , D-52074 , Aachen , Germany
| | - Zhanzhi Liu
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Ulrich Glebe
- Fraunhofer Institute for Applied Polymer Research IAP , Geiselbergstraße 69 , 14476 Potsdam -Golm, Germany
- Chair of Polymer Materials and Polymer Technologies, Institute of Chemistry , University of Potsdam , Karl-Liebknecht-Str. 24-25 , 14476 Potsdam -Golm, Germany
| | - Julia Gehrmann
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Jaroslav Lazar
- Institute of Materials in Electrical Engineering 1 , RWTH Aachen University , Sommerfeldstraße 24 , 52074 Aachen , Germany
| | | | - Mieke Möller
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Niloofar Hamzelui
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Leilei Zhu
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
| | - Uwe Schnakenberg
- Institute of Materials in Electrical Engineering 1 , RWTH Aachen University , Sommerfeldstraße 24 , 52074 Aachen , Germany
| | - Alexander Böker
- Fraunhofer Institute for Applied Polymer Research IAP , Geiselbergstraße 69 , 14476 Potsdam -Golm, Germany
- Chair of Polymer Materials and Polymer Technologies, Institute of Chemistry , University of Potsdam , Karl-Liebknecht-Str. 24-25 , 14476 Potsdam -Golm, Germany
| | - Ulrich Schwaneberg
- Institute of Biotechnology , RWTH Aachen University , Worringer Weg 3 , D-52074 Aachen , Germany
- DWI - Leibniz Institute for Interactive Materials , Forckenbeckstraße 50 , D-52074 , Aachen , Germany
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90
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Chen W, Guo J, Cai Y, Fu Q, Chen B, Chou JJ. Unidirectional Presentation of Membrane Proteins in Nanoparticle-Supported Liposomes. Angew Chem Int Ed Engl 2019; 58:9866-9870. [PMID: 30990942 PMCID: PMC6660371 DOI: 10.1002/anie.201903093] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Indexed: 12/30/2022]
Abstract
Presentation of membrane proteins to host immune systems has been a challenging problem owing to complexity arising from the poor in vivo stability of the membrane-mimetic media often used for solubilizing the membrane proteins. The use of functionalized, biocompatible nanoparticles as substrates is shown to guide the formation of proteoliposomes, which can present many copies of membrane proteins in a unidirectional manner. The approach was demonstrated to present the membrane-proximal region of the HIV-1 envelope glycoprotein. These nanoparticle-supported liposomes are broadly applicable as membrane antigen vehicles for inducing host immune responses.
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Affiliation(s)
- Wen Chen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, United States
| | - Junling Guo
- Department of Biomass Science and Engineering, Sichuan University, 252 Shuncheng Street, Chengdu, Sichuan 610065, China
| | - Yongfei Cai
- Division of Molecular Medicine, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, 3 Blackfan Street, Boston, MA 02115, United States
| | - Qingshan Fu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, United States
| | - Bing Chen
- Division of Molecular Medicine, Boston Children’s Hospital, Department of Pediatrics, Harvard Medical School, 3 Blackfan Street, Boston, MA 02115, United States
| | - James J. Chou
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, United States
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91
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Chen W, Cai Y, Fu Q, Chen B, Guo J, Chou JJ. Unidirectional Presentation of Membrane Proteins in Nanoparticle‐Supported Liposomes. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201903093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Wen Chen
- Department of Biological Chemistry and Molecular PharmacologyHarvard Medical School 250 Longwood Avenue Boston MA 02115 USA
| | - Yongfei Cai
- Division of Molecular MedicineBoston Children's HospitalDepartment of PediatricsHarvard Medical School 3 Blackfan Street Boston MA 02115 USA
| | - Qingshan Fu
- Department of Biological Chemistry and Molecular PharmacologyHarvard Medical School 250 Longwood Avenue Boston MA 02115 USA
| | - Bing Chen
- Division of Molecular MedicineBoston Children's HospitalDepartment of PediatricsHarvard Medical School 3 Blackfan Street Boston MA 02115 USA
| | - Junling Guo
- Department of Biomass Science and EngineeringSichuan University 24 South Section Yihuan Road Chengdu Sichuan 610065 China
| | - James J. Chou
- Department of Biological Chemistry and Molecular PharmacologyHarvard Medical School 250 Longwood Avenue Boston MA 02115 USA
