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Martinez D, Decossas M, Kowal J, Frey L, Stahlberg H, Dufourc EJ, Riek R, Habenstein B, Bibow S, Loquet A. Lipid Internal Dynamics Probed in Nanodiscs. Chemphyschem 2017; 18:2651-2657. [PMID: 28573816 PMCID: PMC5697661 DOI: 10.1002/cphc.201700450] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Indexed: 11/29/2022]
Abstract
Nanodiscs offer a very promising tool to incorporate membrane proteins into native-like lipid bilayers and an alternative to liposomes to maintain protein functions and protein-lipid interactions in a soluble nanoscale object. The activity of the incorporated membrane protein appears to be correlated to its dynamics in the lipid bilayer and by protein-lipid interactions. These two parameters depend on the lipid internal dynamics surrounded by the lipid-encircling discoidal scaffold protein that might differ from more unrestricted lipid bilayers observed in vesicles or cellular extracts. A solid-state NMR spectroscopy investigation of lipid internal dynamics and thermotropism in nanodiscs is reported. The gel-to-fluid phase transition is almost abolished for nanodiscs, which maintain lipid fluid properties for a large temperature range. The addition of cholesterol allows fine-tuning of the internal bilayer dynamics by increasing chain ordering. Increased site-specific order parameters along the acyl chain reflect a higher internal ordering in nanodiscs compared with liposomes at room temperature; this is induced by the scaffold protein, which restricts lipid diffusion in the nanodisc area.
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Affiliation(s)
- Denis Martinez
- CBMNCNRS.University of BordeauxIECBAll. Geoffroy Saint-Hilaire34600PessacFrance
| | - Marion Decossas
- CBMNCNRS.University of BordeauxIECBAll. Geoffroy Saint-Hilaire34600PessacFrance
| | - Julia Kowal
- D C-CINAUniversity of Basel4058BaselSwitzerland
| | - Lukas Frey
- Laboratory for Physical ChemistryETH Zürich8093ZürichSwitzerland
| | | | - Erick J. Dufourc
- CBMNCNRS.University of BordeauxIECBAll. Geoffroy Saint-Hilaire34600PessacFrance
| | - Roland Riek
- Laboratory for Physical ChemistryETH Zürich8093ZürichSwitzerland
| | - Birgit Habenstein
- CBMNCNRS.University of BordeauxIECBAll. Geoffroy Saint-Hilaire34600PessacFrance
| | - Stefan Bibow
- BiozentrumUniversity of Basel4058BaselSwitzerland
| | - Antoine Loquet
- CBMNCNRS.University of BordeauxIECBAll. Geoffroy Saint-Hilaire34600PessacFrance
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52
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Zoghbi ME, Altenberg GA. Luminescence resonance energy transfer spectroscopy of ATP-binding cassette proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:854-867. [PMID: 28801111 DOI: 10.1016/j.bbamem.2017.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 12/11/2022]
Abstract
The ATP-binding cassette (ABC) superfamily includes regulatory and transport proteins. Most human ABC exporters pump substrates out of cells using energy from ATP hydrolysis. Although major advances have been made toward understanding the molecular mechanism of ABC exporters, there are still many issues unresolved. During the last few years, luminescence resonance energy transfer has been used to detect conformational changes in real time, with atomic resolution, in isolated ABC nucleotide binding domains (NBDs) and full-length ABC exporters. NBDs are particularly interesting because they provide the power stroke for substrate transport. Luminescence resonance energy transfer (LRET) is a spectroscopic technique that can provide dynamic information with atomic-resolution of protein conformational changes under physiological conditions. Using LRET, it has been shown that NBD dimerization, a critical step in ABC proteins catalytic cycle, requires binding of ATP to two nucleotide binding sites. However, hydrolysis at just one of the sites can drive dissociation of the NBD dimer. It was also found that the NBDs of the bacterial ABC exporter MsbA reconstituted in a lipid bilayer membrane and studied at 37°C never separate as much as suggested by crystal structures. This observation stresses the importance of performing structural/functional studies of ABC exporters under physiologic conditions. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.
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Affiliation(s)
- Maria E Zoghbi
- School of Natural Sciences, University of California, Merced, 4225 N. Hospital Road, Atwater, CA, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79423-6551, USA.
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53
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Heberle FA, Pabst G. Complex biomembrane mimetics on the sub-nanometer scale. Biophys Rev 2017; 9:353-373. [PMID: 28717925 PMCID: PMC5578918 DOI: 10.1007/s12551-017-0275-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 06/26/2017] [Indexed: 12/12/2022] Open
Abstract
Biomimetic lipid vesicles are indispensable tools for gaining insight into the biophysics of cell physiology on the molecular level. The level of complexity of these model systems has steadily increased, and now spans from domain-forming lipid mixtures to asymmetric lipid bilayers. Here, we review recent progress in the development and application of elastic neutron and X-ray scattering techniques for studying these systems in situ and under physiologically relevant conditions on the nanometer to sub-nanometer length scales. In particular, we focus on: (1) structural details of coexisting liquid-ordered and liquid-disordered domains, including their thickness and lipid packing mismatch as a function of a size transition from nanoscopic to macroscopic domains; (2) membrane-mediated protein partitioning into lipid domains; (3) the role of the aqueous medium in tuning interactions between membranes and domains; and (4) leaflet-specific structure in asymmetric bilayers and passive lipid flip-flop.
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Affiliation(s)
- Frederick A Heberle
- The Bredesen Center, University of Tennessee, Knoxville, TN, 37996, USA.,Joint Institute for Biological Sciences and Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Georg Pabst
- Institute of Molecular Biosciences, Biophysics Division, NAWI Graz, University of Graz, 8010, Graz, Austria. .,BioTechMed-Graz, 8010, Graz, Austria.
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54
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Rouck J, Krapf J, Roy J, Huff H, Das A. Recent advances in nanodisc technology for membrane protein studies (2012-2017). FEBS Lett 2017; 591:2057-2088. [PMID: 28581067 PMCID: PMC5751705 DOI: 10.1002/1873-3468.12706] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/26/2017] [Accepted: 05/31/2017] [Indexed: 01/01/2023]
Abstract
Historically, the main barrier to membrane protein investigations has been the tendency of membrane proteins to aggregate (due to their hydrophobic nature), in aqueous solution as well as on surfaces. The introduction of biomembrane mimetics has since stimulated momentum in the field. One such mimetic, the nanodisc (ND) system, has proved to be an exceptional system for solubilizing membrane proteins. Herein, we critically evaluate the advantages and imperfections of employing nanodiscs in biophysical and biochemical studies. Specifically, we examine the techniques that have been modified to study membrane proteins in nanodiscs. Techniques discussed here include fluorescence microscopy, solution-state/solid-state nuclear magnetic resonance, electron microscopy, small-angle X-ray scattering, and several mass spectroscopy methods. Newer techniques such as SPR, charge-sensitive optical detection, and scintillation proximity assays are also reviewed. Lastly, we cover how nanodiscs are advancing nanotechnology through nanoplasmonic biosensing, lipoprotein-nanoplatelets, and sortase-mediated labeling of nanodiscs.
