1
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Han D, Xu J, Zhou P. Optimization of Chinese film and television communication technology in Portuguese-speaking areas under the application of digital Internet of Things. Heliyon 2024; 10:e37572. [PMID: 39309914 PMCID: PMC11416528 DOI: 10.1016/j.heliyon.2024.e37572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 09/05/2024] [Accepted: 09/05/2024] [Indexed: 09/25/2024] Open
Abstract
With the continuous change and progress of the world system, cultural communication has become a vital topic in today's society. This study aims to optimize the communication effect of Chinese film in Portuguese-speaking countries and promote the development of cultural communication in China through deep learning (DL) technology. First, this study utilizes DL technology to design film feature recognition and classification models to provide technical support for Chinese film communication. Second, by exploring the principle, development, and function of the digital Internet of Things, the study analyzes the evolution and spread of Chinese film in Portuguese-speaking countries and uses the Bayes algorithm to optimize the model. The results show that the calculation time of the designed model is shorter and the accuracy is higher, which offers an important reference for the effective communication of Chinese films in Portuguese-speaking countries. Hence, this study not only provides technical support for the improvement of the international communication effect of Chinese film but also contributes to the development of cultural communication in China.
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Affiliation(s)
- Dong Han
- College of Literature and Journalism, Sanjiang University, Nanjing, 210012, Jiangsu, China
- Visiting Scholar, One Belt one Road Research Center of Macau, City University of Macau, Macau, China
| | - Jie Xu
- Institute of Portuguese-speaking Countries, City University of Macau, Macau, China
| | - Ping Zhou
- One Belt one Road Research Center of Macau, City University of Macau, Macau, China
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2
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Zheng L, Xu J, Wang W, Gao X, Zhao C, Guo W, Sun L, Cheng H, Meng F, Chen B, Sun W, Jia X, Zhou X, Wu K, Liu Z, Ding F, Liu N, Wang HW, Peng H. Self-assembled superstructure alleviates air-water interface effect in cryo-EM. Nat Commun 2024; 15:7300. [PMID: 39181869 PMCID: PMC11344764 DOI: 10.1038/s41467-024-51696-w] [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: 01/30/2024] [Accepted: 08/15/2024] [Indexed: 08/27/2024] Open
Abstract
Cryo-electron microscopy (cryo-EM) has been widely used to reveal the structures of proteins at atomic resolution. One key challenge is that almost all proteins are predominantly adsorbed to the air-water interface during standard cryo-EM specimen preparation. The interaction of proteins with air-water interface will significantly impede the success of reconstruction and achievable resolution. Here, we highlight the critical role of impenetrable surfactant monolayers in passivating the air-water interface problems, and develop a robust effective method for high-resolution cryo-EM analysis, by using the superstructure GSAMs which comprises surfactant self-assembled monolayers (SAMs) and graphene membrane. The GSAMs works well in enriching the orientations and improving particle utilization ratio of multiple proteins, facilitating the 3.3-Å resolution reconstruction of a 100-kDa protein complex (ACE2-RBD), which shows strong preferential orientation using traditional specimen preparation protocol. Additionally, we demonstrate that GSAMs enables the successful determinations of small proteins (<100 kDa) at near-atomic resolution. This study expands the understanding of SAMs and provides a key to better control the interaction of protein with air-water interface.
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Affiliation(s)
- Liming Zheng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jie Xu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, 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
| | - Weihua Wang
- China Academy of Aerospace Science and Innovation, Beijing, 100088, China
| | - Xiaoyin Gao
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Chao Zhao
- Faculty of Materials Science and Energy Engineering, Shenzhen University of Advanced Technology, Shenzhen, 518055, China.
- Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518103, China.
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
| | - Weijun Guo
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Luzhao Sun
- Beijing Graphene Institute (BGI), Beijing, 100095, China
| | - Hang Cheng
- Shuimu BioSciences Ltd, Beijing, 100089, China
| | - Fanhao Meng
- Shuimu BioSciences Ltd, Beijing, 100089, China
| | - Buhang Chen
- Beijing Graphene Institute (BGI), Beijing, 100095, China
| | - Weiyu Sun
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Xia Jia
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, 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
| | - Xiong Zhou
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Kai Wu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Zhongfan Liu
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Beijing Graphene Institute (BGI), Beijing, 100095, China
| | - Feng Ding
- Faculty of Materials Science and Energy Engineering, Shenzhen University of Advanced Technology, Shenzhen, 518055, China
- Shenzhen Institute of Advanced Electronic Materials, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518103, China
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- School of Biological Sciences, The University of Hong Kong, Hong Kong, 999077, China.
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, 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.
| | - Hailin Peng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
- Beijing Graphene Institute (BGI), Beijing, 100095, China.
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China.
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3
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Yadav S, Vinothkumar KR. Factors affecting macromolecule orientations in thin films formed in cryo-EM. Acta Crystallogr D Struct Biol 2024; 80:535-550. [PMID: 38935342 PMCID: PMC11220838 DOI: 10.1107/s2059798324005229] [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: 11/20/2023] [Accepted: 06/01/2024] [Indexed: 06/28/2024] Open
Abstract
The formation of a vitrified thin film embedded with randomly oriented macromolecules is an essential prerequisite for cryogenic sample electron microscopy. Most commonly, this is achieved using the plunge-freeze method first described nearly 40 years ago. Although this is a robust method, the behaviour of different macromolecules shows great variation upon freezing and often needs to be optimized to obtain an isotropic, high-resolution reconstruction. For a macromolecule in such a film, the probability of encountering the air-water interface in the time between blotting and freezing and adopting preferred orientations is very high. 3D reconstruction using preferentially oriented particles often leads to anisotropic and uninterpretable maps. Currently, there are no general solutions to this prevalent issue, but several approaches largely focusing on sample preparation with the use of additives and novel grid modifications have been attempted. In this study, the effect of physical and chemical factors on the orientations of macromolecules was investigated through an analysis of selected well studied macromolecules, and important parameters that determine the behaviour of proteins on cryo-EM grids were revealed. These insights highlight the nature of the interactions that cause preferred orientations and can be utilized to systematically address orientation bias for any given macromolecule and to provide a framework to design small-molecule additives to enhance sample stability and behaviour.