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92
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Qiu C, Han HH, Sun J, Zhang HT, Wei W, Cui SH, Chen X, Wang JC, Zhang Q. Regulating intracellular fate of siRNA by endoplasmic reticulum membrane-decorated hybrid nanoplexes. Nat Commun 2019; 10:2702. [PMID: 31221991 PMCID: PMC6586638 DOI: 10.1038/s41467-019-10562-w] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 05/17/2019] [Indexed: 01/07/2023] Open
Abstract
Most cationic vectors are difficult to avoid the fate of small interfering RNA (siRNA) degradation following the endosome-lysosome pathway during siRNA transfection. In this study, the endoplasmic reticulum (ER) membrane isolated from cancer cells was used to fabricate an integrative hybrid nanoplexes (EhCv/siRNA NPs) for improving siRNA transfection. Compared to the undecorated Cv/siEGFR NPs, the ER membrane-decorated EhCv/siRNA NPs exhibits a significantly higher gene silencing effect of siRNA in vitro and a better antitumor activity in nude mice bearing MCF-7 human breast tumor in vivo. Further mechanistic studies demonstrate that functional proteins on the ER membrane plays important roles on improving cellular uptake and altering intracellular trafficking pathway of siRNA. It is worth to believe that the ER membrane decoration on nanoplexes can effectively transport siRNA through the endosome-Golgi-ER pathway to evade lysosomal degradation and enhance the silencing effects of siRNA.
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Affiliation(s)
- Chong Qiu
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China
| | - Hu-Hu Han
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China
| | - Jing Sun
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China
| | - Hai-Tao Zhang
- Xiangya School of Pharmaceutical Sciences, Central South University, 410013, Changsha, China
| | - Wei Wei
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China
| | - Shi-He Cui
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China
| | - Xin Chen
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China
| | - Jian-Cheng Wang
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China.
| | - Qiang Zhang
- Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 100191, Beijing, China
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93
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Ge Y, Gao J, Jordan R, Naumann CA. Changes in Cholesterol Level Alter Integrin Sequestration in Raft-Mimicking Lipid Mixtures. Biophys J 2019; 114:158-167. [PMID: 29320683 DOI: 10.1016/j.bpj.2017.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 11/06/2017] [Indexed: 11/30/2022] Open
Abstract
The influence of cholesterol (CHOL) level on integrin sequestration in raft-mimicking lipid mixtures forming coexisting liquid-ordered (lo) and liquid-disordered (ld) lipid domains is investigated using complementary, single-molecule-sensitive, confocal detection methods. Systematic analysis of membrane protein distribution in such a model membrane environment demonstrates that variation of CHOL level has a profound influence on lo-ld sequestration of integrins, thereby exhibiting overall ld preference in the absence of ligands and lo affinity upon vitronectin addition. Accompanying photon-counting histogram analysis of integrins in the different model membrane mixtures shows that the observed changes of integrin sequestration in response to variations of membrane CHOL level are not associated with altering integrin oligomerization states. Instead, our experiments suggest that the strong CHOL dependence of integrin sequestration can be attributed to CHOL-mediated changes of lipid packing and bilayer thickness in coexisting lo and ld domains, highlighting the significance of a biophysical mechanism of CHOL-mediated regulation of integrin sequestration. We envision that this model membrane study may help clarify the influence of CHOL in integrin functionality in plasma membranes, thus providing further insight into the role of lipid heterogeneities in membrane protein distribution and function in a cellular membrane environment.
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Affiliation(s)
- Yifan Ge
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana
| | - Jiayun Gao
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana
| | - Rainer Jordan
- Makromolekulare Chemie, TU Dresden, Dresden, Germany
| | - Christoph A Naumann
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana; Integrated Nanosystems Development Institute, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana.
