151
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Structural basis for antiarrhythmic drug interactions with the human cardiac sodium channel. Proc Natl Acad Sci U S A 2019; 116:2945-2954. [PMID: 30728299 PMCID: PMC6386684 DOI: 10.1073/pnas.1817446116] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels play a central role in cellular excitability and are key targets for drug development. Recent breakthroughs in high-resolution cryo-electron microscopy protein structure determination, Rosetta computational protein structure modeling, and multimicrosecond molecular dynamics simulations are empowering advances in structural biology to study the atomistic details of channel−drug interactions. We used Rosetta structural computational modeling and molecular dynamics simulations to study the interactions of antiarrhythmic and local anesthetic drugs with cardiac sodium channel. Our results provide crucial atomic-scale mechanistic insights into the channel–drug interactions, necessary for the rational design of novel modulators of the human cardiac sodium channel to be used for the treatment of cardiac arrhythmias. The human voltage-gated sodium channel, hNaV1.5, is responsible for the rapid upstroke of the cardiac action potential and is target for antiarrhythmic therapy. Despite the clinical relevance of hNaV1.5-targeting drugs, structure-based molecular mechanisms of promising or problematic drugs have not been investigated at atomic scale to inform drug design. Here, we used Rosetta structural modeling and docking as well as molecular dynamics simulations to study the interactions of antiarrhythmic and local anesthetic drugs with hNaV1.5. These calculations revealed several key drug binding sites formed within the pore lumen that can simultaneously accommodate up to two drug molecules. Molecular dynamics simulations identified a hydrophilic access pathway through the intracellular gate and a hydrophobic access pathway through a fenestration between DIII and DIV. Our results advance the understanding of molecular mechanisms of antiarrhythmic and local anesthetic drug interactions with hNaV1.5 and will be useful for rational design of novel therapeutics.
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152
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Brown BM, Nguyen HM, Wulff H. Recent advances in our understanding of the structure and function of more unusual cation channels. F1000Res 2019; 8. [PMID: 30755796 PMCID: PMC6354322 DOI: 10.12688/f1000research.17163.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/23/2019] [Indexed: 12/18/2022] Open
Abstract
As their name implies, cation channels allow the regulated flow of cations such as sodium, potassium, calcium, and magnesium across cellular and intracellular membranes. Cation channels have long been known for their fundamental roles in controlling membrane potential and excitability in neurons and muscle. In this review, we provide an update on the recent advances in our understanding of the structure–function relationship and the physiological and pathophysiological role of cation channels. The most exciting developments in the last two years, in our opinion, have been the insights that cryoelectron microscopy has provided into the inner life and the gating of not only voltage-gated channels but also mechanosensitive and calcium- or sodium-activated channels. The mechanosensitive Piezo channels especially have delighted the field not only with a fascinating new type of structure but with important roles in blood pressure regulation and lung function.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Hai M Nguyen
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, USA
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153
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Xu H, Li T, Rohou A, Arthur CP, Tzakoniati F, Wong E, Estevez A, Kugel C, Franke Y, Chen J, Ciferri C, Hackos DH, Koth CM, Payandeh J. Structural Basis of Nav1.7 Inhibition by a Gating-Modifier Spider Toxin. Cell 2019; 176:702-715.e14. [PMID: 30661758 DOI: 10.1016/j.cell.2018.12.018] [Citation(s) in RCA: 112] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 09/11/2018] [Accepted: 12/11/2018] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium (Nav) channels are targets of disease mutations, toxins, and therapeutic drugs. Despite recent advances, the structural basis of voltage sensing, electromechanical coupling, and toxin modulation remains ill-defined. Protoxin-II (ProTx2) from the Peruvian green velvet tarantula is an inhibitor cystine-knot peptide and selective antagonist of the human Nav1.7 channel. Here, we visualize ProTx2 in complex with voltage-sensor domain II (VSD2) from Nav1.7 using X-ray crystallography and cryoelectron microscopy. Membrane partitioning orients ProTx2 for unfettered access to VSD2, where ProTx2 interrogates distinct features of the Nav1.7 receptor site. ProTx2 positions two basic residues into the extracellular vestibule to antagonize S4 gating-charge movement through an electrostatic mechanism. ProTx2 has trapped activated and deactivated states of VSD2, revealing a remarkable ∼10 Å translation of the S4 helix, providing a structural framework for activation gating in voltage-gated ion channels. Finally, our results deliver key templates to design selective Nav channel antagonists.