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Affiliation(s)
- Swati Yadav
- National Centre for Biological SciencesTata Institute of Fundamental ResearchGKVK Post, Bellary RoadBengaluru560 065India
| | - Kutti R. Vinothkumar
- National Centre for Biological SciencesTata Institute of Fundamental ResearchGKVK Post, Bellary RoadBengaluru560 065India
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4
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Liu N, Wang HW. Graphene in cryo-EM specimen optimization. Curr Opin Struct Biol 2024; 86:102823. [PMID: 38688075 DOI: 10.1016/j.sbi.2024.102823] [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: 02/03/2024] [Revised: 03/16/2024] [Accepted: 04/06/2024] [Indexed: 05/02/2024]
Abstract
Specimen preparation is a critical but challenging step in high-resolution cryogenic electron microscopy (cryo-EM) structural analysis of macromolecules. In the past decade, graphene has gained much recognition as the supporting substrate to optimize cryo-EM specimen preparation. It improves macromolecule embedding in ice, reduces beam-induced motion, while imposing negligible background noise. Various types of graphene-coated cryo-EM grids were implemented to improve the robustness and efficiency of specimen preparation. Graphene functionalization by different means has been proved specifically useful in addressing challenges related to the air-water interface (AWI), such as preferential orientation and sample denaturation. Graphene sandwich specimen preparation sets a new direction to explore in cryo-EM analysis of biological specimens. In this review, we discuss the current challenges and future prospects of graphene application in cryo-EM analysis of macromolecules.
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Affiliation(s)
- Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
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5
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Liu YT, Fan H, Hu JJ, Zhou ZH. Overcoming the preferred orientation problem in cryoEM with self-supervised deep-learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.11.588921. [PMID: 38645074 PMCID: PMC11030451 DOI: 10.1101/2024.04.11.588921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
While advances in single-particle cryoEM have enabled the structural determination of macromolecular complexes at atomic resolution, particle orientation bias (the so-called "preferred" orientation problem) remains a complication for most specimens. Existing solutions have relied on biochemical and physical strategies applied to the specimen and are often complex and challenging. Here, we develop spIsoNet, an end-to-end self-supervised deep-learning-based software to address the preferred orientation problem. Using preferred-orientation views to recover molecular information in under-sampled views, spIsoNet improves both angular isotropy and particle alignment accuracy during 3D reconstruction. We demonstrate spIsoNet's capability of generating near-isotropic reconstructions from representative biological systems with limited views, including ribosomes, β-galactosidases, and a previously intractable hemagglutinin trimer dataset. spIsoNet can also be generalized to improve map isotropy and particle alignment of preferentially oriented molecules in subtomogram averaging. Therefore, without additional specimen-preparation procedures, spIsoNet provides a general computational solution to the preferred orientation problem.
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Affiliation(s)
- Yun-Tao Liu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Hongcheng Fan
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Jason J. Hu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
- Current address: Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Z. Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
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6
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Sanchez-Garcia R, Gaullier G, Cuadra-Troncoso JM, Vargas J. Cryo-EM Map Anisotropy Can Be Attenuated by Map Post-Processing and a New Method for Its Estimation. Int J Mol Sci 2024; 25:3959. [PMID: 38612769 PMCID: PMC11012471 DOI: 10.3390/ijms25073959] [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: 02/22/2024] [Revised: 03/22/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
One of the most important challenges in cryogenic electron microscopy (cryo-EM) is the substantial number of samples that exhibit preferred orientations, which leads to an uneven coverage of the projection sphere. As a result, the overall quality of the reconstructed maps can be severely affected, as manifested by the presence of anisotropy in the map resolution. Several methods have been proposed to measure the directional resolution of maps in tandem with experimental protocols to address the problem of preferential orientations in cryo-EM. Following these works, in this manuscript we identified one potential limitation that may affect most of the existing methods and we proposed an alternative approach to evaluate the presence of preferential orientations in cryo-EM reconstructions. In addition, we also showed that some of the most recently proposed cryo-EM map post-processing algorithms can attenuate map anisotropy, thus offering alternative visualization opportunities for cases affected by moderate levels of preferential orientations.
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Affiliation(s)
- Ruben Sanchez-Garcia
- Department of Statistics, University of Oxford, 24–29 St Giles’, Oxford OX1 3LB, UK
| | - Guillaume Gaullier
- Department of Chemistry—Ångström, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden;
| | - Jose Manuel Cuadra-Troncoso
- Departamento de Inteligencia Artificial, Universidad Nacional de Educación a Distancia, C. Juan del Rosal 16, 28040 Madrid, Spain;
| | - Javier Vargas
- Departamento de Óptica, Universidad Complutense de Madrid, Plaza de Ciencias 1, 28040 Madrid, Spain
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7
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Marie Haynes R, Myers J, López CS, Evans J, Davulcu O, Yoshioka C. A strategic approach for efficient cryo-EM grid optimization using design of experiments. J Struct Biol 2024:108068. [PMID: 38364988 DOI: 10.1016/j.jsb.2024.108068] [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: 11/13/2023] [Revised: 01/26/2024] [Accepted: 02/13/2024] [Indexed: 02/18/2024]
Abstract
In recent years, cryo-electron microscopy (cryo-EM) has become a practical and effective method of determining structures at previously unattainable resolutions due to advances in detection, automation, and data processing. However, sample preparation remains a major bottleneck in the cryo-EM workflow. Even after the arduous process of biochemical sample optimization, it often takes several iterations of grid vitrification and screening to determine the optimal grid freezing parameters that yield suitable ice thickness and particle distribution for data collection. Since a high-quality sample is imperative for high-resolution structure determination, grid optimization is a vital step. For researchers who rely on cryo-EM facilities for grid screening, each iteration of this optimization process may delay research progress by a matter of months. Therefore, a more strategic and efficient approach should be taken to ensure that the grid optimization process can be completed in as few iterations as possible. Here, we present an implementation of Design of Experiments (DOE) to expedite and strategize the grid optimization process. A Fractional Factorial Design (FFD) guides the determination of a limited set of experimental conditions which can model the full parameter space of interest. Grids are frozen with these conditions and screened for particle distribution and ice thickness. Quantitative scores are assigned to each of these grid characteristics based on a qualitative rubric. Input conditions and response scores are used to generate a least-squares regression model of the parameter space in JMP, which is used to determine the conditions which should, in theory, yield optimal grids. Upon testing this approach on apoferritin and L-glutamate dehydrogenase on both the Vitrobot Mark IV and the Leica GP2 plunge freezers, the resulting grid conditions reliably yielded grids with high-quality ice and particle distribution that were suitable for collecting large overnight datasets on a Krios. We conclude that a DOE-based approach is a cost-effective and time-saving tool for cryo-EM grid preparation.
