2jm4
From Proteopedia
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The solution NMR structure of the relaxin (RXFP1) receptor LDLa module.
Overview
The receptors for the peptide hormones relaxin and insulin-like peptide 3, (INSL3) are the leucine-rich repeat-containing G-protein-coupled receptors, LGR7 and LGR8 recently renamed as the relaxin family peptide (RXFP), receptors, RXFP1 and RXFP2, respectively. These receptors differ from, other LGRs by the addition of an N-terminal low density lipoprotein, receptor class A (LDLa) module and are the only human G-protein-coupled, receptors to contain such a domain. Recently it was shown that the LDLa, module of the RXFP1 and RXFP2 receptors is essential for ligand-stimulated, cAMP signaling. The mechanism by which the LDLa module modulates receptor, signaling is unknown; however, it represents a unique paradigm in, understanding G-protein-coupled receptor signaling. Here we present the, structure of the RXFP1 receptor LDLa module determined by solution NMR, spectroscopy. The structure is similar to other LDLa modules but shows, small differences in side chain orientations and inter-residue packing., Interchange of the module with the second ligand binding domain of the LDL, receptor, LB2, results in a receptor that binds relaxin with full affinity, but is unable to signal. Furthermore, we demonstrate via structural, studies on mutated LDLa modules and functional studies on mutated, full-length receptors that a hydrophobic surface within the N-terminal, region of the module is essential for activation of RXFP1 receptor signal, in response to relaxin stimulation. This study has highlighted the, necessity to understand the structural effects of single amino acid, mutations on the LDLa module to fully interpret the effects of these, mutations on receptor activity.
About this Structure
2JM4 is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.
Reference
The NMR solution structure of the relaxin (RXFP1) receptor lipoprotein receptor class A module and identification of key residues in the N-terminal region of the module that mediate receptor activation., Hopkins EJ, Layfield S, Ferraro T, Bathgate RA, Gooley PR, J Biol Chem. 2007 Feb 9;282(6):4172-84. Epub 2006 Dec 4. PMID:17148455
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