6D1U

Crystal structure of the human CLR:RAMP1 extracellular domain heterodimer in complex with adrenomedullin 2/intermedin

Summary for 6D1U

• Entry DOI: 10.2210/pdb6d1u/pdb
• Related: 4rwf 4rwg 5v6y
• Related PRD ID: PRD_900001
• Descriptor: Maltose-binding periplasmic protein,Receptor activity-modifying protein 1,Calcitonin gene-related peptide type 1 receptor, ADM2, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, ... (5 entities in total)
• Functional Keywords: cgrp receptor, class b gpcr, peptide hormone, amidated peptide, peptide binding protein
• Biological source: Escherichia coli O157:H7; More
• Total number of polymer chains: 6
• Total formula weight: 205807.54

Authors

Pioszak, A.,Roehrkasse, A. (deposition date: 2018-04-12, release date: 2018-09-05, Last modification date: 2024-11-06)

Primary citation

Roehrkasse, A.M.,Booe, J.M.,Lee, S.M.,Warner, M.L.,Pioszak, A.A.
Structure-function analyses reveal a triple beta-turn receptor-bound conformation of adrenomedullin 2/intermedin and enable peptide antagonist design.
J. Biol. Chem., 293:15840-15854, 2018

PubMed Abstract: The cardioprotective vasodilator peptide adrenomedullin 2/intermedin (AM2/IMD) and the related adrenomedullin (AM) and calcitonin gene-related peptide (CGRP) signal through three heterodimeric receptors comprising the calcitonin receptor-like class B G protein-coupled receptor (CLR) and a variable receptor activity-modifying protein (RAMP1, -2, or -3) that determines ligand selectivity. The CGRP receptor (RAMP1:CLR) favors CGRP binding, whereas the AM (RAMP2:CLR) and AM (RAMP3:CLR) receptors favor AM binding. How AM2/IMD binds the receptors and how RAMPs modulate its binding is unknown. Here, we show that AM2/IMD binds the three purified RAMP-CLR extracellular domain (ECD) complexes with a selectivity profile that is distinct from those of CGRP and AM. AM2/IMD bound all three ECD complexes but preferred the CGRP and AM receptor complexes. A 2.05 Å resolution crystal structure of an AM2/IMD antagonist fragment-bound RAMP1-CLR ECD complex revealed that AM2/IMD binds the complex through a unique triple β-turn conformation that was confirmed by peptide and receptor mutagenesis. Comparisons of the receptor-bound conformations of AM2/IMD, AM, and a high-affinity CGRP analog revealed differences that may have implications for biased signaling. Guided by the structure, enhanced-affinity AM2/IMD antagonist variants were developed, including one that discriminates the AM and AM receptors with ∼40-fold difference in affinities and one stabilized by an intramolecular disulfide bond. These results reveal differences in how the three peptides engage the receptors, inform development of AM2/IMD-based pharmacological tools and therapeutics, and provide insights into RAMP modulation of receptor pharmacology.

PubMed: 30139742
DOI: 10.1074/jbc.RA118.005062

Experimental method

X-RAY DIFFRACTION (2.05 Å)