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Affiliation(s)
- Rose Marie Haynes
- Pacific Northwest Center for Cryo-Electron Microscopy, Oregon Health & Science University, Portland, OR 97201, USA; Pacific Northwest National Laboratory, Richland, WA 99354, USA.
| | - Janette Myers
- Pacific Northwest Center for Cryo-Electron Microscopy, Oregon Health & Science University, Portland, OR 97201, USA
| | - Claudia S López
- Pacific Northwest Center for Cryo-Electron Microscopy, Oregon Health & Science University, Portland, OR 97201, USA
| | - James Evans
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Omar Davulcu
- Pacific Northwest Center for Cryo-Electron Microscopy, Oregon Health & Science University, Portland, OR 97201, USA
| | - Craig Yoshioka
- Pacific Northwest Center for Cryo-Electron Microscopy, Oregon Health & Science University, Portland, OR 97201, USA
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8
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Song B, Wang W, Jia C, Han Z, Yang J, Yang J, Wu Z, Xu H, Qiao M. Identification and Characterization of a Predominant Hydrophobin in the Edible Mushroom Grifola frondosa. J Fungi (Basel) 2023; 10:25. [PMID: 38248935 PMCID: PMC10820438 DOI: 10.3390/jof10010025] [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: 11/25/2023] [Revised: 12/27/2023] [Accepted: 12/27/2023] [Indexed: 01/23/2024] Open
Abstract
Hydrophobins (HFBs) are a group of small, secreted amphipathic proteins of fungi with multiple physiological functions and potential commercial applications. In this study, HFB genes of the edible mushroom, Grifola frondosa, were systematically identified and characterized, and their transcriptional profiles during fungal development were determined. In total, 19 typical class I HFB genes were discovered and bioinformatically analyzed. Gene expression profile examination showed that Gf.hyd9954 was particularly highly upregulated during primordia formation, suggesting its major role as the predominant HFB in the lifecycle of G. frondosa. The wettability alteration profile and the surface modification ability of recombinant rGf.hyd9954 were greater than for the Grifola HFB HGFII-his. rGf.hyd9954 was also demonstrated to form the typical class I HFB characteristic-rodlet bundles. In addition, rGf.hyd9954 was shown to possess nanoparticle characteristics and emulsification activities. This research sheds light on the regulation of fungal development and its association with the expression of HFB genes.
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Affiliation(s)
- Bo Song
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Wenjun Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Chunhui Jia
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Zhiqiang Han
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Jiyuan Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Jiuxia Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Zhenzhou Wu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Haijin Xu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
| | - Mingqiang Qiao
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300110, China; (B.S.)
- School of Life Science, Shanxi University, Taiyuan 030000, China
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9
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Kang JS, Zhou X, Liu YT, Wang K, Zhou ZH. Theoretical framework and experimental solution for the air-water interface adsorption problem in cryoEM. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.23.541984. [PMID: 37961330 PMCID: PMC10634880 DOI: 10.1101/2023.05.23.541984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
As cryogenic electron microscopy (cryoEM) gains traction in the structural biology community as a method of choice for determining atomic structures of biological complexes, it has been increasingly recognized that many complexes that behave well under conventional negative-stain electron microscopy tend to have preferential orientation, aggregate or simply mysteriously "disappear" on cryoEM grids, but the reasons for such misbehavior are not well understood, limiting systematic approaches to solving the problem. Here, we have developed a theoretical formulation that explains these observations. Our formulation predicts that all particles migrate to the air-water interface (AWI) to lower the total potential surface energy - rationalizing the use of surfactant, which is a direct solution to reducing the surface tension of the aqueous solution. By conducting cryogenic electron tomography (cryoET) with the widely-tested sample, GroEL, we demonstrate that, in a standard buffer solution, nearly all particles migrate to the AWI. Gradual reduction of the surface tension by introducing surfactants decreased the percentage of particles exposed to the surface. By conducting single-particle cryoEM, we confirm that applicable surfactants do not damage the biological complex, thus suggesting that they might offer a practical, simple, and general solution to the problem for high-resolution cryoEM. Application of this solution to a real-world AWI adsorption problem with a more challenging membrane protein, namely, the ClC-1 channel, has led to its first near-atomic structure using cryoEM.
