I-band fragment I65-I70 from titin

Experimental Data Snapshot

  • Resolution: 3.30 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.222 

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A regular pattern of Ig super-motifs defines segmental flexibility as the elastic mechanism of the titin chain

von Castelmur, E.Marino, M.Svergun, D.I.Kreplak, L.Ucurum-Fotiadis, Z.Konarev, P.V.Urzhumtsev, A.Labeit, D.Labeit, S.Mayans, O.

(2008) Proc Natl Acad Sci U S A 105: 1186-1191

  • DOI: https://doi.org/10.1073/pnas.0707163105
  • Primary Citation of Related Structures:  
    2RIK, 2RJM, 3B43

  • PubMed Abstract: 

    Myofibril elasticity, critical to muscle function, is dictated by the intrasarcomeric filament titin, which acts as a molecular spring. To date, the molecular events underlying the mechanics of the folded titin chain remain largely unknown. We have elucidated the crystal structure of the 6-Ig fragment I65-I70 from the elastic I-band fraction of titin and validated its conformation in solution using small angle x-ray scattering. The long-range properties of the chain have been visualized by electron microscopy on a 19-Ig fragment and modeled for the full skeletal tandem. Results show that conserved Ig-Ig transition motifs generate high-order in the structure of the filament, where conformationally stiff segments interspersed with pliant hinges form a regular pattern of dynamic super-motifs leading to segmental flexibility in the chain. Pliant hinges support molecular shape rearrangements that dominate chain behavior at moderate stretch, whereas stiffer segments predictably oppose high stretch forces upon full chain extension. There, librational entropy can be expected to act as an energy barrier to prevent Ig unfolding while, instead, triggering the unraveling of flanking springs formed by proline, glutamate, valine, and lysine (PEVK) sequences. We propose a mechanistic model based on freely jointed rigid segments that rationalizes the response to stretch of titin Ig-tandems according to molecular features.

  • Organizational Affiliation

    Division of Structural Biology, Biozentrum, University of Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Titin570Oryctolagus cuniculusMutation(s): 0 
Find proteins for D0VWS0 (Oryctolagus cuniculus)
Explore D0VWS0 
Go to UniProtKB:  D0VWS0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupD0VWS0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.30 Å
  • R-Value Free: 0.267 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.222 
  • Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 141.43α = 90
b = 141.43β = 90
c = 166.01γ = 120
Software Package:
Software NamePurpose
XSCALEdata processing
PDB_EXTRACTdata extraction
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-01-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Derived calculations, Version format compliance