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94
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Akhtar P, Görföl F, Garab G, Lambrev PH. Dependence of chlorophyll fluorescence quenching on the lipid-to-protein ratio in reconstituted light-harvesting complex II membranes containing lipid labels. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2019.03.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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95
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Royes J, Ilioaia O, Lubart Q, Angius F, Dubacheva GV, Bally M, Miroux B, Tribet C. Bacteria‐Based Production of Thiol‐Clickable, Genetically Encoded Lipid Nanovesicles. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jorge Royes
- PASTEURDépartement de ChimieÉcole Normale SuperiéurePSL UniversitySorbonne UniversitéCNRS 24 rue Lhomond 75005 Paris France
- UMR7099Institut de Biologie Physico-ChimiqueCNRSUniv. Paris DiderotSorbonne Université 13 rue Pierre et Marie Curie 75005 Paris France
| | - Oana Ilioaia
- UMR7099Institut de Biologie Physico-ChimiqueCNRSUniv. Paris DiderotSorbonne Université 13 rue Pierre et Marie Curie 75005 Paris France
| | - Quentin Lubart
- Department of PhysicsChalmers University of Technology Gothenburg Sweden
| | - Federica Angius
- UMR7099Institut de Biologie Physico-ChimiqueCNRSUniv. Paris DiderotSorbonne Université 13 rue Pierre et Marie Curie 75005 Paris France
- Present Address: Department of MicrobiologyInstitute for Water and Wetland Research Heyendaalseweg 135 6525 Nijmegen The Netherlands
| | - Galina V. Dubacheva
- PPSMCNRSÉcole Normale Supérieure Paris-SaclayUniversité Paris-Saclay 61 Avenue du Président Wilson 94235 Cachan France
| | - Marta Bally
- Department of PhysicsChalmers University of Technology Gothenburg Sweden
| | - Bruno Miroux
- UMR7099Institut de Biologie Physico-ChimiqueCNRSUniv. Paris DiderotSorbonne Université 13 rue Pierre et Marie Curie 75005 Paris France
| | - Christophe Tribet
- PASTEURDépartement de ChimieÉcole Normale SuperiéurePSL UniversitySorbonne UniversitéCNRS 24 rue Lhomond 75005 Paris France
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96
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An SQ, Murtagh J, Twomey KB, Gupta MK, O'Sullivan TP, Ingram R, Valvano MA, Tang JL. Modulation of antibiotic sensitivity and biofilm formation in Pseudomonas aeruginosa by interspecies signal analogues. Nat Commun 2019; 10:2334. [PMID: 31133642 PMCID: PMC6536496 DOI: 10.1038/s41467-019-10271-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 04/24/2019] [Indexed: 11/15/2022] Open
Abstract
Pseudomonas aeruginosa, a significant opportunistic pathogen, can participate in inter-species communication through signaling by cis-2-unsaturated fatty acids of the diffusible signal factor (DSF) family. Sensing these signals leads to altered biofilm formation and increased tolerance to various antibiotics, and requires the histidine kinase PA1396. Here, we show that the membrane-associated sensory input domain of PA1396 has five transmembrane helices, two of which are required for DSF sensing. DSF binding is associated with enhanced auto-phosphorylation of PA1396 incorporated into liposomes. Further, we examined the ability of synthetic DSF analogues to modulate or inhibit PA1396 activity. Several of these analogues block the ability of DSF to trigger auto-phosphorylation and gene expression, whereas others act as inverse agonists reducing biofilm formation and antibiotic tolerance, both in vitro and in murine infection models. These analogues may thus represent lead compounds to develop novel adjuvants improving the efficacy of existing antibiotics.
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Affiliation(s)
- Shi-Qi An
- National Biofilms Innovation Centers, Biological Sciences, University of Southampton, Southampton, SO17 1BJ, UK.
- The Wellcome-Wolfson Institute for Experimental Medicine, Queen's University of Belfast, Belfast, BT9 7BL, UK.
| | - Julie Murtagh
- School of Microbiology, Biosciences Institute, University College Cork, Cork, T12, Ireland
| | - Kate B Twomey
- School of Microbiology, Biosciences Institute, University College Cork, Cork, T12, Ireland
| | - Manoj K Gupta
- School of Chemistry, University College Cork, Cork, T12, Ireland
- Department of Chemistry, Central University of Haryana, Mahendergarh, 123029, Haryana, India
| | - Timothy P O'Sullivan
- School of Chemistry, University College Cork, Cork, T12, Ireland
- School of Pharmacy, University College Cork, Cork, T12, Ireland
| | - Rebecca Ingram
- The Wellcome-Wolfson Institute for Experimental Medicine, Queen's University of Belfast, Belfast, BT9 7BL, UK
| | - Miguel A Valvano
- The Wellcome-Wolfson Institute for Experimental Medicine, Queen's University of Belfast, Belfast, BT9 7BL, UK.
| | - Ji-Liang Tang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning, 530004, China.