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Affiliation(s)
- John Rouck
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - John Krapf
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - Jahnabi Roy
- Department of Chemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - Hannah Huff
- Department of Chemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - Aditi Das
- Department of Comparative Biosciences, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
- Beckman Institute for Advanced Science, Division of Nutritional Sciences, Neuroscience Program and Department of Bioengineering, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
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55
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Hansen S. DLSanalysis.org: a web interface for analysis of dynamic light scattering data. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2017. [DOI: 10.1007/s00249-017-1232-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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56
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Abstract
Membrane proteins play a most important part in metabolism, signaling, cell motility, transport, development, and many other biochemical and biophysical processes which constitute fundamentals of life on the molecular level. Detailed understanding of these processes is necessary for the progress of life sciences and biomedical applications. Nanodiscs provide a new and powerful tool for a broad spectrum of biochemical and biophysical studies of membrane proteins and are commonly acknowledged as an optimal membrane mimetic system that provides control over size, composition, and specific functional modifications on the nanometer scale. In this review we attempted to combine a comprehensive list of various applications of nanodisc technology with systematic analysis of the most attractive features of this system and advantages provided by nanodiscs for structural and mechanistic studies of membrane proteins.
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Affiliation(s)
- Ilia G Denisov
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
| | - Stephen G Sligar
- Department of Biochemistry and Department of Chemistry, University of Illinois , Urbana, Illinois 61801, United States
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57
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Gabel F. Applications of SANS to Study Membrane Protein Systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1009:201-214. [DOI: 10.1007/978-981-10-6038-0_12] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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58
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The power, pitfalls and potential of the nanodisc system for NMR-based studies. Biol Chem 2016; 397:1335-1354. [DOI: 10.1515/hsz-2016-0224] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/19/2016] [Indexed: 12/21/2022]
Abstract
Abstract
The choice of a suitable membrane mimicking environment is of fundamental importance for the characterization of structure and function of membrane proteins. In this respect, usage of the lipid bilayer nanodisc technology provides a unique potential for nuclear magnetic resonance (NMR)-based studies. This review summarizes the recent advances in this field, focusing on (i) the strengths of the system, (ii) the bottlenecks that may be faced, and (iii) promising capabilities that may be explored in future studies.
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59
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Simonsen JB. Evaluation of reconstituted high-density lipoprotein (rHDL) as a drug delivery platform – a detailed survey of rHDL particles ranging from biophysical properties to clinical implications. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2016; 12:2161-2179. [DOI: 10.1016/j.nano.2016.05.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 05/02/2016] [Accepted: 05/05/2016] [Indexed: 12/15/2022]
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60
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Gilmore SF, Blanchette CD, Scharadin TM, Hura GL, Rasley A, Corzett M, Pan CX, Fischer NO, Henderson PT. Lipid Cross-Linking of Nanolipoprotein Particles Substantially Enhances Serum Stability and Cellular Uptake. ACS APPLIED MATERIALS & INTERFACES 2016; 8:20549-20557. [PMID: 27411034 DOI: 10.1021/acsami.6b04609] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nanolipoprotein particles (NLPs) consist of a discoidal phospholipid lipid bilayer confined by an apolipoprotein belt. NLPs are a promising platform for a variety of biomedical applications due to their biocompatibility, size, definable composition, and amphipathic characteristics. However, poor serum stability hampers the use of NLPs for in vivo applications such as drug formulation. In this study, NLP stability was enhanced upon the incorporation and subsequent UV-mediated intermolecular cross-linking of photoactive DiynePC phospholipids in the lipid bilayer, forming cross-linked nanoparticles (X-NLPs). Both the concentration of DiynePC in the bilayer and UV exposure time significantly affected the resulting X-NLP stability in 100% serum, as assessed by size exclusion chromatography (SEC) of fluorescently labeled particles. Cross-linking did not significantly impact the size of X-NLPs as determined by dynamic light scattering and SEC. X-NLPs had essentially no degradation over 48 h in 100% serum, which is a drastic improvement compared to non-cross-linked NLPs (50% degradation by ∼10 min). X-NLPs had greater uptake into the human ATCC 5637 bladder cancer cell line compared to non-cross-linked particles, indicating their potential utility for targeted drug delivery. X-NLPs also exhibited enhanced stability following intravenous administration in mice. These results collectively support the potential utility of X-NLPs for a variety of in vivo applications.
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Affiliation(s)
- Sean F Gilmore
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory , Livermore, California 94551, United States
| | - Craig D Blanchette
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory , Livermore, California 94551, United States
| | - Tiffany M Scharadin
- Department of Internal Medicine, Division of Hematology and Oncology, University of California-Davis (UC Davis) and UC Davis Comprehensive Cancer Center , 4501 X Street, Room 3016, Sacramento, California 95817, United States
| | - Greg L Hura
- Life Science Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States
- Chemistry and Biochemistry, University of California-Santa Cruz , Santa Cruz, California 95064, United States
| | - Amy Rasley
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory , Livermore, California 94551, United States
| | - Michele Corzett
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory , Livermore, California 94551, United States
| | - Chong-Xian Pan
- Department of Internal Medicine, Division of Hematology and Oncology, University of California-Davis (UC Davis) and UC Davis Comprehensive Cancer Center , 4501 X Street, Room 3016, Sacramento, California 95817, United States
| | - Nicholas O Fischer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory , Livermore, California 94551, United States
| | - Paul T Henderson
- Department of Internal Medicine, Division of Hematology and Oncology, University of California-Davis (UC Davis) and UC Davis Comprehensive Cancer Center , 4501 X Street, Room 3016, Sacramento, California 95817, United States
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61
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Larsen AN, Sørensen KK, Johansen NT, Martel A, Kirkensgaard JJK, Jensen KJ, Arleth L, Midtgaard SR. Dimeric peptides with three different linkers self-assemble with phospholipids to form peptide nanodiscs that stabilize membrane proteins. SOFT MATTER 2016; 12:5937-5949. [PMID: 27306692 DOI: 10.1039/c6sm00495d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Three dimers of the amphipathic α-helical peptide 18A have been synthesized with different interhelical linkers inserted between the two copies of 18A. The dimeric peptides were denoted 'beltides' where Beltide-1 refers to the 18A-dimer without a linker, Beltide-2 is the 18A-dimer with proline (Pro) as a linker and Beltide-3 is the 18A-dimer linked by two glycines (Gly-Gly). The self-assembly of the beltides with the phospholipid DMPC was studied with and without the incorporated membrane protein bacteriorhodopsin (bR) through a combination of coarse-grained MD simulations, size-exclusion chromatography (SEC), circular dichroism (CD) spectroscopy, small-angle scattering (SAS), static light scattering (SLS) and UV-Vis spectroscopy. For all three beltides, MD and combined small-angle X-ray and -neutron scattering were consistent with a disc structure composed by a phospholipid bilayer surrounded by a belt of peptides and with a total disc diameter of approximately 10 nm. CD confirmed that all three beltides were α-helical in the free form and with DMPC. However, as shown by SEC the different interhelical linkers clearly led to different properties of the beltides. Beltide-3, with the Gly-Gly linker, was very adaptable such that peptide nanodiscs could be formed for a broad range of different peptide to lipid stoichiometries and therefore also possible disc-sizes. On the other hand, both Beltide-2 with the Pro linker and Beltide-1 without a linker were less adaptable and would only form discs of certain peptide to lipid stoichiometries. SLS revealed that the structural stability of the formed peptide nanodiscs was also highly affected by the linkers and it was found that Beltide-1 gave more stable discs than the other two beltides. With respect to membrane protein stabilization, each of the three beltides in combination with DMPC stabilizes the seven-helix transmembrane protein bacteriorhodopsin significantly better than the detergent octyl glucoside, but no significant difference was observed between the three beltides. We conclude that adaptability, size, and structural stability can be tuned by changing the interhelical linker while maintaining the properties of the discs with respect to membrane protein stabilization.
