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- EMDB-48476: Structure of native murine cardiac thin filament variant I79N in ... -
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Basic information
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Title | Structure of native murine cardiac thin filament variant I79N in troponin T at pCa=5.8 in Ca2+-free state (lower strand) | |||||||||
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![]() | thin filament / cryo-EM / troponin / tropomyosin / muscle structure / motor protein | |||||||||
Function / homology | ![]() actin-mediated cell contraction / positive regulation of heart rate by epinephrine / muscle thin filament tropomyosin / RHOB GTPase cycle / Formation of the dystrophin-glycoprotein complex (DGC) / regulation of systemic arterial blood pressure by ischemic conditions / Striated Muscle Contraction / troponin C binding / diaphragm contraction / RHOA GTPase cycle ...actin-mediated cell contraction / positive regulation of heart rate by epinephrine / muscle thin filament tropomyosin / RHOB GTPase cycle / Formation of the dystrophin-glycoprotein complex (DGC) / regulation of systemic arterial blood pressure by ischemic conditions / Striated Muscle Contraction / troponin C binding / diaphragm contraction / RHOA GTPase cycle / regulation of ATP-dependent activity / regulation of muscle filament sliding speed / troponin T binding / Smooth Muscle Contraction / cardiac Troponin complex / cardiac myofibril / troponin complex / actin-myosin filament sliding / regulation of muscle contraction / cardiac myofibril assembly / regulation of smooth muscle contraction / negative regulation of ATP-dependent activity / positive regulation of ATP-dependent activity / transition between fast and slow fiber / Ion homeostasis / cardiac muscle tissue morphogenesis / actomyosin structure organization / Striated Muscle Contraction / muscle filament sliding / response to metal ion / I band / regulation of cardiac muscle contraction by calcium ion signaling / ventricular cardiac muscle tissue morphogenesis / microfilament motor activity / myosin binding / regulation of heart contraction / tropomyosin binding / troponin I binding / myofibril / mesenchyme migration / striated muscle thin filament / skeletal muscle thin filament assembly / striated muscle contraction / vasculogenesis / calcium channel inhibitor activity / cardiac muscle contraction / sarcomere / filopodium / actin filament / structural constituent of cytoskeleton / Hydrolases; Acting on acid anhydrides; Acting on acid anhydrides to facilitate cellular and subcellular movement / intracellular calcium ion homeostasis / response to calcium ion / calcium-dependent protein binding / actin filament binding / lamellipodium / actin cytoskeleton / actin binding / heart development / cell body / response to ethanol / in utero embryonic development / hydrolase activity / response to xenobiotic stimulus / protein heterodimerization activity / protein domain specific binding / synapse / calcium ion binding / positive regulation of gene expression / negative regulation of apoptotic process / protein kinase binding / glutamatergic synapse / protein homodimerization activity / ATP binding / identical protein binding / cytosol / cytoplasm Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 5.2 Å | |||||||||
![]() | Risi CM / Galkin VE | |||||||||
Funding support | ![]()
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![]() | ![]() Title: The role of the troponin T interactions with actin in regulation of cardiac thin filament revealed by the troponin T pathogenic variant Ile79Asn. Authors: Cristina M Risi / Maicon Landim-Vieira / Betty Belknap / P Bryant Chase / Jose R Pinto / Vitold E Galkin / ![]() Abstract: Cardiac muscle contraction/relaxation cycle depends on the rising and falling Ca levels in sarcomeres that control the extent of interactions between myosin-based thick and actin-based thin filaments. ...Cardiac muscle contraction/relaxation cycle depends on the rising and falling Ca levels in sarcomeres that control the extent of interactions between myosin-based thick and actin-based thin filaments. Cardiac thin filament (cTF) consists of actin, tropomyosin (Tm) that regulates myosin binding to actin, and troponin complex that governs Tm position upon Ca-binding. Troponin has three subunits - Ca-binding troponin C (TnC), Tm stabilizing troponin T (TnT), and inhibitory troponin I (TnI). TnT N-terminus (TnT1) interactions with actin stabilize the inhibited state of cTF. TnC, TnI, and