Figure 5.

C-domain residues of WT and D145E isoforms differ in stability, as measured by NMR cross-peak intensities between 15° and 55 °C. (a,b) Changes in resonance intensities of the C-domain as a function of temperature, normalized to values at 15 °C. Green residue intensities are unperturbed or increased by temperature changes and classified as non-decaying group (NDG). Red residues lose intensity and are classified as decaying group (DG). In Black is the biphasic decaying group (“mountain-like”, ML-DG) for D145E. (c) Bottom view of the mutant cTnC C-domain, highlighting in black and red the residues identified respectively as ML-DG and DG in panel (b). Calcium ions are shown as green spheres. Truncated curves in (a) and (b) represent peaks that were lost due to line broadening or overlap at higher temperatures.