1
|
Hajizadeh M, Golub M, Moldenhauer M, Matsarskaia O, Martel A, Porcar L, Maksimov E, Friedrich T, Pieper J. Solution Structures of Two Different FRP-OCP Complexes as Revealed via SEC-SANS. Int J Mol Sci 2024; 25:2781. [PMID: 38474026 DOI: 10.3390/ijms25052781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/02/2024] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Photosynthetic organisms have established photoprotective mechanisms in order to dissipate excess light energy into heat, which is commonly known as non-photochemical quenching. Cyanobacteria utilize the orange carotenoid protein (OCP) as a high-light sensor and quencher to regulate the energy flow in the photosynthetic apparatus. Triggered by strong light, OCP undergoes conformational changes to form the active red state (OCPR). In many cyanobacteria, the back conversion of OCP to the dark-adapted state is assisted by the fluorescence recovery protein (FRP). However, the exact molecular events involving OCP and its interaction with FRP remain largely unraveled so far due to their metastability. Here, we use small-angle neutron scattering combined with size exclusion chromatography (SEC-SANS) to unravel the solution structures of FRP-OCP complexes using a compact mutant of OCP lacking the N-terminal extension (∆NTEOCPO) and wild-type FRP. The results are consistent with the simultaneous presence of stable 2:2 and 2:1 FRP-∆NTEOCPO complexes in solution, where the former complex type is observed for the first time. For both complex types, we provide ab initio low-resolution shape reconstructions and compare them to homology models based on available crystal structures. It is likely that both complexes represent intermediate states of the back conversion of OCP to its dark-adapted state in the presence of FRP, which are of transient nature in the photocycle of wild-type OCP. This study demonstrates the large potential of SEC-SANS in revealing the solution structures of protein complexes in polydisperse solutions that would otherwise be averaged, leading to unspecific results.
Collapse
Affiliation(s)
- Mina Hajizadeh
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411 Tartu, Estonia
| | - Maksym Golub
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411 Tartu, Estonia
| | - Marcus Moldenhauer
- Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Olga Matsarskaia
- Institut Laue-Langevin, Avenue des Martyrs 71, CEDEX 9, 38042 Grenoble, France
| | - Anne Martel
- Institut Laue-Langevin, Avenue des Martyrs 71, CEDEX 9, 38042 Grenoble, France
| | - Lionel Porcar
- Institut Laue-Langevin, Avenue des Martyrs 71, CEDEX 9, 38042 Grenoble, France
| | - Eugene Maksimov
- Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119991 Moscow, Russia
| | - Thomas Friedrich
- Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, W. Ostwald Str. 1, 50411 Tartu, Estonia
| |
Collapse
|
2
|
Golub M, Pieper J. Recent Progress in Solution Structure Studies of Photosynthetic Proteins Using Small-Angle Scattering Methods. Molecules 2023; 28:7414. [PMID: 37959833 PMCID: PMC10650700 DOI: 10.3390/molecules28217414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Utilized for gaining structural insights, small-angle neutron and X-ray scattering techniques (SANS and SAXS, respectively) enable an examination of biomolecules, including photosynthetic pigment-protein complexes, in solution at physiological temperatures. These methods can be seen as instrumental bridges between the high-resolution structural information achieved by crystallography or cryo-electron microscopy and functional explorations conducted in a solution state. The review starts with a comprehensive overview about the fundamental principles and applications of SANS and SAXS, with a particular focus on the recent advancements permitting to enhance the efficiency of these techniques in photosynthesis research. Among the recent developments discussed are: (i) the advent of novel modeling tools whereby a direct connection between SANS and SAXS data and high-resolution structures is created; (ii) the employment of selective deuteration, which is utilized to enhance spatial selectivity and contrast matching; (iii) the potential symbioses with molecular dynamics simulations; and (iv) the amalgamations with functional studies that are conducted to unearth structure-function relationships. Finally, reference is made to time-resolved SANS/SAXS experiments, which enable the monitoring of large-scale structural transformations of proteins in a real-time framework.
Collapse
Affiliation(s)
| | - Jörg Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwald Str. 1, 50411 Tartu, Estonia;
| |
Collapse
|
3
|
Golub M, Moldenhauer M, Matsarskaia O, Martel A, Grudinin S, Soloviov D, Kuklin A, Maksimov EG, Friedrich T, Pieper J. Stages of OCP-FRP Interactions in the Regulation of Photoprotection in Cyanobacteria, Part 2: Small-Angle Neutron Scattering with Partial Deuteration. J Phys Chem B 2023; 127:1901-1913. [PMID: 36815674 DOI: 10.1021/acs.jpcb.2c07182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
We used small-angle neutron scattering partially coupled with size-exclusion chromatography to unravel the solution structures of two variants of the Orange Carotenoid Protein (OCP) lacking the N-terminal extension (OCP-ΔNTE) and its complex formation with the Fluorescence Recovery Protein (FRP). The dark-adapted, orange form OCP-ΔNTEO is fully photoswitchable and preferentially binds the pigment echinenone. Its complex with FRP consists of a monomeric OCP component, which closely resembles the compact structure expected for the OCP ground state, OCPO. In contrast, the pink form OCP-ΔNTEP, preferentially binding the pigment canthaxanthin, is mostly nonswitchable. The pink OCP form appears to occur as a dimer and is characterized by a separation of the N- and C-terminal domains, with the canthaxanthin embedded only into the N-terminal domain. Therefore, OCP-ΔNTEP can be viewed as a prototypical model system for the active, spectrally red-shifted state of OCP, OCPR. The dimeric structure of OCP-ΔNTEP is retained in its complex with FRP. Small-angle neutron scattering using partially deuterated OCP-FRP complexes reveals that FRP undergoes significant structural changes upon complex formation with OCP. The observed structures are assigned to individual intermediates of the OCP photocycle in the presence of FRP.