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10
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Nolle F, Starke LJ, Griffo A, Lienemann M, Jacobs K, Seemann R, Fleury JB, Hub JS, Hähl H. Hydrophobin Bilayer as Water Impermeable Protein Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:13790-13800. [PMID: 37726241 PMCID: PMC10552762 DOI: 10.1021/acs.langmuir.3c01006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/24/2023] [Indexed: 09/21/2023]
Abstract
One of the most important properties of membranes is their permeability to water and other small molecules. A targeted change in permeability allows the passage of molecules to be controlled. Vesicles made of membranes with low water permeability are preferable for drug delivery, for example, because they are more stable and maintain the drug concentration inside. This study reports on the very low water permeability of pure protein membranes composed of a bilayer of the amphiphilic protein hydrophobin HFBI. Using a droplet interface bilayer setup, we demonstrate that HFBI bilayers are essentially impermeable to water. HFBI bilayers withstand far larger osmotic pressures than lipid membranes. Only by disturbing the packing of the proteins in the HFBI bilayer is a measurable water permeability induced. To investigate possible molecular mechanisms causing the near-zero permeability, we used all-atom molecular dynamics simulations of various HFBI bilayer models. The simulations suggest that the experimental HFBI bilayer permeability is compatible neither with a lateral honeycomb structure, as found for HFBI monolayers, nor with a residual oil layer within the bilayer or with a disordered lateral packing similar to the packing in lipid bilayers. These results suggest that the low permeabilities of HFBI and lipid bilayers rely on different mechanisms. With their extremely low but adaptable permeability and high stability, HFBI membranes could be used as an osmotic pressure-insensitive barrier in situations where lipid membranes fail such as desalination membranes.
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Affiliation(s)
- Friederike Nolle
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Leonhard J. Starke
- Department
of Theoretical Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Alessandra Griffo
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
- Max
Planck School, Matter to Life, Jahnstraße 29, 69120 Heidelberg, Germany
- Max
Planck Institute for Medical Research Heidelberg, 69120 Heidelberg, Germany
| | | | - Karin Jacobs
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
- Max
Planck School, Matter to Life, Jahnstraße 29, 69120 Heidelberg, Germany
| | - Ralf Seemann
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Jean-Baptiste Fleury
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Jochen S. Hub
- Department
of Theoretical Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Hendrik Hähl
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
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11
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Białobrzewski MK, Klepka BP, Michaś A, Cieplak-Rotowska MK, Staszałek Z, Niedźwiecka A. Diversity of hydrodynamic radii of intrinsically disordered proteins. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2023; 52:607-618. [PMID: 37831084 PMCID: PMC10618399 DOI: 10.1007/s00249-023-01683-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/08/2023] [Accepted: 09/06/2023] [Indexed: 10/14/2023]
Abstract
Intrinsically disordered proteins (IDPs) form an important class of biomolecules regulating biological processes in higher organisms. The lack of a fixed spatial structure facilitates them to perform their regulatory functions and allows the efficiency of biochemical reactions to be controlled by temperature and the cellular environment. From the biophysical point of view, IDPs are biopolymers with a broad configuration state space and their actual conformation depends on non-covalent interactions of its amino acid side chain groups at given temperature and chemical conditions. Thus, the hydrodynamic radius (Rh) of an IDP of a given polymer length (N) is a sequence- and environment-dependent variable. We have reviewed the literature values of hydrodynamic radii of IDPs determined experimentally by SEC, AUC, PFG NMR, DLS, and FCS, and complement them with our FCS results obtained for a series of protein fragments involved in the regulation of human gene expression. The data collected herein show that the values of hydrodynamic radii of IDPs can span the full space between the folded globular and denatured proteins in the Rh(N) diagram.
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Affiliation(s)
- Michał K Białobrzewski
- Laboratory of Biological Physics, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668, Warsaw, Poland
| | - Barbara P Klepka
- Laboratory of Biological Physics, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668, Warsaw, Poland
| | - Agnieszka Michaś
- Laboratory of Biological Physics, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668, Warsaw, Poland
| | - Maja K Cieplak-Rotowska
- Laboratory of Biological Physics, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668, Warsaw, Poland
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093, Warsaw, Poland
- The International Institute of Molecular Mechanisms and Machines, Polish Academy of Sciences, Flisa 6, PL-02247, Warsaw, Poland
| | - Zuzanna Staszałek
- Laboratory of Biological Physics, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668, Warsaw, Poland
| | - Anna Niedźwiecka
- Laboratory of Biological Physics, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668, Warsaw, Poland.
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12
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Kang JS, Zhou X, Liu YT, Wang K, Zhou ZH. Theoretical framework and experimental solution for the air-water interface adsorption problem in cryoEM. BIOPHYSICS REPORTS 2023; 9:215-229. [PMID: 38516618 PMCID: PMC10951471 DOI: 10.52601/bpr.2023.230008] [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: 10/07/2023] [Accepted: 10/31/2023] [Indexed: 03/23/2024] Open
Abstract
As cryogenic electron microscopy (cryoEM) gains traction in the structural biology community as a method of choice for determining atomic structures of biological complexes, it has been increasingly recognized that many complexes that behave well under conventional negative-stain electron microscopy tend to have preferential orientation, aggregate or simply mysteriously "disappear" on cryoEM grids. However, the reasons for such misbehavior are not well understood, which limits systematic approaches to solving the problem. Here, we have developed a theoretical formulation that explains these observations. Our formulation predicts that all particles migrate to the air-water interface (AWI) to lower the total potential surface energy-rationalizing the use of surfactant, which is a direct solution to reduce the surface tension of the aqueous solution. By performing cryogenic electron tomography (cryoET) on the widely-tested sample, GroEL, we demonstrate that, in a standard buffer solution, nearly all particles migrate to the AWI. Gradually reducing the surface tension by introducing surfactants decreased the percentage of particles exposed to the surface. By conducting single-particle cryoEM, we confirm that suitable surfactants do not damage the biological complex, thus suggesting that they might provide a practical, simple, and general solution to the problem for high-resolution cryoEM. Applying this solution to a real-world AWI adsorption problem involving a more challenging membrane protein, namely, the ClC-1 channel, has resulted in its near-atomic structure determination using cryoEM.