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Affiliation(s)
| | | | | | | | | | - Knud J Jensen
- Department of Chemistry, University of Copenhagen, Denmark
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Denmark.
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62
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Midtgaard SR, Pedersen MC, Arleth L. Small-angle X-ray scattering of the cholesterol incorporation into human ApoA1-POPC discoidal particles. Biophys J 2016. [PMID: 26200866 DOI: 10.1016/j.bpj.2015.06.032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Structural and functional aspects of high-density lipoproteins have been studied for over half a century. Due to the plasticity of this highly complex system, new aspects continue to be discovered. Here, we present a structural study of the human Apolipoprotein A1 (ApoA1) and investigate the role of its N-terminal domain, the so-called globular domain of ApoA1, in discoidal complexes with phospholipids and increasing amounts of cholesterol. Using a combination of solution-based small-angle x-ray scattering (SAXS) and molecular constrained data modeling, we show that the ApoA1-1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)-based particles are disk shaped with an elliptical cross section and composed by a central lipid bilayer surrounded by two stabilizing ApoA1 proteins. This structure is very similar to the particles formed in the so-called nanodisc system, which is based on N-terminal truncated ApoA1 protein. Although it is commonly agreed that the nanodisc is plain disk shaped, several more advanced structures have been proposed for the full-length ApoA1 in combination with POPC and cholesterol. This prompted us to make a detailed comparative study of the ApoA1 and nanodisc systems upon cholesterol uptake. Based on the presented SAXS analysis it is found that the N-terminal domains of ApoA1-POPC-cholesterol particles are not globular but instead an integrated part of the protein belt stabilizing the particles. Upon incorporation of increasing amounts of cholesterol, the presence of the N-terminal domain allows the bilayer thickness to increase while maintaining an overall flat bilayer structure. This is contrasted by the energetically more strained and less favorable lens shape required to fit the SAXS data from the N-terminal truncated nanodisc system upon cholesterol incorporation. This suggests that the N-terminal domain of ApoA1 actively participates in the stabilization of the ApoA1-POPC-cholesterol discoidal particle and allows for a more optimal lipid packing upon cholesterol uptake.
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Affiliation(s)
- Søren Roi Midtgaard
- X-Ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Denmark.
| | | | - Lise Arleth
- X-Ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Denmark
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63
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Abstract
X-ray scattering is a structural characterization tool that has impacted diverse fields of study. It is unique in its ability to examine materials in real time and under realistic sample environments, enabling researchers to understand morphology at nanometer and angstrom length scales using complementary small and wide angle X-ray scattering (SAXS, WAXS), respectively. Herein, we focus on the use of SAXS to examine nanoscale particulate systems. We provide a theoretical foundation for X-ray scattering, considering both form factor and structure factor, as well as the use of correlation functions, which may be used to determine a particle's size, size distribution, shape, and organization into hierarchical structures. The theory is expanded upon with contemporary use cases. Both transmission and reflection (grazing incidence) geometries are addressed, as well as the combination of SAXS with other X-ray and non-X-ray characterization tools. We conclude with an examination of several key areas of research where X-ray scattering has played a pivotal role, including in situ nanoparticle synthesis, nanoparticle assembly, and operando studies of catalysts and energy storage materials. Throughout this review we highlight the unique capabilities of X-ray scattering for structural characterization of materials in their native environment.
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Affiliation(s)
- Tao Li
- X-ray Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Andrew J Senesi
- X-ray Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Lemont, Illinois 60439, United States
| | - Byeongdu Lee
- X-ray Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Lemont, Illinois 60439, United States
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64
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Lee SC, Khalid S, Pollock NL, Knowles TJ, Edler K, Rothnie AJ, R T Thomas O, Dafforn TR. Encapsulated membrane proteins: A simplified system for molecular simulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2549-2557. [PMID: 26946242 DOI: 10.1016/j.bbamem.2016.02.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 12/19/2022]
Abstract
Over the past 50years there has been considerable progress in our understanding of biomolecular interactions at an atomic level. This in turn has allowed molecular simulation methods employing full atomistic modelling at ever larger scales to develop. However, some challenging areas still remain where there is either a lack of atomic resolution structures or where the simulation system is inherently complex. An area where both challenges are present is that of membranes containing membrane proteins. In this review we analyse a new practical approach to membrane protein study that offers a potential new route to high resolution structures and the possibility to simplify simulations. These new approaches collectively recognise that preservation of the interaction between the membrane protein and the lipid bilayer is often essential to maintain structure and function. The new methods preserve these interactions by producing nano-scale disc shaped particles that include bilayer and the chosen protein. Currently two approaches lead in this area: the MSP system that relies on peptides to stabilise the discs, and SMALPs where an amphipathic styrene maleic acid copolymer is used. Both methods greatly enable protein production and hence have the potential to accelerate atomic resolution structure determination as well as providing a simplified format for simulations of membrane protein dynamics. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Sarah C Lee
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Syma Khalid
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Naomi L Pollock
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Tim J Knowles
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Karen Edler
- Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Alice J Rothnie
- School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham B4 7ET, UK
| | - Owen R T Thomas
- School of Chemical Engineering, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Timothy R Dafforn
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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65
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Skar-Gislinge N, Kynde SAR, Denisov IG, Ye X, Lenov I, Sligar SG, Arleth L. Small-angle scattering determination of the shape and localization of human cytochrome P450 embedded in a phospholipid nanodisc environment. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:2412-21. [PMID: 26627649 PMCID: PMC4667284 DOI: 10.1107/s1399004715018702] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 10/05/2015] [Indexed: 11/10/2022]
Abstract
Membrane proteins reconstituted into phospholipid nanodiscs comprise a soluble entity accessible to solution small-angle X-ray scattering (SAXS) studies. It is demonstrated that using SAXS data it is possible to determine both the shape and localization of the membrane protein cytochrome P450 3A4 (CYP3A4) while it is embedded in the phospholipid bilayer of a nanodisc. In order to accomplish this, a hybrid approach to analysis of small-angle scattering data was developed which combines an analytical approach to describe the multi-contrast nanodisc with a free-form bead-model description of the embedded protein. The protein shape is then reconstructed ab initio to optimally fit the data. The result of using this approach is compared with the result obtained using a rigid-body description of the CYP3A4-in-nanodisc system. Here, the CYP3A4 structure relies on detailed information from crystallographic and molecular-dynamics studies of CYP3A4. Both modelling approaches arrive at very similar solutions in which the α-helical anchor of the CYP3A4 systematically stays close to the edge of the nanodisc and with the large catalytic domain leaning over the outer edge of the nanodisc. The obtained distance between the globular domains of CYP3A4 is consistent with previously published theoretical calculations.