Collapse
Affiliation(s)
- Maksym Golub
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia
| | - Marcus Moldenhauer
- Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Olga Matsarskaia
- Institut Laue-Langevin, Avenue des Martyrs 71, 38042 Cedex 9 Grenoble, France
| | - Anne Martel
- Institut Laue-Langevin, Avenue des Martyrs 71, 38042 Cedex 9 Grenoble, France
| | - Sergei Grudinin
- Université Grenoble Alpes, CNRS, Grenoble INP, LJK, 38000 Grenoble, France
| | - Dmytro Soloviov
- Faculty of Physics, Adam Mickiewicz University, ul. Wieniawskiego 1, 61-712 Poznan, Poland.,Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, Kirova 36a, 07270 Chornobyl, Ukraine
| | - Alexander Kuklin
- Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna, Russia.,Moscow Institute of Physics and Technology, Institutskiy per. 9, 141701 Dolgoprudny, Russia
| | - Eugene G Maksimov
- Department of Biophysics, M. V. Lomonosov Moscow State University, Vorob'jovy Gory 1-12, 119899 Moscow, Russia
| | - Thomas Friedrich
- Institute of Chemistry PC 14, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, 50411 Tartu, Estonia
| |
Collapse
|
4
|
Tang-Siegel GG. Human Serum Mediated Bacteriophage Life Cycle Switch in Aggregatibacter actinomycetemcomitans Is Linked to Pyruvate Dehydrogenase Complex. Life (Basel) 2023; 13:436. [PMID: 36836793 PMCID: PMC9959103 DOI: 10.3390/life13020436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Antimicrobial resistance is rising as a major global public health threat and antibiotic resistance genes are widely spread among species, including human oral pathogens, e.g., Aggregatibacter actinomycetemcomitans. This Gram-negative, capnophilic, facultative anaerobe is well recognized as a causative agent leading to periodontal diseases, as well as seriously systemic infections including endocarditis. A. actinomycetemcomitans has also evolved mechanisms against complement-mediated phagocytosis and resiliently survives in serum-rich in vivo environments, i.e., inflamed periodontal pockets and blood circulations. This bacterium, however, demonstrated increasing sensitivity to human serum, when being infected by a pseudolysogenic bacteriophage S1249, which switched to the lytic state as a response to human serum. Concomitantly, the pyruvate dehydrogenase complex (PDHc), which is composed of multiple copies of three enzymes (E1, E2, and E3) and oxidatively decarboxylates pyruvate to acetyl-CoA available for tricarboxylic acid (TCA) cycle, was found up-regulated 10-fold in the bacterial lysogen after human serum exposure. The data clearly indicated that certain human serum components induced phage virion replication and egress, resulting in bacterial lysis. Phage manipulation of bacterial ATP production through regulation of PDHc, a gatekeeper linking glycolysis to TCA cycle through aerobic respiration, suggests that a more efficient energy production and delivery system is required for phage progeny replication and release in this in vivo environment. Insights into bacteriophage regulation of bacterial fitness in a mimic in vivo condition will provide alternative strategies to control bacterial infection, in addition to antibiotics.
Collapse
Affiliation(s)
- Gaoyan Grace Tang-Siegel
- Department of Molecular Physiology and Biophysics, College of Medicine, University of Vermont and State Agricultural College, Burlington, VT 05405, USA
| |
Collapse
|
5
|
Brady NG, Qian S, Nguyen J, O'Neill HM, Bruce BD. Small angle neutron scattering and lipidomic analysis of a native, trimeric PSI-SMALP from a thermophilic cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2022; 1863:148596. [PMID: 35853496 PMCID: PMC10228149 DOI: 10.1016/j.bbabio.2022.148596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 06/05/2022] [Accepted: 07/11/2022] [Indexed: 01/21/2023]
Abstract
The use of styrene-maleic acid copolymers (SMAs) to produce membrane protein-containing nanodiscs without the initial detergent isolation has gained significant interest over the last decade. We have previously shown that a Photosystem I SMALP from the thermophilic cyanobacterium, Thermosynechococcus elongatus (PSI-SMALP), has much more rapid energy transfer and charge separation in vitro than detergent isolated PSI complexes. In this study, we have utilized small-angle neutron scattering (SANS) to better understand the geometry of these SMALPs. These techniques allow us to investigate the size and shape of these particles in their fully solvated state. Further, the particle's proteolipid core and detergent shell or copolymer belt can be interrogated separately using contrast variation, a capability unique to SANS. Here we report the dimensions of the Thermosynechococcus elongatus PSI-SMALP containing a PSI trimer. At ~1.5 MDa, PSI-SMALP is the largest SMALP to be isolated; our lipidomic analysis indicates it contains ~1300 lipids/per trimeric particle, >40-fold more than the PSI-DDM particle and > 100 fold more than identified in the 1JB0 crystal structure. Interestingly, the lipid composition to the PSI trimer in the PSI-SMALP differs significantly from bulk thylakoid composition, being enriched ~50 % in the anionic sulfolipid, SQDG. Finally, utilizing the contrast match point for the SMA 1440 copolymer, we also can observe the ~1 nm SMA copolymer belt surrounding this SMALP for the first time, consistent with most models of SMA organization.
