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- EMDB-42858: The structure of the native cardiac thin filament troponin core i... -
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Open data
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Basic information
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Title | The structure of the native cardiac thin filament troponin core in Ca2+-bound partially activated state from the lower strand | |||||||||
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![]() | thin filament / troponin / tropomyosin / cryo-EM / muscle structure / MOTOR PROTEIN | |||||||||
Function / homology | ![]() Striated Muscle Contraction / cardiac Troponin complex / actin-myosin filament sliding / troponin complex / regulation of muscle contraction / myosin binding / heart contraction / mesenchyme migration / troponin I binding / skeletal muscle contraction ...Striated Muscle Contraction / cardiac Troponin complex / actin-myosin filament sliding / troponin complex / regulation of muscle contraction / myosin binding / heart contraction / mesenchyme migration / troponin I binding / skeletal muscle contraction / cardiac muscle contraction / sarcomere / filopodium / actin filament organization / actin filament / actin filament binding / calcium-dependent protein binding / actin cytoskeleton / lamellipodium / actin binding / cell body / protein heterodimerization activity / calcium ion binding / positive regulation of gene expression / protein homodimerization activity / identical protein binding / cytoplasm Similarity search - Function | |||||||||
Biological species | ![]() ![]() | |||||||||
Method | single particle reconstruction / cryo EM / Resolution: 5.2 Å | |||||||||
![]() | Galkin VE / Risi CM | |||||||||
Funding support | ![]()
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![]() | ![]() Title: Troponin Structural Dynamics in the Native Cardiac Thin Filament Revealed by Cryo Electron Microscopy. Authors: Cristina M Risi / Betty Belknap / Jennifer Atherton / Isabella Leite Coscarella / Howard D White / P Bryant Chase / Jose R Pinto / Vitold E Galkin / ![]() Abstract: Cardiac muscle contraction occurs due to repetitive interactions between myosin thick and actin thin filaments (TF) regulated by Ca levels, active cross-bridges, and cardiac myosin-binding protein C ...Cardiac muscle contraction occurs due to repetitive interactions between myosin thick and actin thin filaments (TF) regulated by Ca levels, active cross-bridges, and cardiac myosin-binding protein C (cMyBP-C). The cardiac TF (cTF) has two nonequivalent strands, each comprised of actin, tropomyosin (Tm), and troponin (Tn). Tn shifts Tm away from myosin-binding sites on actin at elevated Ca levels to allow formation of force-producing actomyosin cross-bridges. The Tn complex is comprised of three distinct polypeptides - Ca-binding TnC, inhibitory TnI, and Tm-binding TnT. The molecular mechanism of their collective action is unresolved due to lack of comprehensive structural information on Tn region of cTF. C1 domain of cMyBP-C activates cTF in the absence of Ca to the same extent as rigor myosin. Here we used cryo-EM of native cTFs to show that cTF Tn core adopts multiple structural conformations at high and low Ca levels and that the two strands are structurally distinct. At high Ca levels, cTF is not entirely activated by Ca but exists in either partially or fully activated state. Complete dissociation of TnI C-terminus is required for full activation. In presence of cMyBP-C C1 domain, Tn core adopts a fully activated conformation, even in absence of Ca. Our data provide a structural description for the requirement of myosin to fully activate cTFs and explain increased affinity of TnC to Ca in presence of active cross-bridges. We suggest that allosteric coupling between Tn subunits and Tm is required to control actomyosin interactions. | |||||||||
History |
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Structure visualization
Supplemental images |
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Downloads & links
-EMDB archive
Map data | ![]() | 2.3 MB | ![]() | |
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Header (meta data) | ![]() ![]() | 22.5 KB 22.5 KB | Display Display | ![]() |
FSC (resolution estimation) | ![]() | 11.5 KB | Display | ![]() |
Images | ![]() | 88.8 KB | ||
Filedesc metadata | ![]() | 6.7 KB | ||
Others | ![]() ![]() | 102.3 MB 102.4 MB | ||
