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Huang Y, Zhang Y, Ni T. Towards in situ high-resolution imaging of viruses and macromolecular complexes using cryo-electron tomography. J Struct Biol 2023; 215:108000. [PMID: 37467823 DOI: 10.1016/j.jsb.2023.108000] [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: 04/25/2023] [Revised: 07/15/2023] [Accepted: 07/16/2023] [Indexed: 07/21/2023]
Abstract
Cryo-electron tomography and subtomogram averaging are rising and fast-evolving imaging techniques to study biological events, providing structural information at an unprecedented resolution while preserving spatial correlation in their native contexts. The latest technology and methodology development ranging from sample preparation to data collection and data processing, has enabled significant advancement in its applications to various biological systems. This review provides an overview of the current technology development enabling high-resolution structural study in situ, highlighting the use of a priori information of biological samples to assess the quality of subtomogram averaging pipeline. We exemplify the applications of this technique to understanding viruses and principles of macromolecule assembly using different biological systems, ranging from in vitro to in situ samples, which provide structural information at different resolutions and contexts.
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Affiliation(s)
- Yixin Huang
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region
| | - Yu Zhang
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region
| | - Tao Ni
- School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region.
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Ma L, Li X, Petersen RB, Peng A, Huang K. Probing the interactions between amyloidogenic proteins and bio-membranes. Biophys Chem 2023; 296:106984. [PMID: 36889133 DOI: 10.1016/j.bpc.2023.106984] [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: 12/22/2022] [Revised: 02/11/2023] [Accepted: 02/22/2023] [Indexed: 03/01/2023]
Abstract
Protein misfolding diseases (PMDs) in humans are characterized by the deposition of protein aggregates in tissues, including Alzheimer's disease, Parkinson's disease, type 2 diabetes, and amyotrophic lateral sclerosis. Misfolding and aggregation of amyloidogenic proteins play a central role in the onset and progression of PMDs, and these processes are regulated by multiple factors, especially the interaction between proteins and bio-membranes. Bio-membranes induce conformational changes in amyloidogenic proteins and affect their aggregation; on the other hand, the aggregates of amyloidogenic proteins may cause membrane damage or dysfunction leading to cytotoxicity. In this review, we summarize the factors that affect the binding of amyloidogenic proteins and membranes, the effects of bio-membranes on the aggregation of amyloidogenic proteins, mechanisms of membrane disruption by amyloidogenic aggregates, technical approaches for detecting these interactions, and finally therapeutic strategies targeting membrane damage caused by amyloidogenic proteins.
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Affiliation(s)
- Liang Ma
- Department of Pharmacy, Wuhan Mental Health Center, Wuhan, China; Department of Pharmacy, Wuhan Hospital for Psychotherapy, Wuhan, China
| | - Xi Li
- Tongji School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Robert B Petersen
- Foundational Sciences, Central Michigan University College of Medicine, Mount Pleasant, MI, USA
| | - Anlin Peng
- Department of Pharmacy, The Third Hospital of Wuhan, Tongren Hospital of Wuhan University, Wuhan, China.
| | - Kun Huang
- Tongji School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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3
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Yu X, Ni T, Munson G, Zhang P, Gilbert RJC. Cryo-EM structures of perforin-2 in isolation and assembled on a membrane suggest a mechanism for pore formation. EMBO J 2022; 41:e111857. [PMID: 36245269 PMCID: PMC9713709 DOI: 10.15252/embj.2022111857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/29/2022] [Accepted: 09/09/2022] [Indexed: 01/15/2023] Open
Abstract
Perforin-2 (PFN2, MPEG1) is a key pore-forming protein in mammalian innate immunity restricting intracellular bacteria proliferation. It forms a membrane-bound pre-pore complex that converts to a pore-forming structure upon acidification; but its mechanism of conformational transition has been debated. Here we used cryo-electron microscopy, tomography and subtomogram averaging to determine structures of PFN2 in pre-pore and pore conformations in isolation and bound to liposomes. In isolation and upon acidification, the pre-assembled complete pre-pore rings convert to pores in both flat ring and twisted conformations. On membranes, in situ assembled PFN2 pre-pores display various degrees of completeness; whereas PFN2 pores are mainly incomplete arc structures that follow the same subunit packing arrangements as found in isolation. Both assemblies on membranes use their P2 β-hairpin for binding to the lipid membrane surface. Overall, these structural snapshots suggest a molecular mechanism for PFN2 pre-pore to pore transition on a targeted membrane, potentially using the twisted pore as an intermediate or alternative state to the flat conformation, with the capacity to cause bilayer distortion during membrane insertion.