Collapse
Affiliation(s)
- Nathan G Brady
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA; The Second Target Station Project, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jon Nguyen
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Hugh M O'Neill
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Barry D Bruce
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA; Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Department of Microbiology, University of Tennessee, Knoxville, TN 37996, USA.
| |
Collapse
|
6
|
Golub M, Gätcke J, Subramanian S, Kölsch A, Darwish T, Howard JK, Feoktystov A, Matsarskaia O, Martel A, Porcar L, Zouni A, Pieper J. "Invisible" Detergents Enable a Reliable Determination of Solution Structures of Native Photosystems by Small-Angle Neutron Scattering. J Phys Chem B 2022; 126:2824-2833. [PMID: 35384657 DOI: 10.1021/acs.jpcb.2c01591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photosystems I (PSI) and II (PSII) are pigment-protein complexes capable of performing the light-induced charge separation necessary to convert solar energy into a biochemically storable form, an essential step in photosynthesis. Small-angle neutron scattering (SANS) is unique in providing structural information on PSI and PSII in solution under nearly physiological conditions without the need for crystallization or temperature decrease. We show that the reliability of the solution structure critically depends on proper contrast matching of the detergent belt surrounding the protein. Especially, specifically deuterated ("invisible") detergents are shown to be properly matched out in SANS experiments by a direct, quantitative comparison with conventional matching strategies. In contrast, protonated detergents necessarily exhibit incomplete matching so that related SANS results systematically overestimate the size of the membrane protein under study. While the solution structures obtained are close to corresponding high-resolution structures, we show that temperature and solution state lead to individual structural differences compared with high-resolution structures. We attribute these differences to the presence of a manifold of conformational substates accessible by protein dynamics under physiological conditions.
Collapse
Affiliation(s)
- M Golub
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| | - J Gätcke
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - S Subramanian
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - A Kölsch
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - T Darwish
- National Deuteration Facility, Australian Nuclear Science and Technology Organization, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - J K Howard
- National Deuteration Facility, Australian Nuclear Science and Technology Organization, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - A Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstr. 1, 85748 Garching, Germany
| | - O Matsarskaia
- Institut Laue-Langevin, 71 Avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - A Martel
- Institut Laue-Langevin, 71 Avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - L Porcar
- Institut Laue-Langevin, 71 Avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - A Zouni
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - J Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| |
Collapse
|
7
|
Golub M, Lokstein H, Soloviov D, Kuklin A, Wieland DCF, Pieper J. Light-Harvesting Complex II Adopts Different Quaternary Structures in Solution as Observed Using Small-Angle Scattering. J Phys Chem Lett 2022; 13:1258-1265. [PMID: 35089716 DOI: 10.1021/acs.jpclett.1c03614] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The high-resolution crystal structure of the trimeric major light-harvesting complex of photosystem II (LHCII) is often perceived as the basis for understanding its light-harvesting and photoprotective functions. However, the LHCII solution structure and its oligomerization or aggregation state may generally differ from the crystal structure and, moreover, also depend on its functional state. In this regard, small-angle scattering experiments provide the missing link by offering structural information in aqueous solution at physiological temperatures. Herein, we use small-angle scattering to investigate the solution structures of two different preparations of solubilized LHCII employing the nonionic detergents n-octyl-β-d-glucoside (OG) and n-dodecyl-β-D-maltoside (β-DM). The data reveal that the LHCII-OG complex is equivalent to the trimeric crystal structure. Remarkably, however, we observe─for the first time─a stable oligomer composed of three LHCII trimers in the case of the LHCII-β-DM preparation, implying additional pigment-pigment interactions. The latter complex is assumed to mimic trimer-trimer interactions which play an important role in the context of photoprotective nonphotochemical quenching.
