Structure of tropomyosin's mid-region: bending and binding sites for actin

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.256 

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Structure of the mid-region of tropomyosin: Bending and binding sites for actin.

Brown, J.H.Zhou, Z.Reshetnikova, L.Robinson, H.Yammani, R.D.Tobacman, L.S.Cohen, C.

(2005) Proc Natl Acad Sci U S A 102: 18878-18883

  • DOI: https://doi.org/10.1073/pnas.0509269102
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Tropomyosin is a two-chain alpha-helical coiled coil whose periodic interactions with the F-actin helix are critical for thin filament stabilization and the regulation of muscle contraction. Here we deduce the mechanical and chemical basis of these interactions from the 2.3-A-resolution crystal structure of the middle three of tropomyosin's seven periods. Geometrically specific bends of the coiled coil, produced by clusters of core alanines, and variable bends about gaps in the core, produced by isolated alanines, occur along the molecule. The crystal packing is notable in signifying that the functionally important fifth period includes an especially favorable protein-binding site, comprising an unusual apolar patch on the surface together with surrounding charged residues. Based on these and other results, we have constructed a specific model of the thin filament, with the N-terminal halves of each period (i.e., the so-called "alpha zones") of tropomyosin axially aligned with subdomain 3 of each monomer in F-actin.

  • Organizational Affiliation

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

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
striated-muscle alpha tropomyosin
A, B
147Rattus norvegicusMutation(s): 0 
Find proteins for P04692 (Rattus norvegicus)
Explore P04692 
Go to UniProtKB:  P04692
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04692
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.256 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 80.515α = 90
b = 80.515β = 90
c = 112.453γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-01-03
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Refinement description
  • Version 1.4: 2022-12-21
    Changes: Database references