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Affiliation(s)
- Xiulian Yu
- Division of Structural Biology, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
- Calleva Research Centre for Evolution and Human Sciences, Magdalen CollegeUniversity of OxfordOxfordUK
| | - Tao Ni
- Division of Structural Biology, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
- Present address:
School of Biomedical Sciences, LKS Faculty of MedicineThe University of Hong KongPokfulamHong Kong SARChina
| | - George Munson
- Department of Microbiology and ImmunologyUniversity of Miami Miller School of MedicineMiamiFLUSA
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
- Diamond Light SourceHarwell Science and Innovation CampusDidcotUK
- Chinese Academy of Medical Sciences Oxford InstituteUniversity of OxfordOxfordUK
| | - Robert J C Gilbert
- Division of Structural Biology, Wellcome Centre for Human GeneticsUniversity of OxfordOxfordUK
- Calleva Research Centre for Evolution and Human Sciences, Magdalen CollegeUniversity of OxfordOxfordUK
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Scott H, Huang W, Andra K, Mamillapalli S, Gonti S, Day A, Zhang K, Mehzabeen N, Battaile KP, Raju A, Lovell S, Bann JG, Taylor DJ. Structure of the anthrax protective antigen D425A dominant negative mutant reveals a stalled intermediate state of pore maturation. J Mol Biol 2022; 434:167548. [PMID: 35304125 DOI: 10.1016/j.jmb.2022.167548] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/01/2022] [Accepted: 03/10/2022] [Indexed: 10/18/2022]
Abstract
The tripartite protein complex produced by anthrax bacteria (Bacillus anthracis) is a member of the AB family of β-barrel pore-forming toxins. The protective antigen (PA) component forms an oligomeric prepore that assembles on the host cell surface and serves as a scaffold for binding of lethal and edema factors. Following endocytosis, the acidic environment of the late endosome triggers a pH-induced conformational rearrangement to promote maturation of the PA prepore to a functional, membrane spanning pore that facilitates delivery of lethal and edema factors to the cytosol of the infected host. Here, we show that the dominant-negative D425A mutant of PA stalls anthrax pore maturation in an intermediate state at acidic pH. Our 2.7 Å cryo-EM structure of the intermediate state reveals structural rearrangements that involve constriction of the oligomeric pore combined with an intramolecular dissociation of the pore-forming module. In addition to defining the early stages of anthrax pore maturation, the structure identifies asymmetric conformational changes in the oligomeric pore that are influenced by the precise configuration of adjacent protomers.
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Affiliation(s)
- Harry Scott
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kiran Andra
- Department of Chemistry, Wichita State University, Wichita, KS 67260, USA
| | | | - Srinivas Gonti
- Department of Chemistry, Wichita State University, Wichita, KS 67260, USA
| | - Alexander Day
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Kaiming Zhang
- Stanford Linear Accelerator Center and the Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Nurjahan Mehzabeen
- Protein Structure Laboratory, University of Kansas, Lawrence, KS 66047, USA
| | - Kevin P Battaile
- IMCA-CAT, APS, Argonne National Laboratory, 9700 South Cass Avenue, Building 435A, Argonne, IL 60439, USA
| | - Anjali Raju
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Scott Lovell
- Protein Structure Laboratory, University of Kansas, Lawrence, KS 66047, USA
| | - James G Bann
- Department of Chemistry, Wichita State University, Wichita, KS 67260, USA.
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA; Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
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Wu F, Jin X, Guan Z, Lin J, Cai C, Wang L, Li Y, Lin S, Xu P, Gao L. Membrane Nanopores Induced by Nanotoroids via an Insertion and Pore-Forming Pathway. NANO LETTERS 2021; 21:8545-8553. [PMID: 34623162 DOI: 10.1021/acs.nanolett.1c01331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The formation of membrane nanopores is one of the crucial activities of cells and has attracted considerable attention. However, the understanding of their types and mechanisms is still limited. Herein, we report a novel nanopore formation phenomenon achieved through the insertion of polymeric nanotoroids into the cellular membrane. As revealed by theoretical simulations, the nanotoroid can embed in the membrane, leaving a nanopore on the cell. The through-the-cavity wrapping of lipids is critical for the retention of the nanotoroid in the membrane, which is attributed to both a relatively large inner cavity of the nanotoroid and a moderate attraction between the nanotoroid and membrane lipids. Under the guidance of the simulation predictions, experiments using polypeptide toroids as pore-forming agents were performed, confirming the unique biophysical phenomenon. This work demonstrates a distinctive pore-forming pathway, deepens the understanding of the membrane nanopore phenomenon, and assists in the design of advanced pore-forming materials.
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Affiliation(s)
- Fangsheng Wu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Xiao Jin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Zhou Guan
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Jiaping Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Chunhua Cai
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Liquan Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Yongsheng Li
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Shaoliang Lin
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Pengfei Xu
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Liang Gao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, People's Republic of China
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