6KN8

Structure of human cardiac thin filament in the calcium bound state


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 4.80 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Cardiac muscle thin filament structures reveal calcium regulatory mechanism.

Yamada, Y.Namba, K.Fujii, T.

(2020) Nat Commun 11: 153-153

  • DOI: https://doi.org/10.1038/s41467-019-14008-1
  • Primary Citation of Related Structures:  
    6KN7, 6KN8

  • PubMed Abstract: 

    Contraction of striated muscles is driven by cyclic interactions of myosin head projecting from the thick filament with actin filament and is regulated by Ca 2+ released from sarcoplasmic reticulum. Muscle thin filament consists of actin, tropomyosin and troponin, and Ca 2+ binding to troponin triggers conformational changes of troponin and tropomyosin to allow actin-myosin interactions. However, the structural changes involved in this regulatory mechanism remain unknown. Here we report the structures of human cardiac muscle thin filament in the absence and presence of Ca 2+ by electron cryomicroscopy. Molecular models in the two states built based on available crystal structures reveal the structures of a C-terminal region of troponin I and an N-terminal region of troponin T in complex with the head-to-tail junction of tropomyosin together with the troponin core on actin filament. Structural changes of the thin filament upon Ca 2+ binding now reveal the mechanism of Ca 2+ regulation of muscle contraction.


  • Organizational Affiliation

    Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Actin, alpha skeletal muscle
A, B, C, D, E
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O
375Oryctolagus cuniculusMutation(s): 0 
EC: 3.6.4
UniProt
Find proteins for P68135 (Oryctolagus cuniculus)
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Go to UniProtKB:  P68135
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP68135
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Tropomyosin alpha-1 chain
P, Q, W, X
274Homo sapiensMutation(s): 0 
Gene Names: TPM1C15orf13TMSA
UniProt & NIH Common Fund Data Resources
Find proteins for P09493 (Homo sapiens)
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PHAROS:  P09493
GTEx:  ENSG00000140416 
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Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP09493
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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Tropomyosin alpha-1 chain
R, S, Y, Z
31Homo sapiensMutation(s): 0 
Gene Names: TPM1C15orf13TMSA
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GTEx:  ENSG00000140416 
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UniProt GroupP09493
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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
Troponin T, cardiac muscleAA [auth a],
T
174Homo sapiensMutation(s): 0 
Gene Names: TNNT2
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Find proteins for P45379 (Homo sapiens)
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PHAROS:  P45379
GTEx:  ENSG00000118194 
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Entity ID: 5
MoleculeChains Sequence LengthOrganismDetailsImage
Troponin I, cardiac muscleBA [auth b],
U
126Homo sapiensMutation(s): 0 
Gene Names: TNNI3TNNC1
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Find proteins for P19429 (Homo sapiens)
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PHAROS:  P19429
GTEx:  ENSG00000129991 
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Entity ID: 6
MoleculeChains Sequence LengthOrganismDetailsImage
Troponin C, slow skeletal and cardiac musclesCA [auth c],
V
160Homo sapiensMutation(s): 0 
Gene Names: TNNC1TNNC
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Find proteins for P63316 (Homo sapiens)
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PHAROS:  P63316
GTEx:  ENSG00000114854 
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UniProt GroupP63316
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Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
ADP
Query on ADP

Download Ideal Coordinates CCD File 
DA [auth A]
EA [auth B]
FA [auth C]
GA [auth D]
HA [auth E]
DA [auth A],
EA [auth B],
FA [auth C],
GA [auth D],
HA [auth E],
IA [auth F],
JA [auth G],
KA [auth H],
LA [auth I],
MA [auth J],
NA [auth K],
OA [auth L],
PA [auth M],
QA [auth N],
RA [auth O]
ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 4.80 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2020-01-15
    Type: Initial release
  • Version 1.1: 2020-01-22
    Changes: Database references
  • Version 1.2: 2024-03-27
    Changes: Data collection, Database references