Probing CBD-A/B interactions in apo, C-bound, and cAMP₂-bound RIα (91–379) through CBD-B deletion.

Abstract

<p><b>(A)</b> Overlay of the HN-TROSY spectra of C-bound RIα (91–379) and RIα (91–244), in which CBD-B is deleted. <b>(B)</b> Correlation between the combined chemical shifts (CCS) of C-bound RIα (91–379) and RIα (91–244). <b>(C, D)</b> As in panels (A, B), but for the apo forms of RIα (91–379) and RIα (91–244). <b>(E, F)</b> As in panels (A, B), but for the cAMP₂-bound form of RIα (91–379) and the cAMP-bound form of RIα (91–244). Color codes for panels A, C, and E are indicated in the figure and representative CBD-A and -B cross-peaks are labeled. <b>(G)</b> Map of above-average RIα (91–379):cAMP₂ versus RIα (91–244):cAMP CCS differences for residues <226 (blue spheres) onto the structure of RIα (91–379):cAMP₂ (PDB Code: 1RGS). <b>(H)</b> Cyan spheres represent CBD-A residues experiencing solvent accessible surface area (SASA) changes upon deletion of residues 226–379, which are highlighted with a grey surface. This SASA map was built using the same structure as in panel (G).</p