Tm work in concert to control actomyosin interactions. Cryo-electron microscopy (cryo-EM) provided factual structures of healthy cTF, but structures of cTF carrying missense mutations linked to human cardiomyopathy are unknown. Variant Ile79Asn in human cardiac TnT (TnT-I79N) increases myofilament Ca sensitivity and slows cross-bridge kinetics, leading to severe hypertrophic/restrictive cardiomyopathy. Here, we used TnT-I79N mutation as a tool to examine the role of TnT1 in the complex mechanism of cTF regulation. Comparison of the cryo-EM structures of murine wild type and TnT-I79N native cTFs at systolic Ca levels (pCa = 5.8) demonstrates that TnT-I79N causes 1) dissociation of the TnT1 loop from its actin interface that results in Tm release to a more activated position, 2) reduced interaction of TnI C-terminus with actin-Tm, and 3) increased frequency of Ca-bound regulatory units. Our data indicate that the TnT1 loop is a crucial element of the allosteric regulatory network that couples Tn subunits and Tm to maintain adequate cTF response to physiological Ca levels during a heartbeat. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 8.8 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 24.8 KB 24.8 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 11.5 KB | Display | ![]() |
Images | ![]() | 30.5 KB | ||
Filedesc metadata | ![]() | 7.2 KB | ||
Others | ![]() ![]() | 102.1 MB 102.1 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Validation report
Summary document | ![]() | 754.5 KB | Display | ![]() |
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Full document | ![]() | 754 KB | Display | |
Data in XML | ![]() | 19.2 KB | Display | |
Data in CIF | ![]() | 25.3 KB | Display | |
Arichive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 9mooMC ![]() 9e2eC ![]() 9mo4C ![]() 9mo5C ![]() 9mo6C ![]() 9mo7C ![]() 9mo8C ![]() 9mo9C ![]() 9moaC ![]() 9mobC ![]() 9mocC ![]() 9modC ![]() 9moiC ![]() 9mokC ![]() 9molC ![]() 9momC ![]() 9monC ![]() 9mopC ![]() 9mouC ![]() 9mowC ![]() 9moxC M: atomic model generated by this map 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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Projections & slices | Image control
Images are generated by Spider. | ||||||||||||||||||||||||||||||||||||
Voxel size | X=Y=Z: 1.356 Å | ||||||||||||||||||||||||||||||||||||
Density |
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Symmetry | Space group: 1 | ||||||||||||||||||||||||||||||||||||
Details | EMDB XML:
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-Supplemental data
-Half map: #2
File | emd_48476_half_map_1.map | ||||||||||||
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Projections & Slices |
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Density Histograms |
-Half map: #1
File | emd_48476_half_map_2.map | ||||||||||||
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Density Histograms |
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Sample components
-Entire : Native murine cardiac thin filament variant I79N in troponin T at...
Entire | Name: Native murine cardiac thin filament variant I79N in troponin T at pCa=5.8 |
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Components |
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-Supramolecule #1: Native murine cardiac thin filament variant I79N in troponin T at...
Supramolecule | Name: Native murine cardiac thin filament variant I79N in troponin T at pCa=5.8 type: complex / ID: 1 / Parent: 0 / Macromolecule list: #1-#5 |
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Source (natural) | Organism: ![]() ![]() |
-Macromolecule #1: Actin, alpha cardiac muscle 1
Macromolecule | Name: Actin, alpha cardiac muscle 1 / type: protein_or_peptide / ID: 1 / Number of copies: 6 / Enantiomer: LEVO EC number: Hydrolases; Acting on acid anhydrides; Acting on acid anhydrides to facilitate cellular and subcellular movement |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 42.064891 KDa |
Sequence | String: MCDDEETTAL VCDNGSGLVK AGFAGDDAPR AVFPSIVGRP RHQGVMVGMG QKDSYVGDEA QSKRGILTLK YPIEHGIITN WDDMEKIWH HTFYNELRVA PEEHPTLLTE APLNPKANRE KMTQIMFETF NVPAMYVAIQ AVLSLYASGR TTGIVLDSGD G VTHNVPIY ...String: MCDDEETTAL VCDNGSGLVK AGFAGDDAPR AVFPSIVGRP RHQGVMVGMG QKDSYVGDEA QSKRGILTLK YPIEHGIITN WDDMEKIWH HTFYNELRVA PEEHPTLLTE APLNPKANRE KMTQIMFETF NVPAMYVAIQ AVLSLYASGR TTGIVLDSGD G VTHNVPIY EGYALPHAIM RLDLAGRDLT DYLMKILTER GYSFVTTAER EIVRDIKEKL CYVALDFENE MATAASSSSL EK SYELPDG QVITIGNERF RCPETLFQPS FIGMESAGIH ETTYNSIMKC DIDIRKDLYA NNVLSGGTTM YPGIADRMQK EIT ALAPST MKIKIIAPPE RKYSVWIGGS ILASLSTFQQ MWISKQEYDE AGPSIVHRKC F UniProtKB: Actin, alpha cardiac muscle 1 |
