3TZ1

Crystal structure of the Ca2+-saturated C-terminal domain of Akazara scallop troponin C in complex with a troponin I fragment


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.205 

wwPDB Validation   3D Report Full Report


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Literature

Structure of the Ca2+-saturated C-terminal domain of scallop troponin C in complex with a troponin I fragment

Kato, Y.S.Yumoto, F.Tanaka, H.Miyakawa, T.Miyauchi, Y.Takeshita, D.Sawano, Y.Ojima, T.Ohtsuki, I.Tanokura, M.

(2012) Biol Chem 394: 55-68

  • DOI: 10.1515/hsz-2012-0152
  • Primary Citation of Related Structures:  
    3TZ1

  • PubMed Abstract: 
  • Troponin C (TnC) is the Ca(2+)-sensing subunit of troponin that triggers the contraction of striated muscles. In scallops, the striated muscles consume little ATP energy in sustaining strong contractile forces. The N-terminal domain of TnC works as the Ca(2+) sensor in vertebrates, whereas scallop TnC uses the C-terminal domain as the Ca(2+) sensor, suggesting that there are differences in the mechanism of the Ca(2+)-dependent regulation of muscles between invertebrates and vertebrates ...

    Troponin C (TnC) is the Ca(2+)-sensing subunit of troponin that triggers the contraction of striated muscles. In scallops, the striated muscles consume little ATP energy in sustaining strong contractile forces. The N-terminal domain of TnC works as the Ca(2+) sensor in vertebrates, whereas scallop TnC uses the C-terminal domain as the Ca(2+) sensor, suggesting that there are differences in the mechanism of the Ca(2+)-dependent regulation of muscles between invertebrates and vertebrates. Here, we report the crystal structure of Akazara scallop (Chlamys nipponensis akazara) adductor muscle TnC C-terminal domain (asTnCC) complexed with a short troponin I fragment (asTnIS) and Ca(2+). The electron density of a Ca(2+) ion is observed in only one of the two EF-hands. The EF-hands of asTnCC can only be in the fully open conformation with the assistance of asTnIS. The number of hydrogen bonds between asTnCC and asTnIS is markedly lower than the number in the vertebrate counterparts. The Ca(2+) modulation on the binding between asTnCC and asTnIS is weaker, but structural change of the complex depending on Ca(2+) concentration was observed. Together, these findings provide a detailed description of the distinct molecular mechanism of contractile regulation in the scallop adductor muscle from that of vertebrates.


    Organizational Affiliation

    Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin CA74Chlamys nipponensis akazaraMutation(s): 0 
Gene Names: Troponin C
Find proteins for Q27428 (Chlamys nipponensis akazara)
Explore Q27428 
Go to UniProtKB:  Q27428
Protein Feature View
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  • Reference Sequence
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Troponin IB24Chlamys nipponensis akazaraMutation(s): 0 
Find proteins for Q7M3Y3 (Chlamys nipponensis akazara)
Explore Q7M3Y3 
Go to UniProtKB:  Q7M3Y3
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download Ideal Coordinates CCD File 
C [auth A]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.205 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 32.13α = 90
b = 42.151β = 90
c = 59.966γ = 90
Software Package:
Software NamePurpose
SOLVEphasing
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-01-23
    Type: Initial release