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Affiliation(s)
- Hui Xu
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Tianbo Li
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, CA 94080, USA.
| | - Alexis Rohou
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
| | | | - Foteini Tzakoniati
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Evera Wong
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA
| | - Alberto Estevez
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - Christine Kugel
- Department of Biomolecular Resources, Genentech, South San Francisco, CA 94080, USA
| | - Yvonne Franke
- Department of Biomolecular Resources, Genentech, South San Francisco, CA 94080, USA
| | - Jun Chen
- Department of Biochemical and Cellular Pharmacology, Genentech, South San Francisco, CA 94080, USA
| | - Claudio Ciferri
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA
| | - David H Hackos
- Department of Neuroscience, Genentech, South San Francisco, CA 94080, USA.
| | - Christopher M Koth
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
| | - Jian Payandeh
- Department of Structural Biology, Genentech, South San Francisco, CA 94080, USA.
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154
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Clark GC, Casewell NR, Elliott CT, Harvey AL, Jamieson AG, Strong PN, Turner AD. Friends or Foes? Emerging Impacts of Biological Toxins. Trends Biochem Sci 2019; 44:365-379. [PMID: 30651181 DOI: 10.1016/j.tibs.2018.12.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/21/2018] [Accepted: 12/07/2018] [Indexed: 12/19/2022]
Abstract
Toxins are substances produced from biological sources (e.g., animal, plants, microorganisms) that have deleterious effects on a living organism. Despite the obvious health concerns of being exposed to toxins, they are having substantial positive impacts in a number of industrial sectors. Several toxin-derived products are approved for clinical, veterinary, or agrochemical uses. This review sets out the case for toxins as 'friends' that are providing the basis of novel medicines, insecticides, and even nucleic acid sequencing technologies. We also discuss emerging toxins ('foes') that are becoming increasingly prevalent in a range of contexts through climate change and the globalisation of food supply chains and that ultimately pose a risk to health.
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Affiliation(s)
- Graeme C Clark
- CBR Division, Defence Science & Technology Laboratory, DSTL - Porton Down, Salisbury, Wiltshire, SP4 0JQ, UK.
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
| | - Christopher T Elliott
- Institute for Global Food Security, School of Biological Sciences, Queen's University, Belfast, 97 Lisburn Road, Belfast, BT9 7BL, UK
| | - Alan L Harvey
- Strathclyde Institute of Pharmacy & Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, UK
| | - Andrew G Jamieson
- School of Chemistry, Joseph Black Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Peter N Strong
- Biomolecular Research Centre, Department of Biosciences and Chemistry, Sheffield Hallam University, Sheffield, S1 1WB, UK
| | - Andrew D Turner
- Food Safety Group, Cefas, Barrack Road, The Nothe, Weymouth, Dorset DT4 8UB, UK
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155
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Samantsidis GR, O'Reilly AO, Douris V, Vontas J. Functional validation of target-site resistance mutations against sodium channel blocker insecticides (SCBIs) via molecular modeling and genome engineering in Drosophila. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 104:73-81. [PMID: 30572019 DOI: 10.1016/j.ibmb.2018.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/14/2018] [Accepted: 12/14/2018] [Indexed: 06/09/2023]
Abstract
Sodium channel blocker insecticides (SCBIs) like indoxacarb and metaflumizone offer an alternative insecticide resistance management (IRM) strategy against several pests that are resistant to other compounds. However, resistance to SCBIs has been reported in several pests, in most cases implicating metabolic resistance mechanisms, although in certain indoxacarb resistant populations of Plutella xylostella and Tuta absoluta, two mutations in the domain IV S6 segment of the voltage-gated sodium channel, F1845Y and V1848I have been identified, and have been postulated through in vitro electrophysiological studies to contribute to target-site resistance. In order to functionally validate in vivo each mutation in the absence of confounding resistance mechanisms, we have employed a CRISPR/Cas9 strategy to generate strains of Drosophila melanogaster bearing homozygous F1845Y or V1848I mutations in the para (voltage-gated sodium channel) gene. We performed toxicity bioassays of these strains compared to wild-type controls of the same genetic background. Our results indicate both mutations confer moderate resistance to indoxacarb (RR: 6-10.2), and V1848I to metaflumizone (RR: 8.4). However, F1845Y confers very strong resistance to metaflumizone (RR: >3400). Our molecular modeling studies suggest a steric hindrance mechanism may account for the resistance of both V1848I and F1845Y mutations, whereby introducing larger side chains may inhibit metaflumizone binding.
