Hydrogen/Deuterium Exchange analysis of RXR-rexinoid interactions in the presence and absence of coactivator peptide GRIP-1

摘要

HD X profiles of RXR LBD + 9cUAB30/9cRA/Targretin produced distinct profiles in regions outside of the AF-2 region that are not evident in cocrystal structures. Greatest dynamic differences were observed following 2 m deuterium incubation period. HD X +/- ligand +/- Grip-1 illustrates the cooperative nature of ligand/coactivator binding and provides insight into RXR mediated transcriptional activation. Addition of Grip-1 to RXR-ligand complexes results in a overall reduction in RXR dynamics. HD X +/- 9cUAB30/9cRA +/- Grip-1 allows us to characterize unique RXR-ligand dynamics in the context of cancer related transcriptional activation. Highly toxic 9cRA vs. nontoxic 9cUAB30 show differential dynamics in Helix 11 and Helix 12 (AF-2 domain) regions only in the presence of Grip-1. Observed HD X signatures will guide in vivo studies to investigate structure-activity relationships.