Figure 7.
Spectroscopic monitoring of domain-domain interaction between the N-terminal (aa 1–600) and central (aa 2000–2500) domains in the RyR2. A, Site-directed fluorescence labeling of the RyR2 with MCA. MCA fluorescence labeling took place only when DPc10-SAED was used to mediate site-specific labeling (left lane). No MCA fluorescence was seen when DPc10-mut-SAED was used (middle lane) or when an excess concentration of DPc10 (10 mmol/L) was added during the labeling (‘cold chase’, right lane). B, Left: Stern-Volmer plots of the MCA fluorescence quenching data with QSY®7-BSA of WT mice. Right: Comparison of the Stern-Volmer plots of the MCA fluorescence quenching data of R2474S/+ KI mice with those of WT mice. Note that the KQ increased in the SR vesicles from KI to a similar level as that of DPc10-added WT SR vesicles. The values of KQ are means±SE of 5–9 experiments using 2–3 SR preparations from 20–30 mice heart. C, Summarized data of KQ shown in Figures 7B.