1J1D

Crystal structure of the 46kDa domain of human cardiac troponin in the Ca2+ saturated form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.264 

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This is version 1.3 of the entry. See complete history


Literature

Structure of the core domain of human cardiac troponin in the Ca2+-saturated form

Takeda, S.Yamashita, A.Maeda, K.Maeda, Y.

(2003) Nature 424: 35-41

  • DOI: https://doi.org/10.1038/nature01780
  • Primary Citation of Related Structures:  
    1J1D, 1J1E

  • PubMed Abstract: 
  • Troponin is essential in Ca(2+) regulation of skeletal and cardiac muscle contraction. It consists of three subunits (TnT, TnC and TnI) and, together with tropomyosin, is located on the actin filament. Here we present crystal structures of the core domains (relative molecular mass of 46,000 and 52,000) of human cardiac troponin in the Ca(2+)-saturated form ...

    Troponin is essential in Ca(2+) regulation of skeletal and cardiac muscle contraction. It consists of three subunits (TnT, TnC and TnI) and, together with tropomyosin, is located on the actin filament. Here we present crystal structures of the core domains (relative molecular mass of 46,000 and 52,000) of human cardiac troponin in the Ca(2+)-saturated form. Analysis of the four-molecule structures reveals that the core domain is further divided into structurally distinct subdomains that are connected by flexible linkers, making the entire molecule highly flexible. The alpha-helical coiled-coil formed between TnT and TnI is integrated in a rigid and asymmetric structure (about 80 angstrom long), the IT arm, which bridges putative tropomyosin-anchoring regions. The structures of the troponin ternary complex imply that Ca(2+) binding to the regulatory site of TnC removes the carboxy-terminal portion of TnI from actin, thereby altering the mobility and/or flexibility of troponin and tropomyosin on the actin filament.


    Related Citations: 
    • Structural and functional domains of the troponin complex revealed by limited digestion
      Takeda, S., Kobayashi, T., Taniguchi, H., Hayashi, H., Maeda, Y.
      (1997) Eur J Biochem 246: 611
    • Crystal structure of troponin C in complex with troponin I fragment at 2.3-A resolution
      Vassylyev, D.G., Takeda, S., Wakatsuki, S., Maeda, K., Maeda, Y.
      (1998) Proc Natl Acad Sci U S A 95: 4847

    Organizational Affiliation

    Laboratory for Structural Biochemistry, RIKEN Harima Institute at SPring-8, Mikazuki, Sayo, Hyogo, Japan. stakeda@ri.ncvc.go.jp



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin CA, D161Homo sapiensMutation(s): 2 
Gene Names: TNNC1TNNC
UniProt & NIH Common Fund Data Resources
Find proteins for P63316 (Homo sapiens)
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Go to UniProtKB:  P63316
PHAROS:  P63316
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UniProt GroupP63316
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin TB, E106Homo sapiensMutation(s): 0 
Gene Names: TNNT2
UniProt & NIH Common Fund Data Resources
Find proteins for P45379 (Homo sapiens)
Explore P45379 
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PHAROS:  P45379
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UniProt GroupP45379
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin IC, F133Homo sapiensMutation(s): 3 
Gene Names: TNNI3TNNC1
UniProt & NIH Common Fund Data Resources
Find proteins for P19429 (Homo sapiens)
Explore P19429 
Go to UniProtKB:  P19429
PHAROS:  P19429
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UniProt GroupP19429
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.61 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.264 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.346α = 90
b = 167.86β = 101.35
c = 69.707γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
SHARPphasing
CNSrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-07-15
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-10
    Changes: Database references, Derived calculations