Collapse
Affiliation(s)
- Maksym Golub
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| | - Heiko Lokstein
- Department of Chemical Physics and Optics, Charles University, Ke Karlovu 3, 121 16 Prague, Czech Republic
| | - Dmytro Soloviov
- Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna, Russia
- Moscow Institute of Physics and Technology, Institutskiy per. 9, 141701 Dolgoprudny, Russia
- Institute for Safety Problems of Nuclear Power Plants NAS of Ukraine, Lysogirska str. 12, 03028 Kyiv, Ukraine
| | - Alexander Kuklin
- Joint Institute for Nuclear Research, Joliot-Curie str. 6, 141980 Dubna, Russia
- Moscow Institute of Physics and Technology, Institutskiy per. 9, 141701 Dolgoprudny, Russia
| | - D C Florian Wieland
- Helmholtz Zentrum Geesthacht, Institute for Materials Research, Department for Metallic Biomaterials, 21502 Geesthacht, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| |
Collapse
|
8
|
Guo R, Sumner J, Qian S. Structure of Diisobutylene Maleic Acid Copolymer (DIBMA) and Its Lipid Particle as a “Stealth” Membrane-Mimetic for Membrane Protein Research. ACS APPLIED BIO MATERIALS 2021; 4:4760-4768. [DOI: 10.1021/acsabm.0c01626] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Rong Guo
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Grinnell College, Grinnell, Iowa 50112, United States
| | - Jacob Sumner
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Shuo Qian
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| |
Collapse
|
9
|
Insights into Solution Structures of Photosynthetic Protein Complexes from Small-Angle Scattering Methods. CRYSTALS 2021. [DOI: 10.3390/cryst11020203] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
High-resolution structures of photosynthetic pigment–protein complexes are often determined using crystallography or cryo-electron microscopy (cryo-EM), which are restricted to the use of protein crystals or to low temperatures, respectively. However, functional studies and biotechnological applications of photosystems necessitate the use of proteins isolated in aqueous solution, so that the relevance of high-resolution structures has to be independently verified. In this regard, small-angle neutron and X-ray scattering (SANS and SAXS, respectively) can serve as the missing link because of their capability to provide structural information for proteins in aqueous solution at physiological temperatures. In the present review, we discuss the principles and prototypical applications of SANS and SAXS using the photosynthetic pigment–protein complexes phycocyanin (PC) and Photosystem I (PSI) as model systems for a water-soluble and for a membrane protein, respectively. For example, the solution structure of PSI was studied using SAXS and SANS with contrast matching. A Guinier analysis reveals that PSI in solution is virtually free of aggregation and characterized by a radius of gyration of about 75 Å. The latter value is about 10% larger than expected from the crystal structure. This is corroborated by an ab initio structure reconstitution, which also shows a slight expansion of Photosystem I in buffer solution at room temperature. In part, this may be due to conformational states accessible by thermally activated protein dynamics in solution at physiological temperatures. The size of the detergent belt is derived by comparison with SANS measurements without detergent match, revealing a monolayer of detergent molecules under proper solubilization conditions.
Collapse
|
10
|
Abel S, Marchi M, Solier J, Finet S, Brillet K, Bonneté F. Structural insights into the membrane receptor ShuA in DDM micelles and in a model of gram-negative bacteria outer membrane as seen by SAXS and MD simulations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1863:183504. [PMID: 33157097 DOI: 10.1016/j.bbamem.2020.183504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 09/20/2020] [Accepted: 10/20/2020] [Indexed: 11/19/2022]
Abstract
Successful crystallization of membrane proteins in detergent micelles depends on key factors such as conformational stability of the protein in micellar assemblies, the protein-detergent complex (PDC) monodispersity and favorable protein crystal contacts by suitable shielding of the protein hydrophobic surface by the detergent belt. With the aim of studying the influence of amphiphilic environment on membrane protein structure, stability and crystallizability, we combine molecular dynamics (MD) simulations with SEC-MALLS and SEC-SAXS (Size Exclusion Chromatography in line with Multi Angle Laser Light Scattering or Small Angle X-ray Scattering) experiments to describe the protein-detergent interactions that could help to rationalize PDC crystallization. In this context, we compare the protein-detergent interactions of ShuA from Shigella dysenteriae in n-Dodecyl-β-D-Maltopyranoside (DDM) with ShuA inserted in a realistic model of gram-negative bacteria outer membrane (OM) containing a mixture of bacterial lipopolysaccharide and phospholipids. To evaluate the quality of the PDC models, we compute the corresponding SAXS curves from the MD trajectories and compare with the experimental ones. We show that computed SAXS curves obtained from the MD trajectories reproduce better the SAXS obtained from the SEC-SAXS experiments for ShuA surrounded by 268 DDM molecules. The MD results show that the DDM molecules form around ShuA a closed belt whose the hydrophobic thickness appears slightly smaller (~22 Å) than the hydrophobic transmembrane domain of the protein (24.6 Å) suggested by Orientations of Proteins in Membranes (OPM) database. The simulations also show that ShuA transmembrane domain is remarkably stable in all the systems except for the extracellular and periplasmic loops that exhibit larger movements due to specific molecular interactions with lipopolysaccharides (LPS). We finally point out that this detergent behavior may lead to the occlusion of the periplasmic hydrophilic surface and poor crystal contacts leading to difficulties in crystallization of ShuA in DDM.
