Figure 2. The hBRM BRD splice variants have the same overall fold but different thermal stability.

(a) Overlay of ¹H-¹⁵N HSQC spectra of ¹⁵N-hBRM-A (black) and ¹⁵N-hBRM-B (green) BRDs. Resonances corresponding to the extra 18-aa in hBRM-A are labelled (*). (b) CD data collected on the two splice variants of the hBRM BRD. CD spectra collected at 19 °C on the hBRM-A (black) and hBRM-B (green) BRDs confirm an α-helical structure for both splice variants (left). Thermal denaturation curves are plotted as the raw ellipticity measured at 222 nm as a function of temperature and show that the hBRM-A BRD curve (black) is shifted by ∼20 °C from the hBRM-B BRD curve (green) (right). The thermal denaturation curves were fit to the Gibbs–Helmholtz equation for unfolding as a function of temperature (solid lines), and the fit values along with the error in the fit for the melting temperatures (T_M) are shown.