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Peddinti V, Rout B, Agnihotri TG, Gomte SS, Jain A. Functionalized liposomes: an enticing nanocarrier for management of glioma. J Liposome Res 2024; 34:349-367. [PMID: 37855432 DOI: 10.1080/08982104.2023.2270060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 10/07/2023] [Indexed: 10/20/2023]
Abstract
Glioma is one of the most severe central nervous systems (CNS)-specific tumors, with rapidly growing malignant glial cells accounting for roughly half of all brain tumors and having a poor survival rate ranging from 12 to 15 months. Despite being the most often used technique for glioma therapy, conventional chemotherapy suffers from low permeability of the blood-brain barrier (BBB) and blood-brain tumor barrier (BBTB) to anticancer drugs. When it comes to nanocarriers, liposomes are thought of as one of the most promising nanocarrier systems for glioma treatment. However, owing to BBB tight junctions, non-targeted liposomes, which passively accumulate in most cancer cells primarily via the increased permeability and retention effect (EPR), would not be suitable for glioma treatment. The surface modification of liposomes with various active targeting ligands has shown encouraging outcomes in the recent times by allowing various chemotherapy drugs to pass across the BBB and BBTB and enter glioma cells. This review article introduces by briefly outlining the landscape of glioma, its classification, and some of the pathogenic causes. Further, it discusses major barriers for delivering drugs to glioma such as the BBB, BBTB, and tumor microenvironment. It further discusses modified liposomes such as long-acting circulating liposomes, actively targeted liposomes, stimuli responsive liposomes. Finally, it highlighted the limitations of liposomes in the treatment of glioma and the various actively targeted liposomes undergoing clinical trials for the treatment of glioma.
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Affiliation(s)
- Vasu Peddinti
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat, India
| | - Biswajit Rout
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat, India
| | - Tejas Girish Agnihotri
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat, India
| | - Shyam Sudhakar Gomte
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat, India
| | - Aakanchha Jain
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, Gujarat, India
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2
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Ahmaruzzaman M, Roy P, Bonilla-Petriciolet A, Badawi M, Ganachari SV, Shetti NP, Aminabhavi TM. Polymeric hydrogels-based materials for wastewater treatment. CHEMOSPHERE 2023; 331:138743. [PMID: 37105310 DOI: 10.1016/j.chemosphere.2023.138743] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 05/19/2023]
Abstract
Low-cost and reliable wastewater treatment is a relevant issue worldwide to reduce the concentration of environmental pollutants. Industrial effluents containing dyes, heavy metals, and other inorganic and organic compounds can pollute water resources; therefore, novel technologies are required to mitigate and control their release into the environment. Adsorption is one of the simplest methods for treating contaminated water in which a wide spectrum of adsorbents can be used to remove emerging compounds. Hydrogels are interesting materials with high adsorption capacities that can be synthesized via green routes. These adsorbents are promising for large-scale industrial wastewater treatment applications; however, gaps still exist in achieving sustainable commercial implementation. This review focuses on the discussion and analysis of preparation, characterization, and adsorption properties of hydrogels for water purification. The advantages of these polymeric materials for water treatment were analyzed, including their performance in the removal of different organic and inorganic contaminants. Recent advances in the functionalization of hydrogels and the synthesis of novel composites have also been described. The adsorption capacities of hydrogel-based adsorbents are higher than 500 mg/g for different organic and inorganic pollutants, and can reach values of up to >2000 mg/g for organic compounds, significantly outperforming other materials reported for water cleaning. The main interactions involved in the adsorption of water pollutants using hydrogel-based adsorbents were described and explained to allow the interpretation of their removal mechanisms. The current challenges in the implementation of hydrogels for water purification in real-life operations are also highlighted. This review provides an updated picture of hydrogels as interesting materials to address water depollution worldwide.
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Affiliation(s)
- Md Ahmaruzzaman
- Department of Chemistry, National Institute of Technology Silchar, 788010, Assam, India.
| | - Prerona Roy
- Department of Chemistry, National Institute of Technology Silchar, 788010, Assam, India
| | | | - Michael Badawi
- Laboratoire de Physique et Chimie Théoriques UMR CNRS 7019, Université de Lorraine, Nancy, France
| | - Sharanabasava V Ganachari
- Center for Energy and Environment, School of Advanced Sciences, KLE Technological University, Hubballi, 580 031, India
| | - Nagaraj P Shetti
- Center for Energy and Environment, School of Advanced Sciences, KLE Technological University, Hubballi, 580 031, India
| | - Tejraj M Aminabhavi
- Center for Energy and Environment, School of Advanced Sciences, KLE Technological University, Hubballi, 580 031, India.