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Affiliation(s)
- Joon S. Kang
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
| | - Xueting Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Yun-Tao Liu
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA 90095, USA
| | - Kaituo Wang
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA 90095, USA
| | - Z. Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
- California NanoSystems Institute, UCLA, Los Angeles, CA 90095, USA
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13
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Han BG, Avila-Sakar A, Remis J, Glaeser RM. Challenges in making ideal cryo-EM samples. Curr Opin Struct Biol 2023; 81:102646. [PMID: 37392555 DOI: 10.1016/j.sbi.2023.102646] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 06/02/2023] [Accepted: 06/02/2023] [Indexed: 07/03/2023]
Abstract
Recognizing that interaction with the air-water interface (AWI) is a major challenge for cryo-EM, we first review current approaches designed to avoid it. Of these, immobilizing particles on affinity grids is arguably the most promising. In addition, we review efforts to gain more reliable control of the sample thicknesses, not the least important reason being to prevent immobilized particles from coming in contact with the AWI of the remaining buffer. It is emphasized that avoiding such a contact is as important for cryo-ET as for single-particle cryo-EM. Finally, looking to the future, it is proposed that immobilized samples might be used to perform time-resolved biochemical experiments directly on EM grids rather than just in test tubes or cuvettes.
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Affiliation(s)
- Bong-Gyoon Han
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
| | - Agustin Avila-Sakar
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
| | - Jonathan Remis
- Department of Physics, University of California, Berkeley, CA 94720, USA
| | - Robert M Glaeser
- Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA.
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14
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Cao YY, Chen YY, Wang MS, Tong JJ, Xu M, Zhao C, Lin HY, Mei LC, Dong J, Zhang WL, Qin YX, Huang W, Zhang D, Yang GF. A catalase inhibitor: Targeting the NADPH-binding site for castration-resistant prostate cancer therapy. Redox Biol 2023; 63:102751. [PMID: 37216701 DOI: 10.1016/j.redox.2023.102751] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 04/29/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023] Open
Abstract
Catalase (CAT) is an important antioxidant enzyme that breaks down H2O2 into water and oxygen. Inhibitor-modulating CAT activity in cancer cells is emerging as a potential anticancer strategy. However, the discovery of CAT inhibitors towards the heme active center located at the bottom of long and narrow channel has made little progress. Therefore, targeting new binding site is of great importance for the development of efficient CAT inhibitors. Here, the first NADPH-binding site inhibitor of CAT, BT-Br, was designed and synthesized successfully. The cocrystal structure of BT-Br-bound CAT complex was determined with a resolution of 2.2 Å (PDB ID:8HID), which showed clearly that BT-Br bound at the NADPH-binding site. Furthermore, BT-Br was demonstrated to induce ferroptosis in castration-resistant prostate cancer (CRPC) DU145 cells and eventually reduce CRPC tumors in vivo effectively. The work indicates that CAT has potential as a novel target for CRPC therapy based on ferroptosis inducing.
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Affiliation(s)
- Ya Ya Cao
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Yuan Yuan Chen
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Ming Shu Wang
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Jing Jing Tong
- School of Life Sciences, Central China Normal University, Wuhan, 430079, PR China
| | - Meng Xu
- School of Life Sciences, Central China Normal University, Wuhan, 430079, PR China
| | - Chi Zhao
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Hong Yan Lin
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Long Can Mei
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Jin Dong
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Wen Lin Zhang
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Yu Xuan Qin
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Wei Huang
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China
| | - Dan Zhang
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China.
| | - Guang Fu Yang
- National Key Laboratory of Green Pesticide, International Joint Research Center for Intelligent Biosensor Technology and Health, Central China Normal University, Wuhan, 430079, PR China.
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15
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Zheng L, Liu N, Gao X, Zhu W, Liu K, Wu C, Yan R, Zhang J, Gao X, Yao Y, Deng B, Xu J, Lu Y, Liu Z, Li M, Wei X, Wang HW, Peng H. Uniform thin ice on ultraflat graphene for high-resolution cryo-EM. Nat Methods 2023; 20:123-130. [PMID: 36522503 PMCID: PMC9834055 DOI: 10.1038/s41592-022-01693-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 10/20/2022] [Indexed: 12/23/2022]
Abstract
Cryo-electron microscopy (cryo-EM) visualizes the atomic structure of macromolecules that are embedded in vitrified thin ice at their close-to-native state. However, the homogeneity of ice thickness, a key factor to ensure high image quality, is poorly controlled during specimen preparation and has become one of the main challenges for high-resolution cryo-EM. Here we found that the uniformity of thin ice relies on the surface flatness of the supporting film, and developed a method to use ultraflat graphene (UFG) as the support for cryo-EM specimen preparation to achieve better control of vitreous ice thickness. We show that the uniform thin ice on UFG improves the image quality of vitrified specimens. Using such a method we successfully determined the three-dimensional structures of hemoglobin (64 kDa), α-fetoprotein (67 kDa) with no symmetry, and streptavidin (52 kDa) at a resolution of 3.5 Å, 2.6 Å and 2.2 Å, respectively. Furthermore, our results demonstrate the potential of UFG for the fields of cryo-electron tomography and structure-based drug discovery.
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Affiliation(s)
- 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, China
- Beijing Graphene Institute (BGI), Beijing, China
| | - Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
| | - Xiaoyin Gao
- 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, China
| | - Wenqing Zhu
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China
| | - Kun Liu
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, China
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Cang Wu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Rui Yan
- Beijing Graphene Institute (BGI), Beijing, China
| | - Jincan Zhang
- 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, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Xin Gao
- 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, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yating Yao
- 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, China
| | - Bing Deng
- 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, China
| | - Jie Xu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | - Ye Lu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | - Zhongmin Liu
- Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Mengsen Li
- Hainan Provincial Key Laboratory of Carcinogenesis and Intervention, Hainan Medical College, Haikou, China
| | - Xiaoding Wei
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing, China.
- Beijing Innovation Center for Engineering Science and Advanced Technology, Peking University, Beijing, China.
- Peking University Nanchang Innovation Institute, Nanchang, China.
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing, 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, China.
- Beijing Graphene Institute (BGI), Beijing, China.
