Cardiac troponin I inhibitory peptide: location of interaction sites on troponin C

FEBS Lett. 2000 Mar 10;469(2-3):168-72. doi: 10.1016/s0014-5793(00)01271-0.

Abstract

Cardiac troponin I(129-149) binds to the calcium saturated cardiac troponin C/troponin I(1-80) complex at two distinct sites. Binding of the first equivalent of troponin I(129-149) was found to primarily affect amide proton chemical shifts in the regulatory domain, while the second equivalent perturbed amide proton chemical shifts within the D/E linker region. Nitrogen-15 transverse relaxation rates showed that binding the first equivalent of inhibitory peptide to the regulatory domain decreased conformational exchange in defunct calcium binding site I and that addition of the second equivalent of inhibitory peptide decreased flexibility in the D/E linker region. No interactions between the inhibitory peptide and the C-domain of cardiac troponin C were detected by these methods demonstrating that the inhibitory peptide cannot displace cTnI(1-80) from the C-domain.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Calcium / chemistry
  • Calcium / metabolism
  • Magnetic Resonance Spectroscopy
  • Mice
  • Models, Biological
  • Molecular Sequence Data
  • Myocardium / chemistry*
  • Peptide Fragments / chemistry*
  • Peptide Fragments / metabolism
  • Peptide Mapping
  • Protein Conformation
  • Protein Structure, Tertiary
  • Troponin C / chemistry*
  • Troponin C / metabolism
  • Troponin I / chemistry*
  • Troponin I / metabolism

Substances

  • Peptide Fragments
  • Troponin C
  • Troponin I
  • Calcium