Interaction of a fragment of the cannabinoid CB1 receptor C-terminus with arrestin-2

Desensitization of the cannabinoid CBI receptor is mediated by the interaction with arrestin. In this study, we report the structural changes of a synthetic diphosphorylated peptide corresponding to residues 419-439 of the CBI C-terminus upon binding to arrestin-2. This segment is pivotal to the desensitization of CBI. Using high-resolution proton NMR, we observe two helical segments in the bound peptide that are separated by the presence a glycine residue. The binding we observe is with a diphoshorylated peptide, whereas a previous study reported binding of a highly phosphorylated rhodopsin fragment to visual arrestin. The arrestin bound conformations of the peptides are compared. (c) 2007 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.