Troponin-C-mediated calcium-sensitive changes in the conformation of troponin I detected by pyrene excimer fluorescence.

Conformation of Amylose in DMSO Probed by Pyrene Excimer Fluorescence

The solution structure of a cardiac troponin C-troponin I-troponin T complex shows a somewhat compact troponin C interacting with an extended troponin I-troponin T component.

We have investigated the structure of the cTnC-cTnI-cTnT(198-298) calcium-saturated, ternary cardiac troponin complex by small-angle scattering with contrast variation. Shape restoration was also applied to the scattering information resulting from the deuterated cTnC subunit, the unlabeled cTnI-cTnT(198-298) subunits, and the entire complex. The experimental results and modeling indicate that ...

Conformation of the regulatory domain of cardiac muscle troponin C in its complex with cardiac troponin I.

Calcium activation of fast striated muscle results from an opening of the regulatory N-terminal domain of fast skeletal troponin C (fsTnC), and a substantial exposure of a hydrophobic patch, essential for Ca(2+)-dependent interaction with fast skeletal troponin I (fsTnI). This interaction is obligatory to relieve the inhibition of strong, force-generating actin-myosin interactions. We have dete...

Phosphorylation of skeletal-muscle troponin I and troponin T by phospholipid-sensitive Ca2+-dependent protein kinase and its inhibition by troponin C and tropomyosin.

Skeletal-muscle troponin I and troponin T were found to be rapidly phosphorylated by cardiac phospholipid-sensitive Ca2+-dependent protein kinase, with Km values of 6.66 and 0.13 microM respectively. Stoichiometric phosphorylation of skeletal troponin I (endogenous phosphate content 0.7 mol/mol) indicated that the Ca2+-dependent enzyme and cyclic AMP-dependent protein kinase incorporated 0.9 an...

Probing Intramacromolecular Forces by Pyrene Excimer Fluorescence

INTRODUCTION Intramacromolecular forces (IMFs) of a macromolecule control its conformation and deformability under stress. For instance, shear will induce the elongation of a macromolecule only if it is subject to a stress that overcomes its IMFs. Since changes in the conformation of a macromolecule are usually associated with changes in the viscoelastic properties of its solution, the characte...