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
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16
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Liu N, Wang HW. Better Cryo-EM Specimen Preparation: How to Deal with the Air-Water Interface? J Mol Biol 2022; 435:167926. [PMID: 36563741 DOI: 10.1016/j.jmb.2022.167926] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/08/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022]
Abstract
Cryogenic electron microscopy (cryo-EM) is now one of the most powerful and widely used methods to determine high-resolution structures of macromolecules. A major bottleneck of cryo-EM is to prepare high-quality vitrified specimen, which still faces many practical challenges. During the conventional vitrification process, macromolecules tend to adsorb at the air-water interface (AWI), which is known unfriendly to biological samples. In this review, we outline the nature of AWI and the problems caused by it, such as unpredictable or uneven particle distribution, protein denaturation, dissociation of complex and preferential orientation. We review and discuss the approaches and underlying mechanisms to deal with AWI: 1) Additives, exemplified by detergents, forming a protective layer at AWI and thus preserving the native folds of target macromolecules. 2) Fast vitrification devices based on the idea to freeze in-solution macromolecules before their touching of AWI. 3) Thin layer of continuous supporting films to adsorb macromolecules, and when functionalized with affinity ligands, to specifically anchor the target particles away from the AWI. Among these supporting films, graphene, together with its derivatives, with negligible background noise and mechanical robustness, has emerged as a new generation of support. These strategies have been proven successful in various cases and enable us a better handling of the problems caused by the AWI in cryo-EM specimen preparation.
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Affiliation(s)
- Nan Liu
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structures, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hong-Wei Wang
- Ministry of Education Key Laboratory of Protein Sciences, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structures, School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.
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17
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Zhang W, Xiang Y, Xu W. Probing protein higher-order structures by native capillary electrophoresis-mass spectrometry. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Rima L, Zimmermann M, Fränkl A, Clairfeuille T, Lauer M, Engel A, Engel HA, Braun T. cryoWriter: a blotting free cryo-EM preparation system with a climate jet and cover-slip injector. Faraday Discuss 2022; 240:55-66. [PMID: 35924676 PMCID: PMC9641993 DOI: 10.1039/d2fd00066k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Electron microscopy (EM) introduced a fast and lasting change to structural and cellular biology. However, the sample preparation is still the bottleneck in the cryogenic electron microscopy (cryo-EM) workflow. Classical specimen preparation methods employ a harsh paper-blotting step, and the protein particles are exposed to a damaging air-water interface. Therefore, improved preparation strategies are urgently needed. Here, we present an amended microfluidic sample preparation method, which entirely avoids paper blotting and allows the passivation of the air-water interface during the preparation process. First, a climate jet excludes oxygen from the sample environment and controls the preparation temperature by varying the relative humidity of the grid environment. Second, the integrated "coverslip injector" allows the modulation of the air-water interface of the thin sample layer with effector molecules. We will briefly discuss the climate jet's effect on the stability and dynamics of the sample thin films. Furthermore, we will address the coverslip injector and demonstrate significant improvement in the sample quality.
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Affiliation(s)
- Luca Rima
- Biozentrum, University of BaselSpitalstrasse 414056 BaselSwitzerland+41 79 7337269
| | - Michael Zimmermann
- Biozentrum, University of BaselSpitalstrasse 414056 BaselSwitzerland+41 79 7337269
| | - Andri Fränkl
- Swiss Nanoscience Institute, University of Basel4056 BaselSwitzerland
| | - Thomas Clairfeuille
- Roche Pharma Research and Early Development, Therapeutic Modalities, Lead Discovery, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd.Grenzacherstrasse 1244070 BaselSwitzerland
| | - Matthias Lauer
- Roche Pharma Research and Early Development, Therapeutic Modalities, Lead Discovery, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd.Grenzacherstrasse 1244070 BaselSwitzerland
| | - Andreas Engel
- cryoWrite Ltd.Klingelbergstrasse 504056 BaselSwitzerland
| | | | - Thomas Braun
- Biozentrum, University of BaselSpitalstrasse 414056 BaselSwitzerland+41 79 7337269
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19
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Hrebík D, Gondová M, Valentová L, Füzik T, Přidal A, Nováček J, Plevka P. Polyelectrolyte coating of cryo-EM grids improves lateral distribution and prevents aggregation of macromolecules. Acta Crystallogr D Struct Biol 2022; 78:1337-1346. [PMID: 36322417 PMCID: PMC9629489 DOI: 10.1107/s2059798322009299] [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: 06/09/2022] [Accepted: 09/21/2022] [Indexed: 11/06/2022] Open
Abstract
Cryo-electron microscopy (cryo-EM) is one of the primary methods used to determine the structures of macromolecules and their complexes. With the increased availability of cryo-electron microscopes, the preparation of high-quality samples has become a bottleneck in the cryo-EM structure-determination pipeline. Macromolecules can be damaged during the purification or preparation of vitrified samples for cryo-EM, making them prone to binding to the grid support, to aggregation or to the adoption of preferential orientations at the air-water interface. Here, it is shown that coating cryo-EM grids with a negatively charged polyelectrolyte, such as single-stranded DNA, before applying the sample reduces the aggregation of macromolecules and improves their distribution. The single-stranded DNA-coated grids enabled the determination of high-resolution structures from samples that aggregated on conventional grids. The polyelectrolyte coating reduces the diffusion of macromolecules and thus may limit the negative effects of the contact of macromolecules with the grid support and blotting paper, as well as of the shear forces on macromolecules during grid blotting. Coating grids with polyelectrolytes can readily be employed in any laboratory dealing with cryo-EM sample preparation, since it is fast, simple, inexpensive and does not require specialized equipment.