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97
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Kühnel RM, Grifell-Junyent M, Jørgensen IL, Kemmer GC, Schiller J, Palmgren M, Justesen BH, Günther Pomorski T. Short-chain lipid-conjugated pH sensors for imaging of transporter activities in reconstituted systems and living cells. Analyst 2019; 144:3030-3037. [PMID: 30901016 DOI: 10.1039/c8an02161a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The design of ion sensors has gained importance for the study of ion dynamics in cells, with fluorescent proton nanosensors attracting particular interest because of their applicability in monitoring pH gradients in biological microcompartments and reconstituted membrane systems. In this work, we describe the improved synthesis, photophysical properties and applications of pH sensors based on amine-reactive pHrodo esters and short-chain lipid derivatives of phosphoethanolamine. The major features of these novel probes include strong fluorescence under acidic conditions, efficient partitioning into membranes, and extractability by back exchange to albumin. These features allow for the selective labeling of the inner liposomal leaflet in reconstituted membrane systems for studying proton pumping activities in a quantitative fashion, as demonstrated by assaying the activity of a plant plasma membrane H+-ATPase. Furthermore, the short-chain lipid-conjugated pH sensors enable the monitoring of pH changes from neutral to acidic conditions in the endocytic pathway of living cells. Collectively, our results demonstrate the applicability of short-chain lipid-conjugated sensors for in vivo and in vitro studies and thus pave the way for the design of lipid-conjugated sensors selective to other biologically relevant ions, e.g. calcium and sodium.
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Affiliation(s)
- Ronja Marie Kühnel
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Universitätstrasse 150, D-44780 Bochum, Germany.
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98
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Royes J, Ilioaia O, Lubart Q, Angius F, Dubacheva GV, Bally M, Miroux B, Tribet C. Bacteria-Based Production of Thiol-Clickable, Genetically Encoded Lipid Nanovesicles. Angew Chem Int Ed Engl 2019; 58:7395-7399. [PMID: 30934157 DOI: 10.1002/anie.201902929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Indexed: 12/31/2022]
Abstract
Despite growing research efforts on the preparation of (bio)functional liposomes, synthetic capsules cannot reach the densities of protein loading and the control over peptide display that is achieved by natural vesicles. Herein, a microbial platform for high-yield production of lipidic nanovesicles with clickable thiol moieties in their outer corona is reported. These nanovesicles show low size dispersity, are decorated with a dense, perfectly oriented, and customizable corona of transmembrane polypeptides. Furthermore, this approach enables encapsulation of soluble proteins into the nanovesicles. Due to the mild preparation and loading conditions (absence of organic solvents, pH gradients, or detergents) and their straightforward surface functionalization, which takes advantage of the diversity of commercially available maleimide derivatives, bacteria-based proteoliposomes are an attractive eco-friendly alternative that can outperform currently used liposomes.
