Refolding and characterization of a soluble ectodomain complex of the calcitonin gene-related peptide receptor.
Biochemistry
; 49(9): 1862-72, 2010 Mar 09.
Article
em En
| MEDLINE
| ID: mdl-20099900
ABSTRACT
The calcitonin gene-related peptide (CGRP) receptor is a heterodimer of two membrane proteins calcitonin receptor-like receptor (CLR) and receptor activity-modifying protein 1 (RAMP1). CLR is a class B G-protein-coupled receptor (GPCR), possessing a characteristic large amino-terminal extracellular domain (ECD) important for ligand recognition and binding. Dimerization of CLR with RAMP1 provides specificity for CGRP versus related agonists. Here we report the expression, purification, and refolding of a soluble form of the CGRP receptor comprising a heterodimer of the CLR and RAMP1 ECDs. The extracellular protein domains corresponding to residues 23-133 of CLR and residues 26-117 of RAMP1 were shown to be sufficient for formation of a stable, monodisperse complex. The binding affinity of the purified ECD complex for the CGRP peptide was significantly lower than that of the native receptor (IC(50) of 12 microM for the purified ECD complex vs 233 pM for membrane-bound CGRP receptor), indicating that other regions of CLR and/or RAMP1 are important for peptide agonist binding. However, high-affinity binding to known potent and specific nonpeptide antagonists of the CGRP receptor, including olcegepant and telcagepant (K(D) < 0.02 muM), as well as N-terminally truncated peptides and peptide analogues (140 nM to 1.62 microM) was observed.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Dobramento de Proteína
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Receptores de Peptídeo Relacionado com o Gene de Calcitonina
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Receptores da Calcitonina
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Espaço Extracelular
Limite:
Humans
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article