A molecular map of titin/connectin elasticity reveals two different mechanisms acting in series

FEBS Lett. 1996 Apr 29;385(1-2):11-4. doi: 10.1016/0014-5793(96)00338-9.


In the I-band of skeletal muscle sarcomeres, the elastic region of titin consists of immunoglobulin (Ig) domains, and non-modular regions rich in proline, hydrophobic, and charged residues (PEVK). Using immunoelectron microscopy with sequence-assigned monoclonal antibodies, we demonstrate that extension of the Ig regions in M. psoas occurs largely at sarcomere lengths between 2 and 2.8 micron, decreasing in slope towards higher lengths. The Ig domains do not unfold. Above 2.6 micron, length changes are increasingly due to the PEVK-rich regions. We therefore propose that rubber-like properties of the PEVK-rich regions are mainly contributing to skeletal titin elasticity.

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / chemistry
  • Animals
  • Antibodies, Monoclonal
  • Connectin
  • Elasticity
  • Epitope Mapping / methods
  • Immunoglobulins / chemistry
  • Molecular Sequence Data
  • Muscle Proteins / chemistry*
  • Protein Folding
  • Protein Kinases / chemistry*
  • Protein Structure, Tertiary*
  • Psoas Muscles
  • Rabbits
  • Sarcomeres / chemistry*
  • Sarcomeres / ultrastructure


  • Amino Acids
  • Antibodies, Monoclonal
  • Connectin
  • Immunoglobulins
  • Muscle Proteins
  • Protein Kinases

Associated data

  • GENBANK/X90569