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Affiliation(s)
- George-Rafael Samantsidis
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13, Heraklion Crete, Greece; Laboratory of Molecular Entomology, Department of Biology, University of Crete, GR-700 13, Heraklion Crete, Greece
| | - Andrias O O'Reilly
- School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, UK
| | - Vassilis Douris
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13, Heraklion Crete, Greece.
| | - John Vontas
- Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas, 100 N. Plastira Street, GR-700 13, Heraklion Crete, Greece; Laboratory of Pesticide Science, Department of Crop Science, Agricultural University of Athens, 75 Iera Odos Street, GR-11855, Athens, Greece.
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156
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Finol-Urdaneta RK, McArthur JR, Goldschen-Ohm MP, Gaudet R, Tikhonov DB, Zhorov BS, French RJ. Batrachotoxin acts as a stent to hold open homotetrameric prokaryotic voltage-gated sodium channels. J Gen Physiol 2018; 151:186-199. [PMID: 30587506 PMCID: PMC6363421 DOI: 10.1085/jgp.201812278] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/30/2018] [Indexed: 11/20/2022] Open
Abstract
Batrachotoxin (BTX), an alkaloid from skin secretions of dendrobatid frogs, causes paralysis and death by facilitating activation and inhibiting deactivation of eukaryotic voltage-gated sodium (Nav) channels, which underlie action potentials in nerve, muscle, and heart. A full understanding of the mechanism by which BTX modifies eukaryotic Nav gating awaits determination of high-resolution structures of functional toxin-channel complexes. Here, we investigate the action of BTX on the homotetrameric prokaryotic Nav channels NaChBac and NavSp1. By combining mutational analysis and whole-cell patch clamp with molecular and kinetic modeling, we show that BTX hinders deactivation and facilitates activation in a use-dependent fashion. Our molecular model shows the horseshoe-shaped BTX molecule bound within the open pore, forming hydrophobic H-bonds and cation-π contacts with the pore-lining helices, leaving space for partially dehydrated sodium ions to permeate through the hydrophilic inner surface of the horseshoe. We infer that bulky BTX, bound at the level of the gating-hinge residues, prevents the S6 rearrangements that are necessary for closure of the activation gate. Our results reveal general similarities to, and differences from, BTX actions on eukaryotic Nav channels, whose major subunit is a single polypeptide formed by four concatenated, homologous, nonidentical domains that form a pseudosymmetric pore. Our determination of the mechanism by which BTX activates homotetrameric voltage-gated channels reveals further similarities between eukaryotic and prokaryotic Nav channels and emphasizes the tractability of bacterial Nav channels as models of voltage-dependent ion channel gating. The results contribute toward a deeper, atomic-level understanding of use-dependent natural and synthetic Nav channel agonists and antagonists, despite their overlapping binding motifs on the channel proteins.
