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Open data
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Basic information
Entry | Database: EMDB / ID: EMD-22898 | |||||||||
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Title | Cryo-EM structure of SARS-CoV-2 ORF3a | |||||||||
![]() | Sharpened and locally filtered map | |||||||||
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![]() | SARS-CoV-2 / coronavirus / transport protein / viral protein / viroporin / membrane protein | |||||||||
Function / homology | ![]() host cell lysosome / induction by virus of host reticulophagy / Maturation of protein 3a / Defective ABCA1 causes TGD / Scavenging by Class B Receptors / HDL clearance / high-density lipoprotein particle receptor binding / spherical high-density lipoprotein particle / positive regulation of hydrolase activity / SARS-CoV-2 modulates autophagy ...host cell lysosome / induction by virus of host reticulophagy / Maturation of protein 3a / Defective ABCA1 causes TGD / Scavenging by Class B Receptors / HDL clearance / high-density lipoprotein particle receptor binding / spherical high-density lipoprotein particle / positive regulation of hydrolase activity / SARS-CoV-2 modulates autophagy / negative regulation of response to cytokine stimulus / regulation of intestinal cholesterol absorption / protein oxidation / vitamin transport / cholesterol import / high-density lipoprotein particle binding / ABC transporters in lipid homeostasis / blood vessel endothelial cell migration / negative regulation of heterotypic cell-cell adhesion / apolipoprotein receptor binding / apolipoprotein A-I receptor binding / negative regulation of cytokine production involved in immune response / negative regulation of cell adhesion molecule production / HDL assembly / negative regulation of very-low-density lipoprotein particle remodeling / peptidyl-methionine modification / phosphatidylcholine biosynthetic process / glucocorticoid metabolic process / acylglycerol homeostasis / Chylomicron remodeling / phosphatidylcholine-sterol O-acyltransferase activator activity / positive regulation of phospholipid efflux / Chylomicron assembly / positive regulation of cholesterol metabolic process / lipid storage / high-density lipoprotein particle clearance / phospholipid homeostasis / chylomicron / high-density lipoprotein particle remodeling / phospholipid efflux / chemorepellent activity / cholesterol transfer activity / reverse cholesterol transport / very-low-density lipoprotein particle / high-density lipoprotein particle assembly / low-density lipoprotein particle / positive regulation of CoA-transferase activity / lipoprotein biosynthetic process / cholesterol transport / high-density lipoprotein particle / regulation of Cdc42 protein signal transduction / triglyceride homeostasis / inorganic cation transmembrane transport / HDL remodeling / endothelial cell proliferation / negative regulation of interleukin-1 beta production / Scavenging by Class A Receptors / cholesterol efflux / voltage-gated calcium channel complex / host cell endoplasmic reticulum / negative chemotaxis / positive regulation of cholesterol efflux / positive regulation of Rho protein signal transduction / adrenal gland development / cholesterol binding / cholesterol biosynthetic process / endocytic vesicle / negative regulation of tumor necrosis factor-mediated signaling pathway / SARS-CoV-2 targets host intracellular signalling and regulatory pathways / Scavenging of heme from plasma / Retinoid metabolism and transport / positive regulation of substrate adhesion-dependent cell spreading / positive regulation of phagocytosis / voltage-gated potassium channel complex / positive regulation of stress fiber assembly / endocytic vesicle lumen / heat shock protein binding / cholesterol metabolic process / cholesterol homeostasis / molecular function activator activity / integrin-mediated signaling pathway / Post-translational protein phosphorylation / PPARA activates gene expression / regulation of protein phosphorylation / negative regulation of inflammatory response / Heme signaling / cytoplasmic side of plasma membrane / phospholipid binding / Regulation of Insulin-like Growth Factor (IGF) transport and uptake by Insulin-like Growth Factor Binding Proteins (IGFBPs) / extracellular vesicle / Platelet degranulation / protein complex oligomerization / monoatomic ion channel activity / amyloid-beta binding / host cell endosome / cytoplasmic vesicle / secretory granule lumen / collagen-containing extracellular matrix / Translation of Structural Proteins / Virion Assembly and Release Similarity search - Function | |||||||||