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Affiliation(s)
- Nicholas Skar-Gislinge
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Søren A. R. Kynde
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Ilia G. Denisov
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois, 505 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Xin Ye
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois, 505 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Ivan Lenov
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois, 505 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Stephen G. Sligar
- Department of Biochemistry, School of Molecular and Cellular Biology, University of Illinois, 505 South Goodwin Avenue, Urbana, IL 61801, USA
| | - Lise Arleth
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
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66
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Affiliation(s)
- Iwona Siuda
- Department of Biological
Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4, Canada
| | - D. Peter Tieleman
- Department of Biological
Sciences and Centre for Molecular Simulation, University of Calgary, 2500 University Drive North West, Calgary, Alberta T2N 1N4, Canada
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67
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PET/CT Based In Vivo Evaluation of 64Cu Labelled Nanodiscs in Tumor Bearing Mice. PLoS One 2015; 10:e0129310. [PMID: 26132074 PMCID: PMC4488450 DOI: 10.1371/journal.pone.0129310] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/08/2015] [Indexed: 01/05/2023] Open
Abstract
64Cu radiolabelled nanodiscs based on the 11 α-helix MSP1E3D1 protein and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine lipids were, for the first time, followed in vivo by positron emission tomography for evaluating the biodistribution of nanodiscs. A cancer tumor bearing mouse model was used for the investigations, and it was found that the approximately 13 nm nanodiscs, due to their size, permeate deeply into cancer tissue. This makes them promising candidates for both drug delivery purposes and as advanced imaging agents. For the radiolabelling, a simple approach for 64Cu radiolabelling of proteins via a chelating agent, DOTA, was developed. The reaction was performed at sufficiently mild conditions to be compatible with labelling of the protein part of a lipid-protein particle while fully conserving the particle structure including the amphipathic protein fold.
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68
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Maric S, Thygesen MB, Schiller J, Marek M, Moulin M, Haertlein M, Forsyth VT, Bogdanov M, Dowhan W, Arleth L, Pomorski TG. Biosynthetic preparation of selectively deuterated phosphatidylcholine in genetically modified Escherichia coli. Appl Microbiol Biotechnol 2015; 99:241-54. [PMID: 25301578 PMCID: PMC4289089 DOI: 10.1007/s00253-014-6082-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/28/2014] [Accepted: 09/09/2014] [Indexed: 01/07/2023]
Abstract
Phosphatidylcholine (PC) is a major component of eukaryotic cell membranes and one of the most commonly used phospholipids for reconstitution of membrane proteins into carrier systems such as lipid vesicles, micelles and nanodiscs. Selectively deuterated versions of this lipid have many applications, especially in structural studies using techniques such as NMR, neutron reflectivity and small-angle neutron scattering. Here we present a comprehensive study of selective deuteration of phosphatidylcholine through biosynthesis in a genetically modified strain of Escherichia coli. By carefully tuning the deuteration level in E. coli growth media and varying the deuteration of supplemented carbon sources, we show that it is possible to achieve a controlled deuteration for three distinct parts of the PC lipid molecule, namely the (a) lipid head group, (b) glycerol backbone and (c) fatty acyl tail. This biosynthetic approach paves the way for the synthesis of specifically deuterated, physiologically relevant phospholipid species which remain difficult to obtain through standard chemical synthesis.
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Affiliation(s)
- Selma Maric
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
- Center for Membrane Pumps in Cells and Disease, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Mikkel B. Thygesen
- CARB Centre, Department of Chemistry, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Jürgen Schiller
- Institut für Medizinische Physik und Biophysik, Medizinische Fakultät, Universität Leipzig, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Magdalena Marek
- Center for Membrane Pumps in Cells and Disease, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Martine Moulin
- Life Sciences Group, Institut Laue Langevin, 6 rue Jules Horowitz, CEDEX 9, BP156, 38042 Grenoble, France
- Faculty of Natural Sciences & Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
| | - Michael Haertlein
- Life Sciences Group, Institut Laue Langevin, 6 rue Jules Horowitz, CEDEX 9, BP156, 38042 Grenoble, France
| | - V. Trevor Forsyth
- Life Sciences Group, Institut Laue Langevin, 6 rue Jules Horowitz, CEDEX 9, BP156, 38042 Grenoble, France
- Faculty of Natural Sciences & Institute for Science and Technology in Medicine, Keele University, Staffordshire ST5 5BG, UK
| | - Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - William Dowhan
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at Houston, Houston, TX 77030, USA
| | - Lise Arleth
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Thomas Günther Pomorski
- Center for Membrane Pumps in Cells and Disease, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
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69
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Pedersen MC, Hansen SL, Markussen B, Arleth L, Mortensen K. Quantification of the information in small-angle scattering data. J Appl Crystallogr 2014. [DOI: 10.1107/s1600576714024017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Small-angle X-ray and neutron scattering have become increasingly popular owing to improvements in instrumentation and developments in data analysis, sample handling and sample preparation. For some time, it has been suggested that a more systematic approach to the quantification of the information content in small-angle scattering data would allow for a more optimal experiment planning and a more reliable data analysis. In the present article, it is shown how ray-tracing techniques in combination with a statistically rigorous data analysis provide an appropriate platform for such a systematic quantification of the information content in scattering data. As examples of applications, it is shown how the exposure time at different instrumental settings or contrast situations can be optimally prioritized in an experiment. Also, the gain in information by combining small-angle X-ray and neutron scattering is assessed. While solution small-angle scattering data of proteins and protein–lipid complexes are used as examples in the present case study, the approach is generalizable to a wide range of other samples and experimental techniques. The source code for the algorithms and ray-tracing components developed for this study has been made available on-line.
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70
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Midtgaard SR, Pedersen MC, Kirkensgaard JJK, Sørensen KK, Mortensen K, Jensen KJ, Arleth L. Self-assembling peptides form nanodiscs that stabilize membrane proteins. SOFT MATTER 2014; 10:738-752. [PMID: 24651399 DOI: 10.1039/c3sm51727f] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
New methods to handle membrane bound proteins, e.g. G-protein coupled receptors (GPCRs), are highly desirable. Recently, apoliprotein A1 (ApoA1) based lipoprotein particles have emerged as a new platform for studying membrane proteins, and it has been shown that they can self-assemble in combination with phospholipids to form discoidal shaped particles that can stabilize membrane proteins. In the present study, we have investigated an ApoA1 mimetic peptide with respect to its solution structure when in complex with phospholipids. This was achieved using a powerful combination of small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) supported by coarse-grained molecular dynamics simulations. The detailed structure of the discs was determined in unprecedented detail and it was found that they adopt a discoidal structure very similar to the ApoA1 based nanodiscs. We furthermore show that, like the ApoA1 and derived nanodiscs, these peptide discs can accommodate and stabilize a membrane protein. Finally, we exploit their dynamic properties and show that the 18A discs may be used for transferring membrane proteins and associated phospholipids directly and gently into phospholipid nanodiscs.
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71
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Kynde SAR, Skar-Gislinge N, Pedersen MC, Midtgaard SR, Simonsen JB, Schweins R, Mortensen K, Arleth L. Small-angle scattering gives direct structural information about a membrane protein inside a lipid environment. ACTA ACUST UNITED AC 2014; 70:371-83. [PMID: 24531471 DOI: 10.1107/s1399004713028344] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 10/15/2013] [Indexed: 12/11/2022]
Abstract
Monomeric bacteriorhodopsin (bR) reconstituted into POPC/POPG-containing nanodiscs was investigated by combined small-angle neutron and X-ray scattering. A novel hybrid approach to small-angle scattering data analysis was developed. In combination, these provided direct structural insight into membrane-protein localization in the nanodisc and into the protein-lipid interactions. It was found that bR is laterally decentred in the plane of the disc and is slightly tilted in the phospholipid bilayer. The thickness of the bilayer is reduced in response to the incorporation of bR. The observed tilt of bR is in good accordance with previously performed theoretical predictions and computer simulations based on the bR crystal structure. The result is a significant and essential step on the way to developing a general small-angle scattering-based method for determining the low-resolution structures of membrane proteins in physiologically relevant environments.