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Affiliation(s)
- Dominik Hrebík
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Mária Gondová
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Lucie Valentová
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Tibor Füzik
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Antonín Přidal
- Faculty of Agronomy, Mendel University in Brno, Zemědělská 1, 613 00 Brno, Czech Republic
| | - Jiří Nováček
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Pavel Plevka
- Central European Institute of Technology, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
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20
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Aleshin VA, Bunik VI, Bruch EM, Bellinzoni M. Structural Basis for the Binding of Allosteric Activators Leucine and ADP to Mammalian Glutamate Dehydrogenase. Int J Mol Sci 2022; 23:ijms231911306. [PMID: 36232607 PMCID: PMC9570180 DOI: 10.3390/ijms231911306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 09/19/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022] Open
Abstract
Glutamate dehydrogenase (GDH) plays a key role in the metabolism of glutamate, an important compound at a cross-road of carbon and nitrogen metabolism and a relevant neurotransmitter. Despite being one of the first discovered allosteric enzymes, GDH still poses challenges for structural characterization of its allosteric sites. Only the structures with ADP, and at low (3.5 Å) resolution, are available for mammalian GDH complexes with allosteric activators. Here, we aim at deciphering a structural basis for the GDH allosteric activation using bovine GDH as a model. For the first time, we report a mammalian GDH structure in a ternary complex with the activators leucine and ADP, co-crystallized with potassium ion, resolved to 2.45 Å. An improved 2.4-angstrom resolution of the GDH complex with ADP is also presented. The ternary complex with leucine and ADP differs from the binary complex with ADP by the conformation of GDH C-terminus, involved in the leucine binding and subunit interactions. The potassium site, identified in this work, may mediate interactions between the leucine and ADP binding sites. Our data provide novel insights into the mechanisms of GDH activation by leucine and ADP, linked to the enzyme regulation by (de)acetylation.
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Affiliation(s)
- Vasily A. Aleshin
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Department of Biochemistry, Sechenov University, 119048 Moscow, Russia
| | - Victoria I. Bunik
- Department of Biokinetics, A. N. Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Department of Biochemistry, Sechenov University, 119048 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119234 Moscow, Russia
- Correspondence: (V.I.B.); (M.B.); Tel.: +7-495-9394484 (V.I.B.); +33-1-45688608 (M.B.)
| | - Eduardo M. Bruch
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Unité de Microbiologie Structurale, F-75724 Paris, France
| | - Marco Bellinzoni
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Unité de Microbiologie Structurale, F-75724 Paris, France
- Correspondence: (V.I.B.); (M.B.); Tel.: +7-495-9394484 (V.I.B.); +33-1-45688608 (M.B.)
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21
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López-Valiñas Á, Baioni L, Córdoba L, Darji A, Chiapponi C, Segalés J, Ganges L, Núñez JI. Evolution of Swine Influenza Virus H3N2 in Vaccinated and Nonvaccinated Pigs after Previous Natural H1N1 Infection. Viruses 2022; 14:v14092008. [PMID: 36146814 PMCID: PMC9505157 DOI: 10.3390/v14092008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 08/20/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
Swine influenza viruses (SIV) produce a highly contagious and worldwide distributed disease that can cause important economic losses to the pig industry. Currently, this virus is endemic in farms and, although used limitedly, trivalent vaccine application is the most extended strategy to control SIV. The presence of pre-existing immunity against SIV may modulate the evolutionary dynamic of this virus. To better understand these dynamics, the viral variants generated in vaccinated and nonvaccinated H3N2 challenged pigs after recovery from a natural A(H1N1) pdm09 infection were determined and analyzed. In total, seventeen whole SIV genomes were determined, 6 from vaccinated, and 10 from nonvaccinated animals and their inoculum, by NGS. Herein, 214 de novo substitutions were found along all SIV segments, 44 of them being nonsynonymous ones with an allele frequency greater than 5%. Nonsynonymous substitutions were not found in NP; meanwhile, many of these were allocated in PB2, PB1, and NS1 proteins. Regarding HA and NA proteins, higher nucleotide diversity, proportionally more nonsynonymous substitutions with an allele frequency greater than 5%, and different domain allocations of mutants, were observed in vaccinated animals, indicating different evolutionary dynamics. This study highlights the rapid adaptability of SIV in different environments.
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Affiliation(s)
- Álvaro López-Valiñas
- IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), 08193 Barcelona, Spain
| | - Laura Baioni
- WOAH Reference Laboratory for Swine Influenza, Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia-Romagna, 25124 Brescia, Italy
| | - Lorena Córdoba
- IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), 08193 Barcelona, Spain
| | - Ayub Darji
- IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), 08193 Barcelona, Spain
| | - Chiara Chiapponi
- WOAH Reference Laboratory for Swine Influenza, Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia-Romagna, 25124 Brescia, Italy
| | - Joaquim Segalés
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), 08193 Barcelona, Spain
- Departament de Sanitat i Anatomia Animals, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Llilianne Ganges
- IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), 08193 Barcelona, Spain
- WOAH Reference Laboratory for Classical Swine Fever, IRTA-CReSA, 08193 Barcelona, Spain
| | - José I. Núñez
- IRTA, Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- Unitat Mixta d’Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, 08193 Barcelona, Spain
- WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), 08193 Barcelona, Spain
- Correspondence:
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22
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Fan H, Sun F. Developing Graphene Grids for Cryoelectron Microscopy. Front Mol Biosci 2022; 9:937253. [PMID: 35911962 PMCID: PMC9326159 DOI: 10.3389/fmolb.2022.937253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
Cryogenic electron microscopy (cryo-EM) single particle analysis has become one of the major techniques used to study high-resolution 3D structures of biological macromolecules. Specimens are generally prepared in a thin layer of vitrified ice using a holey carbon grid. However, the sample quality using this type of grid is not always ideal for high-resolution imaging even when the specimens in the test tube behave ideally. Various problems occur during a vitrification procedure, including poor/nonuniform distribution of particles, preferred orientation of particles, specimen denaturation/degradation, high background from thick ice, and beam-induced motion, which have become important bottlenecks in high-resolution structural studies using cryo-EM in many projects. In recent years, grids with support films made of graphene and its derivatives have been developed to efficiently solve these problems. Here, the various advantages of graphene grids over conventional holey carbon film grids, functionalization of graphene support films, production methods of graphene grids, and origins of pristine graphene contamination are reviewed and discussed.