Biological species | ![]() ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 2.08 Å | |||||||||
![]() | Kern DM / Hoel CM | |||||||||
Funding support | ![]()
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![]() | Journal: bioRxiv / Year: 2021 Title: Cryo-EM structure of the SARS-CoV-2 3a ion channel in lipid nanodiscs. Authors: David M Kern / Ben Sorum / Sonali S Mali / Christopher M Hoel / Savitha Sridharan / Jonathan P Remis / Daniel B Toso / Abhay Kotecha / Diana M Bautista / Stephen G Brohawn / ![]() ![]() Abstract: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes the coronavirus disease 2019 (COVID-19). SARS-CoV-2 encodes three putative ion channels: E, 8a, and 3a. 3a is ...Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus that causes the coronavirus disease 2019 (COVID-19). SARS-CoV-2 encodes three putative ion channels: E, 8a, and 3a. 3a is expressed in SARS patient tissue and anti-3a antibodies are observed in patient plasma. 3a has been implicated in viral release, inhibition of autophagy, inflammasome activation, and cell death and its deletion reduces viral titer and morbidity in mice, raising the possibility that 3a could be an effective vaccine or therapeutic target. Here, we present the first cryo-EM structures of SARS-CoV-2 3a to 2.1 Å resolution and demonstrate 3a forms an ion channel in reconstituted liposomes. The structures in lipid nanodiscs reveal 3a dimers and tetramers adopt a novel fold with a large polar cavity that spans halfway across the membrane and is accessible to the cytosol and the surrounding bilayer through separate water- and lipid-filled openings. Electrophysiology and fluorescent ion imaging experiments show 3a forms Ca-permeable non-selective cation channels. We identify point mutations that alter ion permeability and discover polycationic inhibitors of 3a channel activity. We find 3a-like proteins in multiple and lineages that infect bats and humans. These data show 3a forms a functional ion channel that may promote COVID-19 pathogenesis and suggest targeting 3a could broadly treat coronavirus diseases. | |||||||||
History |
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Structure visualization
Movie |
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Structure viewer | EM map: ![]() ![]() ![]() |
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 3.2 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 21.1 KB 21.1 KB | Display Display | ![]() |
Images | ![]() | 152.7 KB | ||
Filedesc metadata | ![]() | 6.2 KB | ||
Others | ![]() ![]() ![]() | 5.7 MB 95.6 MB 95.6 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 7kjrMC ![]() 6xdcC C: citing same article ( M: atomic model generated by this map |
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Similar structure data | |
EM raw data | ![]() Data size: 3.2 TB Data #1: Unaligned movies in EER format of SARS-CoV-2 3a in MSP1E3D1 lipid nanodiscs - 1379 frames [micrographs - multiframe] Data #2: Unaligned movies in EER format of SARS-CoV-2 3a in MSP1E3D1 lipid nanodiscs - 1449 frames [micrographs - multiframe]) |
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Links
EMDB pages | ![]() ![]() |
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Related items in Molecule of the Month |
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Map
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Annotation | Sharpened and locally filtered map | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 0.727 Å | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
CCP4 map header:
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-Supplemental data
-Additional map: Density modified map
File | emd_22898_additional_1.map | ||||||||||||
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Annotation | Density modified map | ||||||||||||
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Density Histograms |
-Half map: Half map 2
File | emd_22898_half_map_1.map | ||||||||||||
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Annotation | Half map 2 | ||||||||||||