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Affiliation(s)
- Søren A R Kynde
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark
| | - Nicholas Skar-Gislinge
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark
| | - Martin Cramer Pedersen
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark
| | - Søren Roi Midtgaard
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark
| | - Jens Baek Simonsen
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark
| | | | - Kell Mortensen
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark
| | - Lise Arleth
- Structural Biophysics, Niels Bohr Institute, Faculty of Science, University of Copenhagen, Denmark
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72
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Maric S, Skar-Gislinge N, Midtgaard S, Thygesen MB, Schiller J, Frielinghaus H, Moulin M, Haertlein M, Forsyth VT, Pomorski TG, Arleth L. Stealth carriers for low-resolution structure determination of membrane proteins in solution. ACTA ACUST UNITED AC 2014; 70:317-28. [PMID: 24531466 DOI: 10.1107/s1399004713027466] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 10/07/2013] [Indexed: 02/07/2023]
Abstract
Structural studies of membrane proteins remain a great experimental challenge. Functional reconstitution into artificial nanoscale bilayer disc carriers that mimic the native bilayer environment allows the handling of membrane proteins in solution. This enables the use of small-angle scattering techniques for fast and reliable structural analysis. The difficulty with this approach is that the carrier discs contribute to the measured scattering intensity in a highly nontrivial fashion, making subsequent data analysis challenging. Here, an elegant solution to circumvent the intrinsic complexity brought about by the presence of the carrier disc is presented. In combination with small-angle neutron scattering (SANS) and the D2O/H2O-based solvent contrast-variation method, it is demonstrated that it is possible to prepare specifically deuterated carriers that become invisible to neutrons in 100% D2O at the length scales relevant to SANS. These `stealth' carrier discs may be used as a general platform for low-resolution structural studies of membrane proteins using well established data-analysis tools originally developed for soluble proteins.
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Affiliation(s)
- Selma Maric
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Nicholas Skar-Gislinge
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Søren Midtgaard
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Mikkel B Thygesen
- CARB Centre, Department of Chemistry, University of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Jürgen Schiller
- Institut für Medizinische Physik und Biophysik, Medizinische Fakultät, Universität Leipzig, Härtelstrasse 16-18, 04107 Leipzig, Germany
| | - Henrich Frielinghaus
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Scattering, TUM FRM-2, Lichtenbergstrasse 1, 85747 Garching, Germany
| | - Martine Moulin
- Life Sciences Group, Institut Laue-Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France
| | - Michael Haertlein
- Life Sciences Group, Institut Laue-Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France
| | - V Trevor Forsyth
- Life Sciences Group, Institut Laue-Langevin, 6 Rue Jules Horowitz, 38042 Grenoble, France
| | - Thomas Günther Pomorski
- Center for Membrane Pumps in Cells and Disease, Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, Frederiksberg C, Denmark
| | - Lise Arleth
- Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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73
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Pedersen MC, Arleth L, Mortensen K. WillItFit: a framework for fitting of constrained models to small-angle scattering data. J Appl Crystallogr 2013. [DOI: 10.1107/s0021889813026022] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A software framework for analysis of small-angle scattering data is presented. On the basis of molecular constraints and prior knowledge of the chemical composition of the sample, the software is capable of simultaneously fitting small-angle X-ray and neutron scattering data to analytical or semi-analytical models of biomacromolecules. The software features various fitting routines along with the possibility of incorporating instrumental resolution effects on the fit. Finally, trust region estimation, based on the profile likelihood strategy, is implemented. The algorithms and models are written in C, whereas the user interface is written in Python. Parallelization is implemented using the OpenMP extensions to C. The source code is available for free upon request orviathe associated code repository. The software runs on Linux, Windows and OSX and is available as an open-source initiative published under the General Publishing License.
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74
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Dai H, Hong B, Xu Z, Ma L, Chen Y, Xiao Y, Wu R. Nuclear magnetic resonance spectroscopy is highly sensitive for lipid-soluble metabolites. Neural Regen Res 2013; 8:2103-10. [PMID: 25206519 PMCID: PMC4146060 DOI: 10.3969/j.issn.1673-5374.2013.22.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 03/25/2013] [Indexed: 02/05/2023] Open
Abstract
Although the water-soluble metabolite profile of human mesenchymal stem cells is known, the lipid profile still needs further investigation. In this study, methanol-chloroform was used to extract pid-soluble metabolites and perchloric acid was used to extract water-soluble metabolites. Furthermore, a dual phase extraction method using methanol-chloroform and water was used to obtain both water and lipid fractions simultaneously. All metabolite extractions were analyzed on a 9.4T high-resolution nuclear magnetic resonance spectrometer. Metabolite resonance peaks were assigned in the acquired spectra according to the chemical shift, and the extraction efficiency of ferent methods was compared. Results showed that in the spectra of water-soluble extracts, major metabolites comprised low molecular weight metabolites, including lactate, acetic acid, fatty acids, threonine, glutamic acid, creatine, choline and its derivatives, while in the spectra of lipid-soluble extracts, most metabolites were assigned to fatty acids. Among the different extraction procedures, perchloric acid was more efficient in extracting water-soluble metabolites and methanol-chloroform was efficient in extracting organic components compared with the dual phase extraction method. Nuclear magnetic resonance spectroscopy showed that as low as 0.7 mg organic yield was enough to obtain clear resonance peaks, while about 6.0 mg water-soluble yield was needed to obtain relatively favorable spectral lines. These results show that the efficiency of extracting water and lipid fractions is higher using perchloric acid and methanol-chloroform compared with dual phase extraction and that nuclear magnetic resonance spectroscopy is highly sensitive for analyzing lipid-soluble extracts.
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Affiliation(s)
- Haiyang Dai
- Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041; Department of Medical Imaging, Huizhou Municipal Central Hospital, Huizhou 516001, Guangdong Province, China
- Department of Radiology, the First People's Hospital of Foshan, Foshan 528000, Guangdong Province, China
| | - Bikai Hong
- Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041; Department of Medical Imaging, Huizhou Municipal Central Hospital, Huizhou 516001, Guangdong Province, China
| | - Zhifeng Xu
- Department of Pediatrics, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Lian Ma
- Central Laboratory, Shantou University, Shantou 515041, Guangdong Province, China
| | - Yaowen Chen
- Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Yeyu Xiao
- Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041; Department of Medical Imaging, Huizhou Municipal Central Hospital, Huizhou 516001, Guangdong Province, China
- Corresponding author: Yeyu Xiao, Master, Professor, Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China, . Renhua Wu, M.D., Professor, Doctoral supervisor, Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China, (N20120517004)
| | - Renhua Wu
- Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041; Department of Medical Imaging, Huizhou Municipal Central Hospital, Huizhou 516001, Guangdong Province, China
- Corresponding author: Yeyu Xiao, Master, Professor, Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China, . Renhua Wu, M.D., Professor, Doctoral supervisor, Department of Medical Imaging, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China, (N20120517004)
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75
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Kel O, Tamimi A, Thielges MC, Fayer MD. Ultrafast Structural Dynamics Inside Planar Phospholipid Multibilayer Model Cell Membranes Measured with 2D IR Spectroscopy. J Am Chem Soc 2013; 135:11063-74. [DOI: 10.1021/ja403675x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Oksana Kel
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Amr Tamimi
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Megan C. Thielges
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Michael D. Fayer
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
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76
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Justesen BH, Hansen RW, Martens HJ, Theorin L, Palmgren MG, Martinez KL, Pomorski TG, Fuglsang AT. Active plasma membrane P-type H+-ATPase reconstituted into nanodiscs is a monomer. J Biol Chem 2013; 288:26419-29. [PMID: 23836891 DOI: 10.1074/jbc.m112.446948] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Plasma membrane H(+)-ATPases form a subfamily of P-type ATPases responsible for pumping protons out of cells and are essential for establishing and maintaining the crucial transmembrane proton gradient in plants and fungi. Here, we report the reconstitution of the Arabidopsis thaliana plasma membrane H(+)-ATPase isoform 2 into soluble nanoscale lipid bilayers, also termed nanodiscs. Based on native gel analysis and cross-linking studies, the pump inserts into nanodiscs as a functional monomer. Insertion of the H(+)-ATPase into nanodiscs has the potential to enable structural and functional characterization using techniques normally applicable only for soluble proteins.
