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 

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This is version 1.1 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: 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 ...

    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: 

    JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan. tfujii@fbs.osaka-u.ac.jp.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Actin, alpha skeletal muscle
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O
375Oryctolagus cuniculusMutation(s): 0 
Gene Names: ACTA1, ACTA
UniProt
Find proteins for P68135 (Oryctolagus cuniculus)
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Go to UniProtKB:  P68135
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UniProt GroupP68135
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Tropomyosin alpha-1 chainP, Q, W, X274Homo sapiensMutation(s): 0 
Gene Names: TPM1, C15orf13, TMSA
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PHAROS:  P09493
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UniProt GroupP09493
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
Tropomyosin alpha-1 chainR, S, Y, Z31Homo sapiensMutation(s): 0 
Gene Names: TPM1, C15orf13, TMSA
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Entity ID: 4
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin T, cardiac muscleT,
AA [auth a]		174Homo sapiensMutation(s): 0 
Gene Names: TNNT2
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Entity ID: 5
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin I, cardiac muscleU,
BA [auth b]		126Homo sapiensMutation(s): 0 
Gene Names: TNNI3, TNNC1
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Entity ID: 6
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin C, slow skeletal and cardiac musclesV,
CA [auth c]		160Homo sapiensMutation(s): 0 
Gene Names: TNNC1, TNNC
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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