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Density Histograms |
-Half map: Half map 1
File | emd_22898_half_map_2.map | ||||||||||||
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Annotation | Half map 1 | ||||||||||||
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Density Histograms |
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Sample components
-Entire : SARS-CoV-2 protein 3A in lipid nanodiscs
Entire | Name: SARS-CoV-2 protein 3A in lipid nanodiscs |
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Components |
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-Supramolecule #1: SARS-CoV-2 protein 3A in lipid nanodiscs
Supramolecule | Name: SARS-CoV-2 protein 3A in lipid nanodiscs / type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#2 |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 62 KDa |
-Macromolecule #1: ORF3a protein
Macromolecule | Name: ORF3a protein / type: protein_or_peptide / ID: 1 / Number of copies: 2 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 32.165902 KDa |
Recombinant expression | Organism: ![]() ![]() |
Sequence | String: MDLFMRIFTI GTVTLKQGEI KDATPSDFVR ATATIPIQAS LPFGWLIVGV ALLAVFQSAS KIITLKKRWQ LALSKGVHFV CNLLLLFVT VYSHLLLVAA GLEAPFLYLY ALVYFLQSIN FVRIIMRLWL CWKCRSKNPL LYDANYFLCW HTNCYDYCIP Y NSVTSSIV ...String: MDLFMRIFTI GTVTLKQGEI KDATPSDFVR ATATIPIQAS LPFGWLIVGV ALLAVFQSAS KIITLKKRWQ LALSKGVHFV CNLLLLFVT VYSHLLLVAA GLEAPFLYLY ALVYFLQSIN FVRIIMRLWL CWKCRSKNPL LYDANYFLCW HTNCYDYCIP Y NSVTSSIV ITSGDGTTSP ISEHDYQIGG YTEKWESGVK DCVVLHSYFT SDYYQLYSTQ LSTDTGVEHV TFFIYNKIVD EP EEHVQIH TIDGSSGVVN PVMEPIYDEP TTTTSVPLSN SLEVLFQ UniProtKB: ORF3a protein |
-Macromolecule #2: Apolipoprotein A-I
Macromolecule | Name: Apolipoprotein A-I / type: protein_or_peptide / ID: 2 / Number of copies: 2 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 24.647678 KDa |
Recombinant expression | Organism: ![]() ![]() |
Sequence | String: HHHHHHHDYD IPTTENLYFQ GSTFSKLREQ LGPVTQEFWD NLEKETEGLR QEMSKDLEEV KAKVQPYLDD FQKKWQEEME LYRQKVEPL RAELQEGARQ KLHELQEKLS PLGEEMRDRA RAHVDALRTH LAPYSDELRQ RLAARLEALK ENGGARLAEY H AKATEHLS ...String: HHHHHHHDYD IPTTENLYFQ GSTFSKLREQ LGPVTQEFWD NLEKETEGLR QEMSKDLEEV KAKVQPYLDD FQKKWQEEME LYRQKVEPL RAELQEGARQ KLHELQEKLS PLGEEMRDRA RAHVDALRTH LAPYSDELRQ RLAARLEALK ENGGARLAEY H AKATEHLS TLSEKAKPAL EDLRQGLLPV LESFKVSFLS ALEEYTKKLN TQ UniProtKB: Apolipoprotein A-I |
-Macromolecule #3: 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine
Macromolecule | Name: 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine / type: ligand / ID: 3 / Number of copies: 2 / Formula: PEE |
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Molecular weight | Theoretical: 744.034 Da |
Chemical component information | ![]() ChemComp-PEE: |
-Macromolecule #4: water
Macromolecule | Name: water / type: ligand / ID: 4 / Number of copies: 122 / Formula: HOH |
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Molecular weight | Theoretical: 18.015 Da |
Chemical component information | ![]() ChemComp-HOH: |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Concentration | 1.1 mg/mL | |||||||||
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Buffer | pH: 7.4 Component:
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Grid | Model: Quantifoil R1.2/1.3 / Material: GOLD / Mesh: 300 / Support film - Material: CARBON / Support film - topology: HOLEY / Pretreatment - Type: GLOW DISCHARGE | |||||||||
Vitrification | Cryogen name: ETHANE / Chamber humidity: 100 % / Chamber temperature: 277 K / Instrument: FEI VITROBOT MARK IV Details: 1 blot force 5 second wait time 3 second blot time. |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: FEI FALCON IV (4k x 4k) / Average electron dose: 50.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
Startup model | Type of model: OTHER / Details: Ab initio model |
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Final reconstruction | Number classes used: 1 / Resolution.type: BY AUTHOR / Resolution: 2.08 Å / Resolution method: FSC 0.143 CUT-OFF / Number images used: 91218 |
Initial angle assignment | Type: MAXIMUM LIKELIHOOD |
Final angle assignment | Type: MAXIMUM LIKELIHOOD |
-Atomic model buiding 1
Refinement | Space: REAL |
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Output model | ![]() PDB-7kjr: |