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Affiliation(s)
- Hongcheng Fan
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Fei Sun
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Bioland Laboratory, Guangzhou, China
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23
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Yu G, Hao J, Pan X, Shi L, Zhang Y, Wang J, Fan H, Xiao Y, Yang F, Lou J, Chang W, Malnoë A, Li M. Structure of Arabidopsis SOQ1 lumenal region unveils C-terminal domain essential for negative regulation of photoprotective qH. NATURE PLANTS 2022; 8:840-855. [PMID: 35798975 DOI: 10.1038/s41477-022-01177-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Non-photochemical quenching (NPQ) plays an important role for phototrophs in decreasing photo-oxidative damage. qH is a sustained form of NPQ and depends on the plastid lipocalin (LCNP). A thylakoid membrane-anchored protein SUPPRESSOR OF QUENCHING1 (SOQ1) prevents qH formation by inhibiting LCNP. SOQ1 suppresses qH with its lumen-located thioredoxin (Trx)-like and NHL domains. Here we report structural data, genetic modification and biochemical characterization of Arabidopsis SOQ1 lumenal domains. Our results show that the Trx-like and NHL domains are associated together, with the cysteine motif located at their interface. Residue E859, required for SOQ1 function, is pivotal for maintaining the Trx-NHL association. Importantly, the C-terminal region of SOQ1 forms an independent β-stranded domain that has structural homology to the N-terminal domain of bacterial disulfide bond protein D and is essential for negative regulation of qH. Furthermore, SOQ1 is susceptible to cleavage at the loops connecting the neighbouring lumenal domains both in vitro and in vivo, which could be a regulatory process for its suppression function of qH.
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Affiliation(s)
- Guimei Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Jingfang Hao
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Xiaowei Pan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
- College of Life Science, Capital Normal University, Beijing, China
| | - Lifang Shi
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Yong Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Jifeng Wang
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Hongcheng Fan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Yang Xiao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Fuquan Yang
- University of Chinese Academy of Sciences, Beijing, P.R. China
- Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
| | - Jizhong Lou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Wenrui Chang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China
- University of Chinese Academy of Sciences, Beijing, P.R. China
| | - Alizée Malnoë
- Umeå Plant Science Centre (UPSC), Department of Plant Physiology, Umeå University, Umeå, Sweden.
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, P.R. China.
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24
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Zhang X, Jacobeen S, Zhang Q, Khau B, Yunker P, Qi HJ, Bhamla S, Russo PS. Reshaping sub-millimetre bubbles from spheres to tori. SOFT MATTER 2022; 18:4660-4666. [PMID: 35543353 PMCID: PMC9247010 DOI: 10.1039/d2sm00173j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Shape-changing objects are prized for applications ranging from acoustics to robotics. We report sub-millimetre bubbles that reversibly and rapidly change not only their shape but also their topological class, from sphere to torus, when subjected to a simple pressure treatment. Stabilized by a solid-like film of nanoscopic protein "particles", the bubbles may persist in toroidal form for several days, most of them with the relative dimensions expected of Clifford tori. The ability to cross topological classes reversibly and quickly is enabled by the expulsion of protein from the strained surfaces in the form of submicron assemblies. Compared to structural modifications of liquid-filled vesicles, for example by slow changes in solution osmolality, the rapid inducement of shape changes in bubbles by application of pressure may hasten experimental investigations of surface mechanics, even as it suggests new routes to lightweight materials with high surface areas.
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Affiliation(s)
- Xujun Zhang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
- Georgia Tech Polymer Network, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Shane Jacobeen
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Qiang Zhang
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Brian Khau
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Peter Yunker
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - H Jerry Qi
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Saad Bhamla
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Paul S Russo
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
- Georgia Tech Polymer Network, Georgia Institute of Technology, Atlanta, GA 30332, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
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25
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Xu Y, Dang S. Recent Technical Advances in Sample Preparation for Single-Particle Cryo-EM. Front Mol Biosci 2022; 9:892459. [PMID: 35813814 PMCID: PMC9263182 DOI: 10.3389/fmolb.2022.892459] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 05/12/2022] [Indexed: 11/25/2022] Open
Abstract
Cryo-sample preparation is a vital step in the process of obtaining high-resolution structures of macromolecules by using the single-particle cryo–electron microscopy (cryo-EM) method; however, cryo-sample preparation is commonly hampered by high uncertainty and low reproducibility. Specifically, the existence of air-water interfaces during the sample vitrification process could cause protein denaturation and aggregation, complex disassembly, adoption of preferred orientations, and other serious problems affecting the protein particles, thereby making it challenging to pursue high-resolution 3D reconstruction. Therefore, sample preparation has emerged as a critical research topic, and several new methods for application at various preparation stages have been proposed to overcome the aforementioned hurdles. Here, we summarize the methods developed for enhancing the quality of cryo-samples at distinct stages of sample preparation, and we offer insights for developing future strategies based on diverse viewpoints. We anticipate that cryo-sample preparation will no longer be a limiting step in the single-particle cryo-EM field as increasing numbers of methods are developed in the near future, which will ultimately benefit the entire research community.
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Affiliation(s)
- Yixin Xu
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Shangyu Dang
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- Center of Systems Biology and Human Health, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- *Correspondence: Shangyu Dang,
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26
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A label-free lateral offset spliced coreless fiber MZI biosensor based on hydrophobin HGFI for TNF-α detection. OPTOELECTRONICS LETTERS 2022; 18:263-268. [PMID: 35693480 PMCID: PMC9170553 DOI: 10.1007/s11801-022-2061-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 04/24/2022] [Indexed: 11/06/2022]
Abstract
A real-time label-free lateral offset spliced coreless fiber (CF) Mach-Zehnder interferometer (MZI) biosensor functionalized with hydrophobin Grifola frondosa I (HGFI) was proposed for the detection of cytokine tumour necrosis factor alpha (TNF-α). The nanolayer self-assembled on the optical fiber surfaces by HGFI rendered the immobilization of probe TNF-α antibody and recognition of antigen TNF-α. Trifluoroacetic acid was utilized to remove the HGFI layer from the glass surface, which was validated by field emission scanning electron microscopy (FESEM) and water contact angle (WCA). Results demonstrated that the processes of HGFI modification, antibody immobilization and specific antibody detection can be monitored in real time. The proposed biosensor exhibited good specificity, repeatability and low detection limit for TNF-α, extending its application in inflammation and disease monitoring.
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