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Open data
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Basic information
Entry | Database: PDB / ID: 8kcw | ||||||||||||
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Title | Cryo-EM structure of human SIDT1 bound to cholesterol | ||||||||||||
![]() | SID1 transmembrane family member 1 | ||||||||||||
![]() | MEMBRANE PROTEIN | ||||||||||||
Function / homology | ![]() RNA transmembrane transporter activity / RNA transport / cholesterol binding / double-stranded RNA binding / lysosome / plasma membrane Similarity search - Function | ||||||||||||
Biological species | ![]() | ||||||||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 2.77 Å | ||||||||||||
![]() | Hirano, Y. / Ohto, U. / Shimizu, T. | ||||||||||||
Funding support | ![]()
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![]() | ![]() Title: Cryo-EM analysis reveals human SID-1 transmembrane family member 1 dynamics underlying lipid hydrolytic activity. Authors: Yoshinori Hirano / Umeharu Ohto / Ikuyo Ichi / Ryota Sato / Kensuke Miyake / Toshiyuki Shimizu / ![]() Abstract: Two mammalian homologs of systemic RNA interference defective protein 1 (SID-1) (SIDT1/2) are suggested to function as double-stranded RNA (dsRNA) transporters for extracellular dsRNA uptake or for ...Two mammalian homologs of systemic RNA interference defective protein 1 (SID-1) (SIDT1/2) are suggested to function as double-stranded RNA (dsRNA) transporters for extracellular dsRNA uptake or for release of incorporated dsRNA from lysosome to cytoplasm. SIDT1/2 is also suggested to be involved in cholesterol transport and lipid metabolism. Here, we determine the cryo-electron microscopy structures of human SIDT1, homodimer in a side-by-side arrangement, with two distinct conformations, the cholesterol-bound form and the unbound form. Our structures reveal that the membrane-spanning region of SIDT1 harbors conserved histidine and aspartate residues coordinating to putative zinc ion, in a structurally similar manner to alkaline ceramidases or adiponectin receptors that require zinc for ceramidase activity. We identify that SIDT1 has a ceramidase activity that is attenuated by cholesterol binding. Observations from two structures suggest that cholesterol molecules serve as allosteric regulator that binds the transmembrane region of SIDT1 and induces the conformation change and the reorientation of the catalytic residues. This study represents a contribution to the elucidation of the cholesterol-mediated mechanisms of lipid hydrolytic activity and RNA transport in the SID-1 family proteins. | ||||||||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 272.4 KB | Display | ![]() |
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PDB format | ![]() | 215.6 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Summary document | ![]() | 1.7 MB | Display | ![]() |
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Full document | ![]() | 1.7 MB | Display | |
Data in XML | ![]() | 42.8 KB | Display | |
Data in CIF | ![]() | 63.1 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 37112MC ![]() 8kcxC M: map data used to model this data C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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1 |
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Components
#1: Protein | Mass: 96877.312 Da / Num. of mol.: 2 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() #2: Polysaccharide | beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta- ...beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose Source method: isolated from a genetically manipulated source #3: Polysaccharide | 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose Source method: isolated from a genetically manipulated source #4: Chemical | #5: Chemical | ChemComp-CLR / Has ligand of interest | Y | |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: homo-dimer of SIDT1 / Type: COMPLEX / Entity ID: #1 / Source: RECOMBINANT |
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Molecular weight | Units: MEGADALTONS / Experimental value: NO |
Source (natural) | Organism: ![]() |
Source (recombinant) | Organism: ![]() |
Buffer solution | pH: 6 |
Specimen | Conc.: 5 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES |
Vitrification | Cryogen name: ETHANE |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 1600 nm / Nominal defocus min: 800 nm |
Image recording | Electron dose: 65.7 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) |
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Processing
CTF correction | Type: NONE |
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3D reconstruction | Resolution: 2.77 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 59745 / Symmetry type: POINT |
Refinement | Cross valid method: NONE |