Collapse
Affiliation(s)
- Stéphane Abel
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Massimo Marchi
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Justine Solier
- Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces, UMR 5279 CNRS Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, INP, F38000 Grenoble, France
| | - Stéphanie Finet
- Institut de Minéralogie, de Physique de Matériaux et de Cosmochimie, UMR 7590 CNRS-Sorbonne université, Bioinformatique et Biophysique, 4 Place Jussieu, F75005 Paris, France
| | - Karl Brillet
- Institut de Biologie Moléculaire et Cellulaire UPR 9002 CNRS, Architecture et Réactivité de l'ARN, 2 allée Konrad Roentgen, F67000 Strasbourg, France
| | - Françoise Bonneté
- Institut de Biologie Physico-Chimique (IBPC) UMR 7099 CNRS Université de Paris, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, 13 rue Pierre et Marie Curie, F75005 Paris, France.
| |
Collapse
|
11
|
Golub M, Hussein R, Ibrahim M, Hecht M, Wieland DCF, Martel A, Machado B, Zouni A, Pieper J. Solution Structure of the Detergent-Photosystem II Core Complex Investigated by Small-Angle Scattering Techniques. J Phys Chem B 2020; 124:8583-8592. [PMID: 32816484 DOI: 10.1021/acs.jpcb.0c07169] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Albeit achieving the X-ray diffraction structure of dimeric photosystem II core complexes (dPSIIcc) at the atomic resolution, the nature of the detergent belt surrounding dPSIIcc remains ambiguous. Therefore, the solution structure of the whole detergent-protein complex of dPSIIcc of Thermosynechococcus elongatus (T. elongatus) solubilized in n-dodecyl-ß-d-maltoside (ßDM) was investigated by a combination of small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) with contrast variation. First, the structure of dPSIIcc was studied separately in SANS experiments using a contrast of 5% D2O. Guinier analysis reveals that the dPSIIcc solution is virtually free of aggregation in the studied concentration range of 2-10 mg/mL dPSIIcc, and characterized by a radius of gyration of 62 Å. A structure reconstitution shows that dPSIIcc in buffer solution widely retains the crystal structure reported by X-ray free electron laser studies at room temperature with a slight expansion of the entire protein. Additional SANS experiments on dPSIIcc samples in a buffer solution containing 75% D2O provide information about the size and shape of the whole detergent-dPSIIcc. The maximum position of P(r) function increases to 68 Å, i.e., it is about 6 Å larger than that of dPSIIcc only, thus indicating the presence of an additional structure. Thus, it can be concluded that dPSIIcc is surrounded by a monomolecular belt of detergent molecules under appropriate solubilization conditions. The homogeneity of the ßDM-dPSIIcc solutions was also verified using dynamic light scattering. Complementary SAXS experiments indicate the presence of unbound detergent micelles by a separate peak consistent with a spherical shape possessing a radius of about 40 Å. The latter structure also contributes to the SANS data but rather broadens the SANS curve artificially. Without the simultaneous inspection of SANS and SAXS data, this effect may lead to an apparent underestimation of the size of the PS II-detergent complex. The formation of larger unbound detergent aggregates in solution prior to crystallization may have a significant effect on the crystal formation or quality of the ßDM-dPSIIcc.
Collapse
Affiliation(s)
- Maksym Golub
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| | - Rana Hussein
- Humboldt Universität zu Berlin, Philipp Str. 13, 10115 Berlin, Germany
| | - Mohamed Ibrahim
- Humboldt Universität zu Berlin, Philipp Str. 13, 10115 Berlin, Germany
| | - Max Hecht
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| | | | - Anne Martel
- Institut Laue-Langevin, 71 avenue des Martyrs, 38043 Grenoble, France
| | - Barbara Machado
- European Synchrotron Radiation Facility, 71 avenue des Martyrs, 38043 Grenoble, France
| | - Athina Zouni
- Humboldt Universität zu Berlin, Philipp Str. 13, 10115 Berlin, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| |
Collapse
|
12
|
Clark ST, Arras MML, Sarles SA, Frymier PD. Lipid shape determination of detergent solubilization in mixed-lipid liposomes. Colloids Surf B Biointerfaces 2019; 187:110609. [PMID: 31806354 DOI: 10.1016/j.colsurfb.2019.110609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/17/2019] [Accepted: 10/21/2019] [Indexed: 11/16/2022]
Abstract
The effects of lipid charge and head group size on liposome partitioning by detergents is an important consideration for applications such as liposomal drug delivery or proteoliposome formation. Yet, the solubilization of mixed-lipid liposomes, those containing multiple types of lipids, by detergents has received insufficient attention. This study examines the incorporation into and subsequent dissolution of mixed-lipid liposomes comprised of both egg phosphatidylcholine (ePC) and egg phosphatidic acid (ePA) by the detergent Triton-X100 (TX). Liposomes were prepared with mixtures of the two lipids, ePC and ePA, at molar ratios from 0 to 1, then step-wise solubilized with TX. Changes in turbidity, size distribution, and molar heat power at constant temperature throughout the solubilization process were assessed. The data suggest that the difference in lipid shapes (shape factors = 0.74 and 1.4 [1,2]) affects packing in membranes, and hence influences how much TX can be incorporated before disruption. As such, liposomes containing the observed ratios of ePA incorporated higher concentrations of TX before initiating dissolution into detergent and lipid mixed-micelles. The cause was concluded to be increased mismatching in the bilayer from the conical shape of ePA compared to the cylindrical shape of ePC. Additionally, the degree to which ePA is approximated as conical versus cylindrical was modulated with pH. It was confirmed that less conical ePA behaved more similarly to ePC than more conical ePA. The understanding gained here on lipid shape in liposome incorporation of TX enables research to use in vitro liposomes that more closely mimic native membranes.