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Affiliation(s)
- Rocio K Finol-Urdaneta
- Department of Physiology & Pharmacology and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada .,Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA.,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia
| | - Jeffrey R McArthur
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA.,Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales, Australia
| | | | - Rachelle Gaudet
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA
| | - Denis B Tikhonov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia
| | - Boris S Zhorov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia.,Department of Biological Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Robert J French
- Department of Physiology & Pharmacology and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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157
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Fux JE, Mehta A, Moffat J, Spafford JD. Eukaryotic Voltage-Gated Sodium Channels: On Their Origins, Asymmetries, Losses, Diversification and Adaptations. Front Physiol 2018; 9:1406. [PMID: 30519187 PMCID: PMC6259924 DOI: 10.3389/fphys.2018.01406] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 09/14/2018] [Indexed: 12/19/2022] Open
Abstract
The appearance of voltage-gated, sodium-selective channels with rapid gating kinetics was a limiting factor in the evolution of nervous systems. Two rounds of domain duplications generated a common 24 transmembrane segment (4 × 6 TM) template that is shared amongst voltage-gated sodium (Nav1 and Nav2) and calcium channels (Cav1, Cav2, and Cav3) and leak channel (NALCN) plus homologs from yeast, different single-cell protists (heterokont and unikont) and algae (green and brown). A shared architecture in 4 × 6 TM channels include an asymmetrical arrangement of extended extracellular L5/L6 turrets containing a 4-0-2-2 pattern of cysteines, glycosylated residues, a universally short III-IV cytoplasmic linker and often a recognizable, C-terminal PDZ binding motif. Six intron splice junctions are conserved in the first domain, including a rare U12-type of the minor spliceosome provides support for a shared heritage for sodium and calcium channels, and a separate lineage for NALCN. The asymmetrically arranged pores of 4x6 TM channels allows for a changeable ion selectivity by means of a single lysine residue change in the high field strength site of the ion selectivity filter in Domains II or III. Multicellularity and the appearance of systems was an impetus for Nav1 channels to adapt to sodium ion selectivity and fast ion gating. A non-selective, and slowly gating Nav2 channel homolog in single cell eukaryotes, predate the diversification of Nav1 channels from a basal homolog in a common ancestor to extant cnidarians to the nine vertebrate Nav1.x channel genes plus Nax. A close kinship between Nav2 and Nav1 homologs is evident in the sharing of most (twenty) intron splice junctions. Different metazoan groups have lost their Nav1 channel genes altogether, while vertebrates rapidly expanded their gene numbers. The expansion in vertebrate Nav1 channel genes fills unique functional niches and generates overlapping properties contributing to redundancies. Specific nervous system adaptations include cytoplasmic linkers with phosphorylation sites and tethered elements to protein assemblies in First Initial Segments and nodes of Ranvier. Analogous accessory beta subunit appeared alongside Nav1 channels within different animal sub-phyla. Nav1 channels contribute to pace-making as persistent or resurgent currents, the former which is widespread across animals, while the latter is a likely vertebrate adaptation.
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Affiliation(s)
- Julia E Fux
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Amrit Mehta
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - Jack Moffat
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
| | - J David Spafford
- Department of Biology, University of Waterloo, Waterloo, ON, Canada
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158
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Pan X, Li Z, Zhou Q, Shen H, Wu K, Huang X, Chen J, Zhang J, Zhu X, Lei J, Xiong W, Gong H, Xiao B, Yan N. Structure of the human voltage-gated sodium channel Na v1.4 in complex with β1. Science 2018; 362:science.aau2486. [PMID: 30190309 DOI: 10.1126/science.aau2486] [Citation(s) in RCA: 263] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/20/2018] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium (Nav) channels, which are responsible for action potential generation, are implicated in many human diseases. Despite decades of rigorous characterization, the lack of a structure of any human Nav channel has hampered mechanistic understanding. Here, we report the cryo-electron microscopy structure of the human Nav1.4-β1 complex at 3.2-Å resolution. Accurate model building was made for the pore domain, the voltage-sensing domains, and the β1 subunit, providing insight into the molecular basis for Na+ permeation and kinetic asymmetry of the four repeats. Structural analysis of reported functional residues and disease mutations corroborates an allosteric blocking mechanism for fast inactivation of Nav channels. The structure provides a path toward mechanistic investigation of Nav channels and drug discovery for Nav channelopathies.
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Affiliation(s)
- Xiaojing Pan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Medicine, Tsinghua University, Beijing 100084, China
| | - Zhangqiang Li
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiang Zhou
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,School of Medicine, Tsinghua University, Beijing 100084, China
| | - Huaizong Shen
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,School of Medicine, Tsinghua University, Beijing 100084, China
| | - Kun Wu
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaoshuang Huang
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China.,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiaofeng Chen
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Juanrong Zhang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xuechen Zhu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianlin Lei
- School of Life Sciences, Tsinghua University, Beijing 100084, China.,Technology Center for Protein Sciences, Ministry of Education Key Laboratory of Protein Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Xiong
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haipeng Gong
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China
| | - Bailong Xiao
- Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Pharmaceutical Sciences, Tsinghua University, Beijing 100084, China
| | - Nieng Yan
- State Key Laboratory of Membrane Biology, Tsinghua University, Beijing 100084, China. .,Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing 100084, China.,Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China.,School of Life Sciences, Tsinghua University, Beijing 100084, China
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