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77
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Breyton C, Gabel F, Lethier M, Flayhan A, Durand G, Jault JM, Juillan-Binard C, Imbert L, Moulin M, Ravaud S, Härtlein M, Ebel C. Small angle neutron scattering for the study of solubilised membrane proteins. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:71. [PMID: 23852580 DOI: 10.1140/epje/i2013-13071-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/22/2013] [Accepted: 05/16/2013] [Indexed: 06/02/2023]
Abstract
Small angle neutron scattering (SANS) is a powerful technique for investigating association states and conformational changes of biological macromolecules in solution. SANS is of particular interest for the study of the multi-component systems, as membrane protein complexes, for which in vitro characterisation and structure determination are often difficult. This article details the important physical properties of surfactants in view of small angle neutron scattering studies and the interest to deuterate membrane proteins for contrast variation studies. We present strategies for the production of deuterated membrane proteins and methods for quality control. We then review some studies on membrane proteins, and focus on the strategies to overcome the intrinsic difficulty to eliminate homogeneously the detergent or surfactant signal for solubilised membrane proteins, or that of lipids for membrane proteins inserted in liposomes.
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Affiliation(s)
- Cécile Breyton
- Univ. Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38027, Grenoble, France
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78
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Xu XP, Zhai D, Kim E, Swift M, Reed JC, Volkmann N, Hanein D. Three-dimensional structure of Bax-mediated pores in membrane bilayers. Cell Death Dis 2013; 4:e683. [PMID: 23788040 PMCID: PMC3702287 DOI: 10.1038/cddis.2013.210] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax) is a member of the Bcl-2 protein family having a pivotal role in triggering cell commitment to apoptosis. Bax is latent and monomeric in the cytosol but transforms into its lethal, mitochondria-embedded oligomeric form in response to cell stress, leading to the release of apoptogenic factors such as cytochrome C. Here, we dissected the structural correlates of Bax membrane insertion while oligomerization is halted. This strategy was enabled through the use of nanometer-scale phospholipid bilayer islands (nanodiscs) the size of which restricts the reconstituted system to single Bax-molecule activity. Using this minimal reconstituted system, we captured structural correlates that precede Bax homo-oligomerization elucidating previously inaccessible steps of the core molecular mechanism by which Bcl-2 family proteins regulate membrane permeabilization. We observe that, in the presence of BH3 interacting domain death agonist (Bid) BH3 peptide, Bax monomers induce the formation of ~3.5-nm diameter pores and significantly distort the phospholipid bilayer. These pores are compatible with promoting release of ions as well as proteinaceous components, suggesting that membrane-integrated Bax monomers in the presence of Bid BH3 peptides are key functional units for the activation of the cell demolition machinery.
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Affiliation(s)
- X-P Xu
- Bioinformatics and Systems Biology Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA
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79
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Pan J, Heberle FA, Petruzielo RS, Katsaras J. Using small-angle neutron scattering to detect nanoscopic lipid domains. Chem Phys Lipids 2013; 170-171:19-32. [PMID: 23518250 DOI: 10.1016/j.chemphyslip.2013.02.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 02/27/2013] [Accepted: 02/28/2013] [Indexed: 11/25/2022]
Abstract
The cell plasma membrane is a complex system, which is thought to be capable of exhibiting non-random lateral organization. Studies of live cells and model membranes have yielded mechanisms responsible for the formation, growth, and maintenance of nanoscopic heterogeneities, although the existence and mechanisms that give rise to these heterogeneities remain controversial. Small-angle neutron scattering (SANS) is a tool ideally suited to interrogate lateral heterogeneity in model membranes, primarily due to its unique spatial resolution (i.e., ~5-100nm) and its ability to resolve structure with minimal perturbation to the membrane. In this review we examine several methods used to analyze the SANS signal arising from freely suspended unilamellar vesicles containing lateral heterogeneity. Specifically, we discuss an analytical model for a single, round domain on a spherical vesicle. We then discuss a numerical method that uses Monte Carlo simulation to describe systems with multiple domains and/or more complicated morphologies. Also discussed are several model-independent approaches that are sensitive to membrane heterogeneity. The review concludes with several recent applications of SANS to the study of membrane raft mixtures.
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Affiliation(s)
- Jianjun Pan
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
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80
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Wadsäter M, Barker R, Mortensen K, Feidenhans'l R, Cárdenas M. Effect of phospholipid composition and phase on nanodisc films at the solid-liquid interface as studied by neutron reflectivity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:2871-2880. [PMID: 23373466 DOI: 10.1021/la3024698] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Nanodiscs are disc-like self-assembled structures formed by phospholipids and amphipatic proteins. The proteins wrap like a belt around the hydrophobic part of the lipids, basically producing nanometer-sized patches of lipid bilayers. The bilayer in the nanodisc constitutes a native-like model of the cell membrane and can act as a nanometer-sized container for functional single membrane proteins. In this study, we present a general nanodisc-based system, intended for structural and functional studies of membrane proteins. In this method, the nanodiscs are aligned at a solid surface, providing the ability to determine the average structure of the film along an axis perpendicular to the interface as measured by neutron reflectivity. The nanodisc film was optimized in terms of nanodisc coverage, reduced film roughness, and stability for time-consuming studies. This was achieved by a systematic variation of the lipid phase, charge, and length of lipid tails. Herein, we show that, although all studied nanodiscs align with their lipid bilayer parallel to the interface, gel-phase DMPC nanodiscs form the most suitable film for future membrane protein studies since they yield a dense irreversibly adsorbed film with low roughness and high stability over time. This may be explained by the appropriate matching between the thickness of the hydrophobic lipid core of gel phase DMPC and the height of the belt protein. Moreover, once formed the gel-phase DMPC nanodiscs film can be heated up to melt the lipid bilayer, thus providing a more biologically friendly environment for membrane proteins.