Collapse
Affiliation(s)
- Samantha T Clark
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN 37996, USA
| | - Matthias M L Arras
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Stephen A Sarles
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, 1512 Middle Drive, 414 Dougherty Engineering Building, Knoxville, TN 37996, USA
| | - Paul D Frymier
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, 1512 Middle Dr, Knoxville, TN 37996, USA.
| |
Collapse
|
13
|
Yu D, Lan J, Khan NU, Li Q, Xu F, Huang G, Xu H, Huang F. The in vitro synergistic denaturation effect of heat and surfactant on photosystem I isolated from Arthrospira Platensis. PHOTOSYNTHESIS RESEARCH 2019; 141:229-243. [PMID: 30725234 DOI: 10.1007/s11120-019-00623-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 01/26/2019] [Indexed: 06/09/2023]
Abstract
Photosystem I (PSI) generates the most negative redox potential found in nature, and the performance of solar energy conversion into alternative energy sources in artificial systems highly depends on the thermal stability of PSI. Thus, understanding thermal denaturation is an important prerequisite for the use of PSI at elevated temperatures. To assess the thermal stability of surfactant-solubilized PSI from cyanobacteria Arthrospira Platensis, the synergistic denaturation effect of heat and surfactant was studied. At room temperature, surfactant n-dodecyl-β-D-maltoside solubilized PSI trimer gradually disassembles into PSI monomers and free pigments over long time. In the solubilizing process of PSI particles, surfactant can uncouple pigments of PSI, and the high concentration of surfactant causes the pigment to uncouple more; after the surfactant-solubilizing process, the uncoupling is relatively slow. During the heating process, changes were monitored by transmittance T800nm, ellipticity θ686nm and θ222nm, upon slow heating (1.5 °C per minute) of samples in Tris buffer (20 mM, pH 7.8) from 20 to 95 °C. The thermal denaturation of surfactant-solubilized PSI is a much more complicated process, which includes the uncoupling of pigments by surfactants, the disappearance of surrounding surfactants, and the unfolding of PSI α-helices. During the heating process, the uncoupling chlorophyll a (Chla) and converted pheophytin (Pheo) can form excitons of Chla-Pheo. The secondary structure α-helix of PSI proteins is stable up to 87-92 °C in the low-concentration surfactant solubilized PSI, and high-concentration surfactant and pigments uncoupling can accelerate the α-helical unfolding.
Collapse
Affiliation(s)
- Daoyong Yu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, Shandong, China.
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China.
| | - Jinxiao Lan
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Naseer Ullah Khan
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Quan Li
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Fengxi Xu
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Guihong Huang
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China
| | - Hai Xu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, Shandong, China.
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China.
| | - Fang Huang
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum (East China), Qingdao, 266580, Shandong, China.
- Center for Bioengineering and Biotechnology, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, Shandong, China.
| |
Collapse
|
14
|
Brady NG, Li M, Ma Y, Gumbart JC, Bruce BD. Non-detergent isolation of a cyanobacterial photosystem I using styrene maleic acid alternating copolymers. RSC Adv 2019; 9:31781-31796. [PMID: 35527920 PMCID: PMC9072662 DOI: 10.1039/c9ra04619d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 10/02/2019] [Indexed: 11/21/2022] Open
Abstract
Trimeric Photosystem I (PSI) from the thermophilic cyanobacteriumThermosynechococcus elongatus(Te) is the largest membrane protein complex to be encapsulated within a SMALP to date.
Collapse
Affiliation(s)
- Nathan G. Brady
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
| | - Meng Li
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
- Bredesen Center for Interdisciplinary Research and Education
| | - Yue Ma
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
| | | | - Barry D. Bruce
- Department of Biochemistry & Cellular and Molecular Biology
- University of Tennessee at Knoxville
- Knoxville
- USA
- Bredesen Center for Interdisciplinary Research and Education
| |
Collapse
|
15
|
García-Negrón V, Oyedele AD, Ponce E, Rios O, Harper DP, Keffer DJ. Evaluation of nano- and mesoscale structural features in composite materials through hierarchical decomposition of the radial distribution function. J Appl Crystallogr 2018. [DOI: 10.1107/s1600576717016843] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Composite materials possessing both crystalline and amorphous domains, when subjected to X-ray and neutron scattering, generate diffraction patterns that are often difficult to interpret. One approach is to perform atomistic simulations of a proposed structure, from which the analogous diffraction pattern can be obtained for validation. The structure can be iteratively refined until simulation and experiment agree. The practical drawback to this approach is the significant computational resources required for the simulations. In this work, an alternative approach based on a hierarchical decomposition of the radial distribution function is used to generate a physics-based model allowing rapid interpretation of scattering data. In order to demonstrate the breadth of this approach, it is applied to a series of carbon composites. The model is compared with atomistic simulation results in order to demonstrate that the contributions of the crystalline and amorphous domains, as well as their interfaces, are correctly captured. Because the model is more efficient, additional structural refinement is performed to increase the agreement of the simulation result with the experimental data. The model achieves a reduction in computational effort of six orders of magnitude relative to simulation. The model can be generally extended to other composite materials.