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Cheng H, Zheng L, Liu N, Huang C, Xu J, Lu Y, Cui X, Xu K, Hou Y, Tang J, Zhang Z, Li J, Ni X, Chen Y, Peng H, Wang HW. Dual-Affinity Graphene Sheets for High-Resolution Cryo-Electron Microscopy. J Am Chem Soc 2023; 145:8073-8081. [PMID: 37011903 PMCID: PMC10103130 DOI: 10.1021/jacs.3c00659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Abstract
With the development of cryo-electron microscopy (cryo-EM), high-resolution structures of macromolecules can be reconstructed by the single particle method efficiently. However, challenges may still persist during the specimen preparation stage. Specifically, proteins tend to adsorb at the air-water interface and exhibit a preferred orientation in vitreous ice. To overcome these challenges, we have explored dual-affinity graphene (DAG) modified with two different affinity ligands as a supporting material for cryo-EM sample preparation. The ligands can bind to distinct sites on the corresponding tagged particles, which in turn generates various orientation distributions of particles and prevents the adsorption of protein particles onto the air-water interface. As expected, the DAG exhibited high binding specificity and affinity to target macromolecules, resulting in more balanced particle Euler angular distributions compared to single functionalized graphene on two different protein cases, including the SARS -CoV-2 spike glycoprotein. We anticipate that the DAG grids will enable facile and efficient three-dimensional (3D) reconstruction for cryo-EM structural determination, providing a robust and general technique for future studies.
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Affiliation(s)
- Hang Cheng
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Joint Graduate Program of Peking-Tsinghua-NIBS, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Shuimu BioSciences Ltd., Beijing 102206, China
| | - Liming Zheng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua University, Beijing 100084, China
| | - Congyuan Huang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jie Xu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ye Lu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaoya Cui
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua University, Beijing 100084, China
| | - Kui Xu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuan Hou
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Junchuan Tang
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Zhong Zhang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Jing Li
- Shuimu BioSciences Ltd., Beijing 102206, China
| | - Xiaodan Ni
- Shuimu BioSciences Ltd., Beijing 102206, China
| | - Yanan Chen
- School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Hailin Peng
- Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- Beijing Graphene Institute (BGI), Beijing 100095, China
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
- Joint Graduate Program of Peking-Tsinghua-NIBS, School of Life Sciences, Tsinghua University, Beijing 100084, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua University, Beijing 100084, China
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Balser S, Zhao Z, Zharnikov M, Terfort A. Effect of the crosslinking agent on the biorepulsive and mechanical properties of polyglycerol membranes. Colloids Surf B Biointerfaces 2023; 225:113271. [PMID: 36996629 DOI: 10.1016/j.colsurfb.2023.113271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 02/28/2023] [Accepted: 03/16/2023] [Indexed: 04/01/2023]
Abstract
Polyglycerol (PG) based surfaces materials and surfaces are well-established bio-compatible materials. Crosslinking of the dendrimeric molecules via their OH groups improves their mechanical stability up to the point that free-standing materials can be attained. Here, we investigate the effect of different crosslinkers on PG films regarding their biorepulsivity and mechanical properties. For this purpose, PG films with different thicknesses (15, 50 and 100 nm) were prepared by polymerizing glycidol in a ring-opening polymerization onto hydroxyl-terminated Si substrates. These films were then crosslinked using ethylene glycol diglycidyl ether (EGDGE), divinyl sulfone (DVS), glutaraldehyde (GA), 1,11-di(mesyloxy)-3,6,9-trioxaundecane (TEG-Ms2) or 1,11-dibromo-3,6,9-trioxaundecane (TEG-Br2), respectively. While DVS, TEG-Ms2, and TEG-Br2 resulted in slightly thinned films, presumably due to loss of unbound material, increase of film thickness was observed with GA and, in particular, EDGDE, what can be explained by the different crosslinking mechanisms. The biorepulsive properties of the crosslinked PG films were characterized by water contact angle (WCA) goniometry and various adsorption assays involving proteins (serum albumine, fibrinogen, γ-globulin) and bacteria (E. coli), showing that some crosslinkers (EGDGE, DVS) improved the biorepulsive properties, while others deteriorated them (TEG-Ms2, TEG-Br2, GA). As the crosslinking stabilized the films, it was possible to use a lift-off procedure to obtain free-standing membranes if the thickness of the films was 50 nm or larger. Their mechanical properties were examined with a bulge test showing high elasticities, with the Young's moduli increasing in the order GA ≈ EDGDE < TEG-Br2 ≈ TEG-Ms2 < DVS.