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Affiliation(s)
- Maria Wadsäter
- Nano-Science Center and Institute of Chemistry, University of Copenhagen, Copenhagen, Denmark
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81
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Laursen T, Naur P, Møller BL. Amphipol trapping of a functional CYP system. Biotechnol Appl Biochem 2013; 60:119-27. [DOI: 10.1002/bab.1092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/03/2013] [Indexed: 01/29/2023]
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82
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Cell-free protein synthesis of membrane (1,3)-β-d-glucan (curdlan) synthase: co-translational insertion in liposomes and reconstitution in nanodiscs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:743-57. [PMID: 23063656 DOI: 10.1016/j.bbamem.2012.10.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 09/25/2012] [Accepted: 10/04/2012] [Indexed: 01/07/2023]
Abstract
A membrane-embedded curdlan synthase (CrdS) from Agrobacterium is believed to catalyse a repetitive addition of glucosyl residues from UDP-glucose to produce the (1,3)-β-d-glucan (curdlan) polymer. We report wheat germ cell-free protein synthesis (WG-CFPS) of full-length CrdS containing a 6xHis affinity tag and either Factor Xa or Tobacco Etch Virus proteolytic sites, using a variety of hydrophobic membrane-mimicking environments. Full-length CrdS was synthesised with no variations in primary structure, following analysis of tryptic fragments by MALDI-TOF/TOF Mass Spectrometry. Preparative scale WG-CFPS in dialysis mode with Brij-58 yielded CrdS in mg/ml quantities. Analysis of structural and functional properties of CrdS during protein synthesis showed that CrdS was co-translationally inserted in DMPC liposomes during WG-CFPS, and these liposomes could be purified in a single step by density gradient floatation. Incorporated CrdS exhibited a random orientation topology. Following affinity purification of CrdS, the protein was reconstituted in nanodiscs with Escherichia coli lipids or POPC and a membrane scaffold protein MSP1E3D1. CrdS nanodiscs were characterised by small-angle X-ray scattering using synchrotron radiation and the data obtained were consistent with insertion of CrdS into bilayers. We found CrdS synthesised in the presence of the Ac-AAAAAAD surfactant peptide or co-translationally inserted in liposomes made from E. coli lipids to be catalytically competent. Conversely, CrdS synthesised with only Brij-58 was inactive. Our findings pave the way for future structural studies of this industrially important catalytic membrane protein.
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83
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Wadsäter M, Laursen T, Singha A, Hatzakis NS, Stamou D, Barker R, Mortensen K, Feidenhans'l R, Møller BL, Cárdenas M. Monitoring shifts in the conformation equilibrium of the membrane protein cytochrome P450 reductase (POR) in nanodiscs. J Biol Chem 2012; 287:34596-603. [PMID: 22891242 PMCID: PMC3464565 DOI: 10.1074/jbc.m112.400085] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/09/2012] [Indexed: 11/06/2022] Open
Abstract
Nanodiscs are self-assembled ∼50-nm(2) patches of lipid bilayers stabilized by amphipathic belt proteins. We demonstrate that a well ordered dense film of nanodiscs serves for non-destructive, label-free studies of isolated membrane proteins in a native like environment using neutron reflectometry (NR). This method exceeds studies of membrane proteins in vesicle or supported lipid bilayer because membrane proteins can be selectively adsorbed with controlled orientation. As a proof of concept, the mechanism of action of the membrane-anchored cytochrome P450 reductase (POR) is studied here. This enzyme is responsible for catalyzing the transfer of electrons from NADPH to cytochrome P450s and thus is a key enzyme in the biosynthesis of numerous primary and secondary metabolites in plants. Neutron reflectometry shows a coexistence of two different POR conformations, a compact and an extended form with a thickness of 44 and 79 Å, respectively. Upon complete reduction by NADPH, the conformational equilibrium shifts toward the compact form protecting the reduced FMN cofactor from engaging in unspecific electron transfer reaction.
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Affiliation(s)
- Maria Wadsäter
- From the Nano-Science Center and Institute of Chemistry, Faculty of Science, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Tomas Laursen
- the Plant Biochemistry Laboratory, Department of Plant and Environmental Science, Faculty of Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Aparajita Singha
- the Bio-Nanotechnology Laboratory, Department of Neuroscience and Pharmacology, Nano-Science Center, Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Nikos S. Hatzakis
- the Bio-Nanotechnology Laboratory, Department of Chemistry, Department of Neuroscience and Pharmacology, Nano-Science Center, Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Dimitrios Stamou
- the Bio-Nanotechnology Laboratory, Department of Chemistry, Department of Neuroscience and Pharmacology, Nano-Science Center, Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Robert Barker
- the Institut Laue Langevin, 6 rue Jules Horowitz – BP 156, 38042 Grenoble Cedex 9, France, and
| | - Kell Mortensen
- the Nano-Science Center and Niels Bohr Institute, Universitetsparken 5, 2200 Copenhagen, Denmark
| | - Robert Feidenhans'l
- the Nano-Science Center and Niels Bohr Institute, Universitetsparken 5, 2200 Copenhagen, Denmark
| | - Birger Lindberg Møller
- the Plant Biochemistry Laboratory, Department of Plant and Environmental Science, Faculty of Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Marité Cárdenas
- From the Nano-Science Center and Institute of Chemistry, Faculty of Science, University of Copenhagen, DK-2200 Copenhagen, Denmark
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84
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Cho EC. A Facile Synthesis of Discoidal Lipid Bilayer Nanostructure by Association of a Cationic Amphiphilic Polyelectrolyte. B KOREAN CHEM SOC 2012. [DOI: 10.5012/bkcs.2012.33.7.2187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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85
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Berthaud A, Manzi J, Pérez J, Mangenot S. Modeling detergent organization around aquaporin-0 using small-angle X-ray scattering. J Am Chem Soc 2012; 134:10080-8. [PMID: 22621369 DOI: 10.1021/ja301667n] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Solubilization of integral membrane proteins in aqueous solutions requires the presence of amphiphilic molecules like detergents. The transmembrane region of the proteins is then surrounded by a corona formed by these molecules, ensuring a hydrophilic outer surface. The presence of this corona has strongly hampered structural studies of solubilized membrane proteins by small-angle X-ray scattering (SAXS), a technique frequently used to monitor conformational changes of soluble proteins. Through the online combination of size exclusion chromatography, SAXS, and refractometry, we have determined a precise geometrical model of the n-dodecyl β-d-maltopyranoside corona surrounding aquaporin-0, the most abundant membrane protein of the eye lens. The SAXS data were well-fitted by a detergent corona shaped in an elliptical toroid around the crystal structure of the protein, similar to the elliptical shape recently reported for nanodiscs (Skar-Gislinge et al. J. Am. Chem. Soc. 2010, 132, 13713-13722). The torus thickness determined from the curve-fitting protocol is in excellent agreement with the thickness of a lipid bilayer, while the number of detergent molecules deduced from the volume of the torus compares well with those obtained on the same sample from refractometry and mass analysis based on SAXS forward scattering. For the first time, the partial specific volume of the detergent surrounding a protein was measured. The present protocol is a crucial step toward future conformational studies of membrane proteins in solution.
