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- EMDB-41629: Cryo-EM structure of the human MRS2 magnesium channel under Mg2+ ... -
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Open data
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Basic information
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Title | Cryo-EM structure of the human MRS2 magnesium channel under Mg2+ condition (C1 map) | |||||||||
![]() | local resolution filtered map | |||||||||
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![]() | Magnesium / Ion channel / Membrane protein / METAL TRANSPORT / Ion Translocation / Divalent Ion / Mg2+ / Pentamer | |||||||||
Function / homology | mitochondrial magnesium ion transmembrane transport / Magnesium transporter MRS2-like / Miscellaneous transport and binding events / magnesium ion transmembrane transporter activity / lactate metabolic process / transmembrane transport / mitochondrial inner membrane / mitochondrion / Magnesium transporter MRS2 homolog, mitochondrial![]() | |||||||||
Biological species | ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 3.1 Å | |||||||||
![]() | Lai LTF / Balaraman J / Zhou F / Matthies D | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Cryo-EM structures of human magnesium channel MRS2 reveal gating and regulatory mechanisms. Authors: Louis Tung Faat Lai / Jayashree Balaraman / Fei Zhou / Doreen Matthies / ![]() Abstract: Magnesium ions (Mg) play an essential role in cellular physiology. In mitochondria, protein and ATP synthesis and various metabolic pathways are directly regulated by Mg. MRS2, a magnesium channel ...Magnesium ions (Mg) play an essential role in cellular physiology. In mitochondria, protein and ATP synthesis and various metabolic pathways are directly regulated by Mg. MRS2, a magnesium channel located in the inner mitochondrial membrane, mediates the influx of Mg into the mitochondrial matrix and regulates Mg homeostasis. Knockdown of MRS2 in human cells leads to reduced uptake of Mg into mitochondria and disruption of the mitochondrial metabolism. Despite the importance of MRS2, the Mg translocation and regulation mechanisms of MRS2 are still unclear. Here, using cryo-EM we report the structures of human MRS2 in the presence and absence of Mg at 2.8 Å and 3.3 Å, respectively. From the homo-pentameric structures, we identify R332 and M336 as major gating residues, which are then tested using mutagenesis and two cellular divalent ion uptake assays. A network of hydrogen bonds is found connecting the gating residue R332 to the soluble domain, potentially regulating the gate. Two Mg-binding sites are identified in the MRS2 soluble domain, distinct from the two sites previously reported in CorA, a homolog of MRS2 in prokaryotes. Altogether, this study provides the molecular basis for understanding the Mg translocation and regulatory mechanisms of MRS2. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 4.8 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 27.1 KB 27.1 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 10.6 KB | Display | ![]() |
Images | ![]() | 77.1 KB | ||
Masks | ![]() | 125 MB | ![]() | |
Filedesc metadata | ![]() | 7 KB | ||
Others | ![]() ![]() ![]() ![]() | 62.3 MB 118 MB 116 MB 116 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8tulC ![]() 8tupC C: citing same article ( |
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Similar structure data | Similarity search - Function & homology ![]() |
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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 | local resolution filtered map | ||||||||||||||||||||
Voxel size | X=Y=Z: 0.83 Å | ||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Mask #1
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-Additional map: unsharpened map
File | emd_41629_additional_1.map | ||||||||||||
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Annotation | unsharpened map | ||||||||||||
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-Additional map: sharpened map
File | emd_41629_additional_2.map | ||||||||||||
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Annotation | sharpened map | ||||||||||||
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-Half map: half map B
File | emd_41629_half_map_1.map | ||||||||||||
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Annotation | half map B | ||||||||||||
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-Half map: half map A
File | emd_41629_half_map_2.map | ||||||||||||
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Annotation | half map A | ||||||||||||
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Sample components
-Entire : Cryo-EM structure of the pentameric human MRS2 magnesium channel ...
Entire | Name: Cryo-EM structure of the pentameric human MRS2 magnesium channel under Mg2+ condition at an average resolution of 2.8 A, filtered to local resolution, C1 |
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Components |
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-Supramolecule #1: Cryo-EM structure of the pentameric human MRS2 magnesium channel ...