Archive directory | ![]() ![]() | HTTPS FTP |
-Related structure data
Related structure data | ![]() 8v0kMC ![]() 8uwwC ![]() 8uwxC ![]() 8uwyC ![]() 8uydC ![]() 8uz5C ![]() 8uz6C ![]() 8uzxC ![]() 8uzyC ![]() 8v01C ![]() 8v0iC ![]() 8v0yC 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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Annotation | map | ||||||||||||||||||||
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: half1
File | emd_42858_half_map_1.map | ||||||||||||
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Annotation | half1 | ||||||||||||
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Density Histograms |
-Half map: half2
File | emd_42858_half_map_2.map | ||||||||||||
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Annotation | half2 | ||||||||||||
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Density Histograms |
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Sample components
-Entire : thin filament troponin core complex
Entire | Name: thin filament troponin core complex |
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Components |
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-Supramolecule #1: thin filament troponin core complex
Supramolecule | Name: thin filament troponin core complex / 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: 2 / Enantiomer: LEVO |
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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: 18.433508 KDa |
Sequence | String: MDDIYKAAVE QLTEEQKNEF KAAFDIFVLG AEDGCISTKE LGKVMRMLGQ NPTPEELQEM IDEVDEDGSG TVDFDEFLVM MVRCMKDDS KGKSEEELSD LFRMFDKNAD GYIDLEELKI 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: 24.09268 KDa |
Sequence | String: MADRSGDAAG DSRPAPAPVR RRSSANYRAY ATEPHAKKKS KISASRKLQL KTLMLQIAKQ ELEREAEERR GEKGRALSTR CQPLELAGL SFAELQDLCR QLHARVDKVD EERYDVEAKV TKNITEIADL NQKIFDLRGK FKRPTLRRVR ISADAMMQAL L GARAKETL ...String: MADRSGDAAG DSRPAPAPVR RRSSANYRAY ATEPHAKKKS KISASRKLQL KTLMLQIAKQ ELEREAEERR GEKGRALSTR CQPLELAGL SFAELQDLCR QLHARVDKVD EERYDVEAKV TKNITEIADL NQKIFDLRGK FKRPTLRRVR ISADAMMQAL L GARAKETL DLRAHLKQVK KEDTEKENRE VGDWRKNIDA LSGMEGRKKK FEG UniProtKB: Troponin I, cardiac muscle |
-Macromolecule #4: Troponin T2, cardiac type
Macromolecule | Name: Troponin T2, cardiac type / type: protein_or_peptide / ID: 4 / Number of copies: 1 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 33.941738 KDa |
Sequence | String: MSDVEETVDE YEEEQEEGAA EEQEEAVEEE AGGEAEAEEA NAEEAGQEED GREAEDGPME ESKPKPRLFM PNLVPPKIPD GERVDFDDI HRKRMKDLNE LQTLIEAHFE NRKKEEELVS LKDRIEKRRA ERAEQQRIRT EREKERQTRL AEERARREEE E NRRKAEDE ...String: MSDVEETVDE YEEEQEEGAA EEQEEAVEEE AGGEAEAEEA NAEEAGQEED GREAEDGPME ESKPKPRLFM PNLVPPKIPD GERVDFDDI HRKRMKDLNE LQTLIEAHFE NRKKEEELVS LKDRIEKRRA ERAEQQRIRT EREKERQTRL AEERARREEE E NRRKAEDE ARKKKALSNM MHFGGYIQKQ AQTERKSGKR QTEREKKKKI LAERRKVLAI DHLNEDQLRE KAKELWQSIY NL EAEKFDL QEKFKQQKYE INVLRNRIND NQKVSKTRGK AKVTGRWK 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: 2 / Enantiomer: LEVO |
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Source (natural) | Organism: ![]() ![]() |
Molecular weight | Theoretical: 32.762656 KDa |
Sequence | String: MDAIKKKMQM LKLDKENALD RAEQAEADKK AAEDRSKRLE DELVSLQKKL KATEDELDKY SEAPKDAQEK LELAEKKATD AEADVASLN RRIQLVEEEL DRAQERLATA LQKLEEAEKA ADESERGMKV IESRAQKDEE KMEIQEIQLK EAKHIAEDAD R KYEEVARK ...String: MDAIKKKMQM LKLDKENALD RAEQAEADKK AAEDRSKRLE DELVSLQKKL KATEDELDKY SEAPKDAQEK 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: 2 / 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: 2 / Formula: MG |
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Molecular weight | Theoretical: 24.305 Da |
-Macromolecule #8: CALCIUM ION
Macromolecule | Name: CALCIUM ION / type: ligand / ID: 8 / Number of copies: 3 / Formula: CA |
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Molecular weight | Theoretical: 40.078 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: 7.2 |
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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 / Chamber humidity: 100 % / Chamber temperature: 278 K |
Details | non-helical filament |
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Electron microscopy
Microscope | FEI TITAN KRIOS |
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Image recording | Film or detector model: GATAN K3 (6k x 4k) / Number real images: 24179 / 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-8v0k: |