1KQL

Crystal structure of the C-terminal region of striated muscle alpha-tropomyosin at 2.7 angstrom resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.252 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

The crystal structure of the C-terminal fragment of striated-muscle alpha-tropomyosin reveals a key troponin T recognition site.

Li, Y.Mui, S.Brown, J.H.Strand, J.Reshetnikova, L.Tobacman, L.S.Cohen, C.

(2002) Proc.Natl.Acad.Sci.USA 99: 7378-7383

  • DOI: 10.1073/pnas.102179999

  • PubMed Abstract: 
  • Contraction in striated and cardiac muscles is regulated by the motions of a Ca(2+)-sensitive tropomyosin/troponin switch. In contrast, troponin is absent in other muscle types and in nonmuscle cells, and actomyosin regulation is myosin-linked. Here ...

    Contraction in striated and cardiac muscles is regulated by the motions of a Ca(2+)-sensitive tropomyosin/troponin switch. In contrast, troponin is absent in other muscle types and in nonmuscle cells, and actomyosin regulation is myosin-linked. Here we report an unusual crystal structure at 2.7 A of the C-terminal 31 residues of rat striated-muscle alpha-tropomyosin (preceded by a fragment of the GCN4 leucine zipper). The C-terminal 22 residues (263-284) of the structure do not form a two-stranded alpha-helical coiled coil as does the rest of the molecule, but here the alpha-helices splay apart and are stabilized by the formation of a tail-to-tail dimer with a symmetry-related molecule. The site of splaying involves a small group of destabilizing core residues that is present only in striated muscle tropomyosin isoforms. These results reveal a specific recognition site for troponin T and clarify the physical basis for the unique regulatory mechanism of striated muscles.


    Organizational Affiliation

    Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Fusion Protein of and striated muscle alpha-tropomyosin and the GCN4 leucine zipper
A, B
56Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Rattus norvegicus
This entity is chimeric
Mutation(s): 0 
Gene Names: GCN4 (AAS3, ARG9), Tpm1 (Alpha-tm, Tpma)
Find proteins for P03069 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to UniProtKB:  P03069
Find proteins for P04692 (Rattus norvegicus)
Go to UniProtKB:  P04692
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.252 
  • Space Group: P 64 2 2
Unit Cell:
Length (Å)Angle (°)
a = 137.202α = 90.00
b = 137.202β = 90.00
c = 40.071γ = 120.00
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
AMoREphasing
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-05-29
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-07-26
    Type: Refinement description, Source and taxonomy