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Affiliation(s)
- Sebastian Balser
- Goethe University Frankfurt, Department of Chemistry, Institute of Inorganic and Analytical Chemistry, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Zhiyong Zhao
- Heidelberg University, Department of Applied Physical Chemistry, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Michael Zharnikov
- Heidelberg University, Department of Applied Physical Chemistry, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany.
| | - Andreas Terfort
- Goethe University Frankfurt, Department of Chemistry, Institute of Inorganic and Analytical Chemistry, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany.
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Elastic Properties of Poly(ethylene glycol) Nanomembranes and Respective Implications. MEMBRANES 2022; 12:membranes12050509. [PMID: 35629834 PMCID: PMC9143594 DOI: 10.3390/membranes12050509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/03/2022] [Accepted: 05/05/2022] [Indexed: 12/04/2022]
Abstract
Free-standing poly(ethylene glycol) (PEG) membranes were prepared from amine- and epoxy-terminated four-arm STAR-PEG precursors in a thickness range of 40–320 nm. The membranes feature high stability and an extreme elasticity, as emphasized by the very low values of Young’s modulus, varying from 2.08 MPa to 2.6 MPa over the studied thickness range. The extreme elasticity of the membranes stems from the elastomer-like character of the PEG network, consisting of the STAR-PEG cores interconnected by crosslinked PEG chains. This elasticity is only slightly affected by a moderate reduction in the interconnections at a deviation from the standard 1:1 composition of the precursors. However, both the elasticity and stability of the membranes are strongly deteriorated by a strong distortion of the network imposed by electron irradiation of the membranes. In contrast, exposure of the membranes to ultraviolet (UV) light (254 nm) does not affect their elastic properties, supporting the assumption that the only effect of such treatment is the decomposition of the PEG material with subsequent desorption of the released fragments. An analysis of the data allowed for the exclusion of so called “hot electrons” as a possible mechanism behind the modification of the PEG membranes by UV light.
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Scherr J, Tang Z, Küllmer M, Balser S, Scholz AS, Winter A, Parey K, Rittner A, Grininger M, Zickermann V, Rhinow D, Terfort A, Turchanin A. Smart Molecular Nanosheets for Advanced Preparation of Biological Samples in Electron Cryo-Microscopy. ACS NANO 2020; 14:9972-9978. [PMID: 32589396 DOI: 10.1021/acsnano.0c03052] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transmission electron cryo-microscopy (cryoEM) of vitrified biological specimens is a powerful tool for structural biology. Current preparation of vitrified biological samples starts off with sample isolation and purification, followed by the fixation in a freestanding layer of amorphous ice. Here, we demonstrate that ultrathin (∼10 nm) smart molecular nanosheets having specific biorecognition sites embedded in a biorepulsive layer covalently bound to a mechanically stable carbon nanomembrane allow for a much simpler isolation and structural analysis. We characterize in detail the engineering of these nanosheets and their biorecognition properties employing complementary methods such as X-ray photoelectron and infrared spectroscopy, atomic force microscopy as well as surface plasmon resonance measurements. The desired functionality of the developed nanosheets is demonstrated by in situ selection of a His-tagged protein from a mixture and its subsequent structural analysis by cryoEM.
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Affiliation(s)
- Julian Scherr
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Zian Tang
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
| | - Maria Küllmer
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
| | - Sebastian Balser
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Alexander Stefan Scholz
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Andreas Winter
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
| | - Kristian Parey
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt, Germany
| | - Alexander Rittner
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt, Germany
| | - Martin Grininger
- Institute of Organic Chemistry and Chemical Biology, Buchmann Institute for Molecular Life Sciences, University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt, Germany
| | - Volker Zickermann
- Institute of Biochemistry II, Medical School, University of Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Daniel Rhinow
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt, Germany
| | - Andreas Terfort
- Department of Chemistry, University of Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Andrey Turchanin
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany
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Raghuwanshi VS, Garnier G. Characterisation of hydrogels: Linking the nano to the microscale. Adv Colloid Interface Sci 2019; 274:102044. [PMID: 31677493 DOI: 10.1016/j.cis.2019.102044] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 09/26/2019] [Accepted: 10/01/2019] [Indexed: 02/07/2023]
Abstract
Hydrogels are water enriched soft materials widely used for applications as varied as super absorbents, breast implants and contact lenses. Hydrogels have also been designed for smart functional devices including drug delivery, tissue engineering and diagnostics such as blood typing. The hydrogel properties and functionality depend on their crosslinking density, water holding capacity and fibre/polymer composition, strength and internal structure. Determining these parameters and properties are challenging. This review presents the main characterisation methods providing both qualitative and quantitative information of the structures and compositions of hydrogel. The length scale of interest ranges from the nano to the micro scale and the techniques and results are analysed in relationship to the hydrogel macroscopic applications. The characterisation methods examined aim at quantifying swelling, mechanical strength, mesh size, bound and free water content, pore structure, chemical composition, strength of chemical bonds and mechanical strength. These hydrogel parameters enable us to understand the fundamental mechanisms of hydrogel formation, to control their structure and functionality, and to optimize and tailor specific hydrogel properties to engineer particular applications.
