The calcitonin gene-related peptide (CGRP) receptor is a complex of a cal-citonin receptor-like receptor (CLR), which is a family B G-protein-coupled receptor (GPCR) and receptor activity modifying protein 1. The role of the second extracellular loop (ECL2) of CLR in binding CGRP and coupling to Gs was investigated using a combination of mutagenesis and modelling. An alanine scan of residues 271-294 of CLR showed that the ability of CGRP to produce cAMP was impaired by point mutations at 13 residues; most of these also impaired the response to adrenomedullin (AM). These data were used to select probable ECL2-modelled conformations that are involved in agonist binding, allowing the identification of the likely contacts between the peptide and receptor. The implications of the most likely structures for receptor activation are discussed. © 2013 The Authors.
Bibliographical note© 2013 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses by/3.0/, which permits unrestricted use, provided the original author and source are credited.
Funding: Wellcome Trust ; New Zealand Heart Foundation; MRC [G1001812]
- calcitonin gene-related peptide
- calcitonin receptor-like receptor
- class B G-protein-coupled receptor
- loop modelling
- site-directed mutagenesis