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Affiliation(s)
- Jorge Royes
- PASTEUR, Département de Chimie, École Normale Superiéure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, 75005, Paris, France.,UMR7099, Institut de Biologie Physico-Chimique, CNRS, Univ. Paris Diderot, Sorbonne Université, 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Oana Ilioaia
- UMR7099, Institut de Biologie Physico-Chimique, CNRS, Univ. Paris Diderot, Sorbonne Université, 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Quentin Lubart
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Federica Angius
- UMR7099, Institut de Biologie Physico-Chimique, CNRS, Univ. Paris Diderot, Sorbonne Université, 13 rue Pierre et Marie Curie, 75005, Paris, France.,Present Address: Department of Microbiology, Institute for Water and Wetland Research, Heyendaalseweg 135, 6525, Nijmegen, The Netherlands
| | - Galina V Dubacheva
- PPSM, CNRS, École Normale Supérieure Paris-Saclay, Université Paris-Saclay, 61 Avenue du Président Wilson, 94235, Cachan, France
| | - Marta Bally
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Bruno Miroux
- UMR7099, Institut de Biologie Physico-Chimique, CNRS, Univ. Paris Diderot, Sorbonne Université, 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Christophe Tribet
- PASTEUR, Département de Chimie, École Normale Superiéure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, 75005, Paris, France
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99
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Omidvar R, Römer W. Glycan-decorated protocells: novel features for rebuilding cellular processes. Interface Focus 2019; 9:20180084. [PMID: 30842879 PMCID: PMC6388021 DOI: 10.1098/rsfs.2018.0084] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2019] [Indexed: 02/06/2023] Open
Abstract
In synthetic biology approaches, lipid vesicles are widely used as protocell models. While many compounds have been encapsulated in vesicles (e.g. DNA, cytoskeleton and enzymes), the incorporation of glycocalyx components in the lipid bilayer has attracted much less attention so far. In recent years, glycoconjugates have been integrated in the membrane of giant unilamellar vesicles (GUVs). These minimal membrane systems have largely contributed to shed light on the molecular mechanisms of cellular processes. In this review, we first introduce several preparation and biophysical characterization methods of GUVs. Then, we highlight specific applications of protocells investigating glycolipid-mediated endocytosis of toxins, viruses and bacteria. In addition, we delineate how prototissues have been assembled from glycan-decorated protocells by using lectin-mediated cross-linking of opposed glycoreceptors (e.g. glycolipids and glycopeptides). In future applications, glycan-decorated protocells might be useful for investigating cell-cell interactions (e.g. adhesion and communication). We also speculate about the implication of lectin-glycoreceptor interactions in membrane fusion processes.
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Affiliation(s)
- Ramin Omidvar
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
| | - Winfried Römer
- Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestraße 1, 79104 Freiburg, Germany
- Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, Schänzlestraße 18, 79104 Freiburg, Germany
- Freiburg Center for Interactive Materials and Bioinspired Technology (FIT), Albert-Ludwigs-University Freiburg, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
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100
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Iatmanen-Harbi S, Senicourt L, Papadopoulos V, Lequin O, Lacapere JJ. Characterization of the High-Affinity Drug Ligand Binding Site of Mouse Recombinant TSPO. Int J Mol Sci 2019; 20:ijms20061444. [PMID: 30901938 PMCID: PMC6470738 DOI: 10.3390/ijms20061444] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 02/08/2023] Open
Abstract
The optimization of translocator protein (TSPO) ligands for Positron Emission Tomography as well as for the modulation of neurosteroids is a critical necessity for the development of TSPO-based diagnostics and therapeutics of neuropsychiatrics and neurodegenerative disorders. Structural hints on the interaction site and ligand binding mechanism are essential for the development of efficient TSPO ligands. Recently published atomic structures of recombinant mammalian and bacterial TSPO1, bound with either the high-affinity drug ligand PK 11195 or protoporphyrin IX, have revealed the membrane protein topology and the ligand binding pocket. The ligand is surrounded by amino acids from the five transmembrane helices as well as the cytosolic loops. However, the precise mechanism of ligand binding remains unknown. Previous biochemical studies had suggested that ligand selectivity and binding was governed by these loops. We performed site-directed mutagenesis to further test this hypothesis and measured the binding affinities. We show that aromatic residues (Y34 and F100) from the cytosolic loops contribute to PK 11195 access to its binding site. Limited proteolytic digestion, circular dichroism and solution two-dimensional (2-D) NMR using selective amino acid labelling provide information on the intramolecular flexibility and conformational changes in the TSPO structure upon PK 11195 binding. We also discuss the differences in the PK 11195 binding affinities and the primary structure between TSPO (TSPO1) and its paralogous gene product TSPO2.
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Affiliation(s)
- Soria Iatmanen-Harbi
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
| | - Lucile Senicourt
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
| | - Vassilios Papadopoulos
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90089, USA.
| | - Olivier Lequin
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
| | - Jean-Jacques Lacapere
- Sorbonne Université, Ecole Normale Supérieure, PSL University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, F-75005 Paris, France.
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