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Scherr J, Neuhaus A, Parey K, Klusch N, Murphy BJ, Zickermann V, Kühlbrandt W, Terfort A, Rhinow D. Noncovalent Functionalization of Carbon Substrates with Hydrogels Improves Structural Analysis of Vitrified Proteins by Electron Cryo-Microscopy. ACS NANO 2019; 13:7185-7190. [PMID: 31117383 DOI: 10.1021/acsnano.9b02651] [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] [Indexed: 06/09/2023]
Abstract
In electron cryo-microscopy, structure determination of protein molecules is frequently hampered by adsorption of the particles to the support film material, typically amorphous carbon. Here, we report that pyrene derivatives with one or two polyglycerol (PG) side chains bind to the amorphous carbon films, forming a biorepulsive hydrogel layer so that the number of protein particles in the vitreous ice drastically increases. This approach could be extended by adding a hydrogel-functionalized carbon nanotube network (HyCaNet, the hydrogel again being formed from the PG-pyrene derivatives), which stabilized the protein-containing thin ice films during imaging with the electron beam. The stabilization resulted in reduced particle motion by up to 70%. These substrates were instrumental for determining the structure of a large membrane protein complex.
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Affiliation(s)
- Julian Scherr
- Department of Chemistry, Institute of Inorganic and Analytical Chemistry , Goethe-University Frankfurt , Max-von-Laue-Str. 7 , 60438 Frankfurt , Germany
| | - Alexander Neuhaus
- Department of Structural Biology , Max Planck Institute of Biophysics , Max-von-Laue-Str. 3 , 60438 Frankfurt , Germany
| | - Kristian Parey
- Department of Structural Biology , Max Planck Institute of Biophysics , Max-von-Laue-Str. 3 , 60438 Frankfurt , Germany
| | - Niklas Klusch
- Department of Structural Biology , Max Planck Institute of Biophysics , Max-von-Laue-Str. 3 , 60438 Frankfurt , Germany
| | - Bonnie J Murphy
- Department of Structural Biology , Max Planck Institute of Biophysics , Max-von-Laue-Str. 3 , 60438 Frankfurt , Germany
| | - Volker Zickermann
- Structural Bioenergetics Group , Institute of Biochemistry II, Medical School , Max-von-Laue-Str. 9 , 60438 Frankfurt , Germany
| | - Werner Kühlbrandt
- Department of Structural Biology , Max Planck Institute of Biophysics , Max-von-Laue-Str. 3 , 60438 Frankfurt , Germany
| | - Andreas Terfort
- Department of Chemistry, Institute of Inorganic and Analytical Chemistry , Goethe-University Frankfurt , Max-von-Laue-Str. 7 , 60438 Frankfurt , Germany
| | - Daniel Rhinow
- Department of Structural Biology , Max Planck Institute of Biophysics , Max-von-Laue-Str. 3 , 60438 Frankfurt , Germany
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Klusch N, Murphy BJ, Mills DJ, Yildiz Ö, Kühlbrandt W. Structural basis of proton translocation and force generation in mitochondrial ATP synthase. eLife 2017; 6:33274. [PMID: 29210357 PMCID: PMC5747523 DOI: 10.7554/elife.33274] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/05/2017] [Indexed: 01/15/2023] Open
Abstract
ATP synthases produce ATP by rotary catalysis, powered by the electrochemical proton gradient across the membrane. Understanding this fundamental process requires an atomic model of the proton pathway. We determined the structure of an intact mitochondrial ATP synthase dimer by electron cryo-microscopy at near-atomic resolution. Charged and polar residues of the a-subunit stator define two aqueous channels, each spanning one half of the membrane. Passing through a conserved membrane-intrinsic helix hairpin, the lumenal channel protonates an acidic glutamate in the c-ring rotor. Upon ring rotation, the protonated glutamate encounters the matrix channel and deprotonates. An arginine between the two channels prevents proton leakage. The steep potential gradient over the sub-nm inter-channel distance exerts a force on the deprotonated glutamate, resulting in net directional rotation.
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Affiliation(s)
- Niklas Klusch
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Bonnie J Murphy
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Deryck J Mills
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Özkan Yildiz
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
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