Collapse
|
16
|
Midtgaard SR, Darwish TA, Pedersen MC, Huda P, Larsen AH, Jensen GV, Kynde SAR, Skar‐Gislinge N, Nielsen AJZ, Olesen C, Blaise M, Dorosz JJ, Thorsen TS, Venskutonytė R, Krintel C, Møller JV, Frielinghaus H, Gilbert EP, Martel A, Kastrup JS, Jensen PE, Nissen P, Arleth L. Invisible detergents for structure determination of membrane proteins by small‐angle neutron scattering. FEBS J 2017; 285:357-371. [DOI: 10.1111/febs.14345] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/20/2017] [Accepted: 11/21/2017] [Indexed: 12/23/2022]
Affiliation(s)
- Søren Roi Midtgaard
- Structural Biophysics X‐ray and Neutron Science The Niels Bohr Institute University of Copenhagen Denmark
| | - Tamim A. Darwish
- National Deuteration Facility Australian Nuclear Science and Technology Organization Lucas Heights Australia
| | - Martin Cramer Pedersen
- Structural Biophysics X‐ray and Neutron Science The Niels Bohr Institute University of Copenhagen Denmark
- Department of Applied Mathematics Research School of Physics and Engineering Australian National University Canberra Australia
| | - Pie Huda
- Structural Biophysics X‐ray and Neutron Science The Niels Bohr Institute University of Copenhagen Denmark
| | - Andreas Haahr Larsen
- Structural Biophysics X‐ray and Neutron Science The Niels Bohr Institute University of Copenhagen Denmark
| | - Grethe Vestergaard Jensen
- Structural Biophysics X‐ray and Neutron Science The Niels Bohr Institute University of Copenhagen Denmark
| | | | - Nicholas Skar‐Gislinge
- Structural Biophysics X‐ray and Neutron Science The Niels Bohr Institute University of Copenhagen Denmark
| | | | - Claus Olesen
- Department of Biomedicine Aarhus University Denmark
| | - Mickael Blaise
- Institut de Recherche en Infectiologie de Montpellier CNRS Université de Montpellier France
- Centre for Carbohydrate Recognition and Signaling Department of Molecular Biology Aarhus University Denmark
| | - Jerzy Józef Dorosz
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Denmark
| | - Thor Seneca Thorsen
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Denmark
| | - Raminta Venskutonytė
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Denmark
| | - Christian Krintel
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Denmark
| | - Jesper V. Møller
- Department of Biomedicine Aarhus University Denmark
- Department of Molecular Biology and Genetics Centre for Membrane Pumps in Cells and Disease – PUMPkin Danish National Research Foundation Aarhus University Denmark
| | | | - Elliot Paul Gilbert
- Australian Centre for Neutron Scattering Australian Nuclear Science and Technology Organization Lucas Heights Australia
| | | | - Jette Sandholm Kastrup
- Department of Drug Design and Pharmacology Faculty of Health and Medical Sciences University of Copenhagen Denmark
| | - Poul Erik Jensen
- Copenhagen Plant Science Center University of Copenhagen Denmark
| | - Poul Nissen
- Department of Molecular Biology and Genetics Centre for Membrane Pumps in Cells and Disease – PUMPkin Danish National Research Foundation Aarhus University Denmark
- DANDRITE Nordic‐EMBL Partnership for Molecular Medicine Aarhus University Denmark
| | - Lise Arleth
- Structural Biophysics X‐ray and Neutron Science The Niels Bohr Institute University of Copenhagen Denmark
| |
Collapse
|
17
|
Golub M, Hejazi M, Kölsch A, Lokstein H, Wieland DCF, Zouni A, Pieper J. Solution structure of monomeric and trimeric photosystem I of Thermosynechococcus elongatus investigated by small-angle X-ray scattering. PHOTOSYNTHESIS RESEARCH 2017; 133:163-173. [PMID: 28258466 DOI: 10.1007/s11120-017-0342-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/23/2017] [Indexed: 06/06/2023]
Abstract
The structure of monomeric and trimeric photosystem I (PS I) of Thermosynechococcus elongatus BP1 (T. elongatus) was investigated by small-angle X-ray scattering (SAXS). The scattering data reveal that the protein-detergent complexes possess radii of gyration of 58 and 78 Å in the cases of monomeric and trimeric PS I, respectively. The results also show that the samples are monodisperse, virtually free of aggregation, and contain empty detergent micelles. The shape of the protein-detergent complexes can be well approximated by elliptical cylinders with a height of 78 Å. Monomeric PS I in buffer solution exhibits minor and major radii of the elliptical cylinder of about 50 and 85 Å, respectively. In the case of trimeric PS I, both radii are equal to about 110 Å. The latter model can be shown to accommodate three elliptical cylinders equal to those describing monomeric PS I. A structure reconstitution also reveals that the protein-detergent complexes are larger than their respective crystal structures. The reconstituted structures are larger by about 20 Å mainly in the region of the hydrophobic surfaces of the monomeric and trimeric PS I complexes. This seeming contradiction can be resolved by the addition of a detergent belt constituted by a monolayer of dodecyl-β-D-maltoside molecules. Assuming a closest possible packing, a number of roughly 1024 and 1472 detergent molecules can be determined for monomeric and trimeric PS I, respectively. Taking the monolayer of detergent molecules into account, the solution structure can be almost perfectly modeled by the crystal structures of monomeric and trimeric PS I.