Supramolecule | Name: Cryo-EM structure of the pentameric human MRS2 magnesium channel under Mg2+ condition at an average resolution of 2.8 A, filtered to local resolution, C1 type: complex / ID: 1 / Parent: 0 / Macromolecule list: all |
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Source (natural) | Organism: ![]() |
Molecular weight | Theoretical: 219 KDa |
-Macromolecule #1: Mitochondrial RNA Splicing 2
Macromolecule | Name: Mitochondrial RNA Splicing 2 / type: protein_or_peptide / ID: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() |
Recombinant expression | Organism: ![]() |
Sequence | String: MECLRSLPCL LPRAMRLPRR TLCALALDVT SVGPPVAACG RRANLIGRSR AAQLCGPDRL RVAGEVHRFR TSDVSQATLA SVAPVFTVT KFDKQGNVTS FERKKTELYQ ELGLQARDLR FQHVMSITVR NNRIIMRMEY LKAVITPECL LILDYRNLNL E QWLFRELP ...String: MECLRSLPCL LPRAMRLPRR TLCALALDVT SVGPPVAACG RRANLIGRSR AAQLCGPDRL RVAGEVHRFR TSDVSQATLA SVAPVFTVT KFDKQGNVTS FERKKTELYQ ELGLQARDLR FQHVMSITVR NNRIIMRMEY LKAVITPECL LILDYRNLNL E QWLFRELP SQLSGEGQLV TYPLPFEFRA IEALLQYWIN TLQGKLSILQ PLILETLDAL VDPKHSSVDR SKLHILLQNG KS LSELETD IKIFKESILE ILDEEELLEE LCVSKWSDPQ VFEKSSAGID HAEEMELLLE NYYRLADDLS NAARELRVLI DDS QSIIFI NLDSHRNVMM RLNLQLTMGT FSLSLFGLMG VAFGMNLESS LEEDHRIFWL ITGIMFMGSG LIWRRLLSFL GRQL EAPLP PMMASLPKKT LLADRSMELK NSLRLDGLGS GRSILTNRDY KDDDDK UniProtKB: Magnesium transporter MRS2 homolog, mitochondrial |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | particle |
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Sample preparation
Concentration | 0.5 mg/mL | ||||||||||
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Buffer | pH: 7.3 Component:
Details: 20 mM HEPES, 150 mM NaCl, 40 mM MgCl2, 0.003% LMNG, pH 7.3 | ||||||||||
Grid | Model: Quantifoil R1.2/1.3 / Material: COPPER / Mesh: 400 / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 60 sec. / Pretreatment - Atmosphere: AIR | ||||||||||
Vitrification | Cryogen name: ETHANE / Chamber humidity: 95 % / Chamber temperature: 277 K / Instrument: LEICA EM GP Details: 400-mesh R1.2/1.3 Cu grids (Quantifoil) were made hydrophilic by glow discharging for 60 seconds with a current of 15 mA in a PELCO easiGlow system. The cryo grids were produced using a ...Details: 400-mesh R1.2/1.3 Cu grids (Quantifoil) were made hydrophilic by glow discharging for 60 seconds with a current of 15 mA in a PELCO easiGlow system. The cryo grids were produced using a Leica EM GP2 (Leica). The chamber was kept at 4 C and set to 95% humidity. 3 microliter sample at 0.5 mg/ml was applied to a glow-discharged holey grid, blotted for 6 s, and plunge frozen into liquid ethane and stored in liquid nitrogen.. | ||||||||||
Details | This sample was monodisperse |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Specialist optics | Energy filter - Name: GIF Bioquantum / Energy filter - Slit width: 20 eV Details: Cryo-EM datasets were acquired with SerialEM using a Titan Krios (FEI, now ThermoFisher Scientific) operated at 300 keV and equipped with an energy filter and K3 camera (Gatan Inc.). Movies ...Details: Cryo-EM datasets were acquired with SerialEM using a Titan Krios (FEI, now ThermoFisher Scientific) operated at 300 keV and equipped with an energy filter and K3 camera (Gatan Inc.). Movies of 50 frames with a dose of 1 e-/A2 per frame (50 e-/A2 total dose) were recorded at a nominal magnification of 105,000x, corresponding to a physical pixel size of 0.83 A/px (super-resolution pixel size 0.415 A/px) in CDS mode at a dose rate of 10 e-/px/s and a defocus range of -0.7 to -2.0 um. In total, 3,991 and 9,656 movies were collected. |
Image recording | Film or detector model: GATAN K3 BIOQUANTUM (6k x 4k) / Number grids imaged: 1 / Number real images: 3991 / Average exposure time: 3.462 sec. / Average electron dose: 50.0 e/Å2 Details: Cryo-EM datasets were acquired with SerialEM using a Titan Krios (FEI, now ThermoFisher Scientific) operated at 300 keV and equipped with an energy filter and K3 camera (Gatan Inc.). Movies ...Details: Cryo-EM datasets were acquired with SerialEM using a Titan Krios (FEI, now ThermoFisher Scientific) operated at 300 keV and equipped with an energy filter and K3 camera (Gatan Inc.). Movies of 50 frames with a dose of 1 e-/A2 per frame (50 e-/A2 total dose) were recorded at a nominal magnification of 105,000x, corresponding to a physical pixel size of 0.83 A/px (super-resolution pixel size 0.415 A/px) in CDS mode at a dose rate of 10 e-/px/s and a defocus range of -0.7 to -2.0 um. In total, 3,991 and 9,656 movies were collected. |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | C2 aperture diameter: 100.0 µm / Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Cs: 2.7 mm / Nominal defocus max: 2.0 µm / Nominal defocus min: 0.7000000000000001 µm / Nominal magnification: 105000 |
Sample stage | Specimen holder model: FEI TITAN KRIOS AUTOGRID HOLDER / Cooling holder cryogen: NITROGEN |
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Image processing
-Atomic model buiding 1
Initial model | PDB ID: Chain - Source name: AlphaFold / Chain - Initial model type: in silico model |
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Details | The model was then manually rebuilt in COOT v.0.9.7 using the local resolution filtered map, which was generated from refinement with C5 applied. The Mg2+ ions assigned in the pore regions were confirmed in the C1 map. Loop regions (residues 174-181, 273-287) were built with the unsharpened map. Iterative rounds of manual refinement in COOT and real-space refinement in Phenix v.1.20.1-4487 were performed. |
Refinement | Space: REAL / Protocol: FLEXIBLE FIT / Overall B value: 141 |