-Macromolecule #2: Troponin C, slow skeletal and cardiac muscles
Macromolecule | Name: Troponin C, slow skeletal and cardiac muscles / type: protein_or_peptide / ID: 2 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 18.43752 KDa |
Sequence | String: MDDIYKAAVE QLTEEQKNEF KAAFDIFVLG AEDGCISTKE LGKVMRMLGQ NPTPEELQEM IDEVDEDGSG TVDFDEFLVM MVRCMKDDS KGKSEEELSD LFRMFDKNAD GYIDLDELKM MLQATGETIT EDDIEELMKD GDKNNDGRID YDEFLEFMKG V E UniProtKB: Troponin C, slow skeletal and cardiac muscles |
-Macromolecule #3: Troponin I, cardiac muscle
Macromolecule | Name: Troponin I, cardiac muscle / type: protein_or_peptide / ID: 3 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 24.308908 KDa |
Sequence | String: MADESSDAAG EPQPAPAPVR RRSSANYRAY ATEPHAKKKS KISASRKLQL KTLMLQIAKQ EMEREAEERR GEKGRVLRTR CQPLELDGL GFEELQDLCR QLHARVDKVD EERYDVEAKV TKNITEIADL TQKIYDLRGK FKRPTLRRVR ISADAMMQAL L GTRAKESL ...String: MADESSDAAG EPQPAPAPVR RRSSANYRAY ATEPHAKKKS KISASRKLQL KTLMLQIAKQ EMEREAEERR GEKGRVLRTR CQPLELDGL GFEELQDLCR QLHARVDKVD EERYDVEAKV TKNITEIADL TQKIYDLRGK FKRPTLRRVR ISADAMMQAL L GTRAKESL DLRAHLKQVK KEDIEKENRE VGDWRKNIDA LSGMEGRKKK FEG UniProtKB: Troponin I, cardiac muscle |
-Macromolecule #4: Isoform 6 of Troponin T, cardiac muscle
Macromolecule | Name: Isoform 6 of Troponin T, cardiac muscle / type: protein_or_peptide / ID: 4 / Number of copies: 2 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 34.660332 KDa |
Sequence | String: MSDIEEVVEE YEEEEQEEAA VEEQEEAAEE DAEAEAETEE TRAEEDEEEE EAKEAEDGPM EESKPKPRSF MPNLVPPKNP DGERVDFDD IHRKRMEKDL NELQALIEAH FENRKKEEEE LVSLKDRIER RRAERAEQQR IRNEREKERQ NRLAEERARR E EEENRRKA ...String: MSDIEEVVEE YEEEEQEEAA VEEQEEAAEE DAEAEAETEE TRAEEDEEEE EAKEAEDGPM EESKPKPRSF MPNLVPPKNP DGERVDFDD IHRKRMEKDL NELQALIEAH FENRKKEEEE LVSLKDRIER RRAERAEQQR IRNEREKERQ NRLAEERARR E EEENRRKA EDEARKKKAL SNMMHFGGYI QKQAQTERKS GKRQTEREKK KKILAERRKV LAIDHLNEDQ LREKAKELWQ SI YNLEAEK FDLQEKFKQQ KYEINVLRNR INDNQKVSKT RGKAKVTGRW K UniProtKB: Troponin T, cardiac muscle |
-Macromolecule #5: Tropomyosin alpha-1 chain
Macromolecule | Name: Tropomyosin alpha-1 chain / type: protein_or_peptide / ID: 5 / Number of copies: 4 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 32.735609 KDa |
Sequence | String: MDAIKKKMQM LKLDKENALD RAEQAEADKK AAEDRSKQLE DELVSLQKKL KGTEDELDKY SEALKDAQEK LELAEKKATD AEADVASLN RRIQLVEEEL DRAQERLATA LQKLEEAEKA ADESERGMKV IESRAQKDEE KMEIQEIQLK EAKHIAEDAD R KYEEVARK ...String: MDAIKKKMQM LKLDKENALD RAEQAEADKK AAEDRSKQLE DELVSLQKKL KGTEDELDKY SEALKDAQEK LELAEKKATD AEADVASLN RRIQLVEEEL DRAQERLATA LQKLEEAEKA ADESERGMKV IESRAQKDEE KMEIQEIQLK EAKHIAEDAD R KYEEVARK LVIIESDLER AEERAELSEG KCAELEEELK TVTNNLKSLE AQAEKYSQKE DKYEEEIKVL SDKLKEAETR AE FAERSVT KLEKSIDDLE DELYAQKLKY KAISEELDHA LNDMTSI UniProtKB: Tropomyosin alpha-1 chain |
-Macromolecule #6: ADENOSINE-5'-DIPHOSPHATE
Macromolecule | Name: ADENOSINE-5'-DIPHOSPHATE / type: ligand / ID: 6 / Number of copies: 6 / Formula: ADP |
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Molecular weight | Theoretical: 427.201 Da |
Chemical component information | ![]() ChemComp-ADP: |
-Macromolecule #7: MAGNESIUM ION
Macromolecule | Name: MAGNESIUM ION / type: ligand / ID: 7 / Number of copies: 6 / Formula: MG |
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Molecular weight | Theoretical: 24.305 Da |
-Experimental details
-Structure determination
Method | cryo EM |
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![]() | single particle reconstruction |
Aggregation state | filament |
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Sample preparation
Buffer | pH: 7 |
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Grid | Model: EMS Lacey Carbon / Material: COPPER / Mesh: 300 / Pretreatment - Type: GLOW DISCHARGE / Pretreatment - Time: 45 sec. |
Vitrification | Cryogen name: ETHANE |
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Electron microscopy
Microscope | TFS KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Number real images: 17361 / Average electron dose: 34.0 e/Å2 |
Electron beam | Acceleration voltage: 300 kV / Electron source: ![]() |
Electron optics | Illumination mode: FLOOD BEAM / Imaging mode: BRIGHT FIELD / Nominal defocus max: 3.5 µm / Nominal defocus min: 0.5 µm |
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 |
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Refinement | Space: REAL / Protocol: FLEXIBLE FIT | ||||||||||
Output model | ![]() PDB-9moo: |