Collapse
Affiliation(s)
- Maksym Golub
- Institute of Physics, University of Tartu, Wilhelm Ostwaldi 1, 50411, Tartu, Estonia
| | - Mahdi Hejazi
- Humboldt Universität zu Berlin, Philipp Str. 13, 10115, Berlin, Germany
| | - Adrian Kölsch
- Humboldt Universität zu Berlin, Philipp Str. 13, 10115, Berlin, Germany
| | - Heiko Lokstein
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16, Prague, Czech Republic
| | - D C Florian Wieland
- Department for Metalic Biomaterials, Institute for Materials Research, Helmholtz Zentrum Geesthacht, 21502, Geesthacht, Germany
| | - Athina Zouni
- Humboldt Universität zu Berlin, Philipp Str. 13, 10115, Berlin, Germany
| | - Jörg Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwaldi 1, 50411, Tartu, Estonia.
| |
Collapse
|
18
|
Garrido PF, Brocos P, Amigo A, García-Río L, Gracia-Fadrique J, Piñeiro Á. STAND: Surface Tension for Aggregation Number Determination. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:3917-3925. [PMID: 27048988 DOI: 10.1021/acs.langmuir.6b00477] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Taking advantage of the extremely high dependence of surface tension on the concentration of amphiphilic molecules in aqueous solution, a new model based on the double equilibrium between free and aggregated molecules in the liquid phase and between free molecules in the liquid phase and those adsorbed at the air/liquid interface is presented and validated using literature data and fluorescence measurements. A key point of the model is the use of both the Langmuir isotherm and the Gibbs adsorption equation in terms of free molecules instead of the nominal concentration of the solute. The application of the model should be limited to non ionic compounds since it does not consider the presence of counterions. It requires several coupled nonlinear fittings for which we developed a software that is publicly available in our server as a web application. Using this tool, it is straightforward to get the average aggregation number of an amphiphile, the micellization free energy, the adsorption constant, the maximum surface excess (and so the minimum area per molecule), the distribution of solute in the liquid phase between free and aggregate species, and the surface coverage in only a couple of seconds, just by uploading a text file with surface tension vs concentration data and the corresponding uncertainties.
Collapse
Affiliation(s)
- Pablo F Garrido
- Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain
| | - Pilar Brocos
- Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain
| | - Alfredo Amigo
- Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain
| | - Luis García-Río
- Departamento de Química Física, Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), Facultade de Química, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain
| | - Jesús Gracia-Fadrique
- Departamento de Fisicoquímica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria , 04510 México D.F., Mexico
| | - Ángel Piñeiro
- Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela , 15782 Santiago de Compostela, Spain
| |
Collapse
|
19
|
Harris BJ, Cheng X, Frymier P. Structure and Function of Photosystem I–[FeFe] Hydrogenase Protein Fusions: An All-Atom Molecular Dynamics Study. J Phys Chem B 2016; 120:599-609. [DOI: 10.1021/acs.jpcb.5b07812] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bradley J. Harris
- College
of Engineering and Computer Science, University of Tennessee, Chattanooga, Tennessee 37403, United States
| | - Xiaolin Cheng
- Center for
Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | | |
Collapse
|
20
|
Heberle FA, Myles DAA, Katsaras J. Biomembranes research using thermal and cold neutrons. Chem Phys Lipids 2015; 192:41-50. [PMID: 26241882 DOI: 10.1016/j.chemphyslip.2015.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/25/2015] [Accepted: 07/27/2015] [Indexed: 01/26/2023]
Abstract
In 1932 James Chadwick discovered the neutron using a polonium source and a beryllium target (Chadwick, 1932). In a letter to Niels Bohr dated February 24, 1932, Chadwick wrote: "whatever the radiation from Be may be, it has most remarkable properties." Where it concerns hydrogen-rich biological materials, the "most remarkable" property is the neutron's differential sensitivity for hydrogen and its isotope deuterium. Such differential sensitivity is unique to neutron scattering, which unlike X-ray scattering, arises from nuclear forces. Consequently, the coherent neutron scattering length can experience a dramatic change in magnitude and phase as a result of resonance scattering, imparting sensitivity to both light and heavy atoms, and in favorable cases to their isotopic variants. This article describes recent biomembranes research using a variety of neutron scattering techniques.
Collapse
Affiliation(s)
- F A Heberle
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States; Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States
| | - D A A Myles
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States
| | - J Katsaras
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States; Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, United States.
| |
Collapse
|
21
|
|