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Affiliation(s)
- Alice Berthaud
- Institut Curie, Centre de Recherche, CNRS UMR168, Université Pierre et Marie Curie, F-75248 Paris Cedex, France
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86
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Murakami T. Phospholipid nanodisc engineering for drug delivery systems. Biotechnol J 2012; 7:762-7. [DOI: 10.1002/biot.201100508] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2011] [Revised: 03/05/2012] [Accepted: 03/28/2012] [Indexed: 11/05/2022]
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87
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Wadsäter M, Simonsen JB, Lauridsen T, Tveten EG, Naur P, Bjørnholm T, Wacklin H, Mortensen K, Arleth L, Feidenhans'l R, Cárdenas M. Aligning nanodiscs at the air-water interface, a neutron reflectivity study. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:15065-15073. [PMID: 22047603 DOI: 10.1021/la203100n] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nanodiscs are self-assembled nanostructures composed of a belt protein and a small patch of lipid bilayer, which can solubilize membrane proteins in a lipid bilayer environment. We present a method for the alignment of a well-defined two-dimensional layer of nanodiscs at the air-water interface by careful design of an insoluble surfactant monolayer at the surface. We used neutron reflectivity to demonstrate the feasibility of this approach and to elucidate the structure of the nanodisc layer. The proof of concept is hereby presented with the use of nanodiscs composed of a mixture of two different lipid (DMPC and DMPG) types to obtain a net overall negative charge of the nanodiscs. We find that the nanodisc layer has a thickness or 40.9 ± 2.6 Å with a surface coverage of 66 ± 4%. This layer is located about 15 Å below a cationic surfactant layer at the air-water interface. The high level of organization within the nanodiscs layer is reflected by a low interfacial roughness (~4.5 Å) found. The use of the nanodisc as a biomimetic model of the cell membrane allows for studies of single membrane proteins isolated in a confined lipid environment. The 2D alignment of nanodiscs could therefore enable studies of high-density layers containing membrane proteins that, in contrast to membrane proteins reconstituted in a continuous lipid bilayer, remain isolated from influences of neighboring membrane proteins within the layer.
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Affiliation(s)
- Maria Wadsäter
- Nano-Science Center and Institute of Chemistry, Faculty of Life Sciences, University of Copenhagen, Copenhagen, Denmark.
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88
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Kawai T, Caaveiro JM, Abe R, Katagiri T, Tsumoto K. Catalytic activity of MsbA reconstituted in nanodisc particles is modulated by remote interactions with the bilayer. FEBS Lett 2011; 585:3533-7. [DOI: 10.1016/j.febslet.2011.10.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 09/29/2011] [Accepted: 10/07/2011] [Indexed: 11/26/2022]
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89
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Evrard G, Mareuil F, Bontems F, Sizun C, Perez J. DADIMODO: a program for refining the structure of multidomain proteins and complexes against small-angle scattering data and NMR-derived restraints. J Appl Crystallogr 2011. [DOI: 10.1107/s0021889811035758] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
DADIMODOis a program for refining atomic models of multidomain proteins or complexes against small-angle X-ray scattering data. Interdomain distance and orientational restraints, such as those derived from NMR measurements, can be included in the optimization process. While domain structures are mainly kept rigid, flexible regions can be user defined. Stepwise generic conformational changes, specified by the user, are applied cyclically in a stochastic optimization algorithm that performs a search in the protein conformation space. The convergence for this genetic algorithm is driven by an adaptable selection pressure. The algorithmic structure guarantees that a physically acceptable full atomic model of the structure is present at all stages of the optimization. A graphical user interface ensures user-friendly handling.
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90
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91
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Halsey CM, Oshokoya OO, Jiji RD, Cooley JW. Deep-UV Resonance Raman Analysis of theRhodobacter capsulatusCytochromebc1Complex Reveals a Potential Marker for the Transmembrane Peptide Backbone. Biochemistry 2011; 50:6531-8. [DOI: 10.1021/bi200596w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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92
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Morgan CR, Hebling CM, Rand KD, Stafford DW, Jorgenson JW, Engen JR. Conformational transitions in the membrane scaffold protein of phospholipid bilayer nanodiscs. Mol Cell Proteomics 2011; 10:M111.010876. [PMID: 21715319 DOI: 10.1074/mcp.m111.010876] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Phospholipid bilayer nanodiscs are model membrane systems that provide an environment where membrane proteins are highly stable and monodisperse without the use of detergents or liposomes. Nanodiscs consist of a discoidal phospholipid bilayer encircled by two copies of an amphipathic alpha helical membrane scaffold protein, which is modeled from apolipoprotein A-1. Hydrogen exchange mass spectrometry was used to probe the structure and dynamics of the scaffold protein in the presence and absence of lipid. On nanodisc self-assembly, the entire scaffold protein gained significant protection from exchange, consistent with a large, protein-wide, structural rearrangement. This protection was short-lived and the scaffold protein was highly deuterated within 2 h. Several regions of the scaffold protein, in both the lipid-free and lipid-associated states, displayed EX1 unfolding kinetics. The rapid deuteration of the scaffold protein and the presence of correlated unfolding events both indicate that nanodiscs are dynamic rather than rigid bodies in solution. This work provides a catalog of the expected scaffold protein peptic peptides in a nanodisc-hydrogen exchange mass spectrometry experiment and their deuterium uptake signatures, data that can be used as a benchmark to verify correct assembly and nanodisc structure. Such reference data will be useful control data for all hydrogen exchange mass spectrometry experiments involving nanodiscs in which transmembrane or lipid-associated proteins are the primary molecule(s) of interest.
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Affiliation(s)
- Christopher R Morgan
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
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93
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Skar-Gislinge N, Arleth L. Small-angle scattering from phospholipid nanodiscs: derivation and refinement of a molecular constrained analytical model form factor. Phys Chem Chem Phys 2011; 13:3161-70. [DOI: 10.1039/c0cp01074j] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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94
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Ryan RO. Nanobiotechnology applications of reconstituted high density lipoprotein. J Nanobiotechnology 2010; 8:28. [PMID: 21122135 PMCID: PMC3004818 DOI: 10.1186/1477-3155-8-28] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 12/01/2010] [Indexed: 01/23/2023] Open
Abstract
High-density lipoprotein (HDL) plays a fundamental role in the Reverse Cholesterol Transport pathway. Prior to maturation, nascent HDL exist as disk-shaped phospholipid bilayers whose perimeter is stabilized by amphipathic apolipoproteins. Methods have been developed to generate reconstituted (rHDL) in vitro and these particles have been used in a variety of novel ways. To differentiate between physiological HDL particles and non-natural rHDL that have been engineered to possess additional components/functions, the term nanodisk (ND) is used. In this review, various applications of ND technology are described, such as their use as miniature membranes for solubilization and characterization of integral membrane proteins in a native like conformation. In other work, ND harboring hydrophobic biomolecules/drugs have been generated and used as transport/delivery vehicles. In vitro and in vivo studies show that drug loaded ND are stable and possess potent biological activity. A third application of ND is their use as a platform for incorporation of amphiphilic chelators of contrast agents, such as gadolinium, used in magnetic resonance imaging. Thus, it is demonstrated that the basic building block of plasma HDL can be repurposed for alternate functions.
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Affiliation(s)
- Robert O Ryan
- Center for Prevention of Obesity, Cardiovascular Disease and Diabetes, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr, Way, Oakland CA 94609, USA.
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95
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Laursen T, Jensen K, Møller BL. Conformational changes of the NADPH-dependent cytochrome P450 reductase in the course of electron transfer to cytochromes P450. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:132-8. [PMID: 20624491 DOI: 10.1016/j.bbapap.2010.07.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/09/2010] [Accepted: 07/01/2010] [Indexed: 01/18/2023]
Abstract
The NADPH-dependent cytochrome P450 reductase (CPR) is a key electron donor to eucaryotic cytochromes P450 (CYPs). CPR shuttles electrons from NADPH through the FAD and FMN-coenzymes into the iron of the prosthetic heme-group of the CYP. In the course of these electron transfer reactions, CPR undergoes large conformational changes. This mini-review discusses the new evidence provided for such conformational changes involving a combination of a "swinging" and "rotating" model and highlights the molecular mechanisms by which formation of these conformations are controlled and thereby enables CPR to serve as an effective electron transferring "nano-machine".
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Affiliation(s)
- Tomas Laursen
- Plant Biochemistry Laboratory, Department of Plant Biology and Biotechnology, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
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