Spatial approximation between secretin residue five and the third extracellular loop of its receptor provides new insight into the molecular basis of natural agonist binding

Maoqing Dong, Polo C H Lam, Delia I. Pinon, Patrick M. Sexton, Ruben Abagyan, Laurence J Miller

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

The amino terminus of class II G protein-coupled receptors plays an important role in ligand binding and receptor activation. Understanding of the conformation of the amino-terminal domain of these receptors has been substantially advanced with the solution of nuclear magnetic resonance and crystal structures of this region of receptors for corticotrophin-releasing factor, pituitary adenylate cyclase-activating polypeptide, and gastric inhibitory polypeptide. However, the orientation of the amino terminus relative to the receptor core and how the receptor gets activated upon ligand binding remain unclear. In this work, we have used photoaffinity labeling to identify a critical spatial approximation between residue five of secretin and a residue within the proposed third extracellular loop of the secretin receptor. This was achieved by purification, deglycosylation, cyanogen bromide cleavage, and sequencing of labeled wild-type and mutant secretin receptors. This constraint has been used to refine our evolving molecular model of secretin docked at the intact receptor, which for the first time includes refined helical bundle and loop regions and reflects a peptide-binding groove within the receptor amino terminus that directs the amino terminus of the peptide toward the receptor body. This model is fully consistent with the endogenous agonist mechanism for class II G protein-coupled receptor activation, where ligand binding promotes the interaction of a portion of the receptor amino terminus with the receptor body to activate it.

Original languageEnglish (US)
Pages (from-to)413-422
Number of pages10
JournalMolecular Pharmacology
Volume74
Issue number2
DOIs
StatePublished - Aug 2008

Fingerprint

Secretin
G-Protein-Coupled Receptors
Ligands
Gastric Inhibitory Polypeptide
Pituitary Adenylate Cyclase-Activating Polypeptide
Corticotropin-Releasing Hormone Receptors
Cyanogen Bromide
Molecular Models
Peptide Receptors
Magnetic Resonance Spectroscopy
Peptides
secretin receptor

ASJC Scopus subject areas

  • Pharmacology

Cite this

Spatial approximation between secretin residue five and the third extracellular loop of its receptor provides new insight into the molecular basis of natural agonist binding. / Dong, Maoqing; Lam, Polo C H; Pinon, Delia I.; Sexton, Patrick M.; Abagyan, Ruben; Miller, Laurence J.

In: Molecular Pharmacology, Vol. 74, No. 2, 08.2008, p. 413-422.

Research output: Contribution to journalArticle

@article{4c44db5852094d678b5405acdd7ce2ae,
title = "Spatial approximation between secretin residue five and the third extracellular loop of its receptor provides new insight into the molecular basis of natural agonist binding",
abstract = "The amino terminus of class II G protein-coupled receptors plays an important role in ligand binding and receptor activation. Understanding of the conformation of the amino-terminal domain of these receptors has been substantially advanced with the solution of nuclear magnetic resonance and crystal structures of this region of receptors for corticotrophin-releasing factor, pituitary adenylate cyclase-activating polypeptide, and gastric inhibitory polypeptide. However, the orientation of the amino terminus relative to the receptor core and how the receptor gets activated upon ligand binding remain unclear. In this work, we have used photoaffinity labeling to identify a critical spatial approximation between residue five of secretin and a residue within the proposed third extracellular loop of the secretin receptor. This was achieved by purification, deglycosylation, cyanogen bromide cleavage, and sequencing of labeled wild-type and mutant secretin receptors. This constraint has been used to refine our evolving molecular model of secretin docked at the intact receptor, which for the first time includes refined helical bundle and loop regions and reflects a peptide-binding groove within the receptor amino terminus that directs the amino terminus of the peptide toward the receptor body. This model is fully consistent with the endogenous agonist mechanism for class II G protein-coupled receptor activation, where ligand binding promotes the interaction of a portion of the receptor amino terminus with the receptor body to activate it.",
author = "Maoqing Dong and Lam, {Polo C H} and Pinon, {Delia I.} and Sexton, {Patrick M.} and Ruben Abagyan and Miller, {Laurence J}",
year = "2008",
month = "8",
doi = "10.1124/mol.108.047209",
language = "English (US)",
volume = "74",
pages = "413--422",
journal = "Molecular Pharmacology",
issn = "0026-895X",
publisher = "American Society for Pharmacology and Experimental Therapeutics",
number = "2",

}

TY - JOUR

T1 - Spatial approximation between secretin residue five and the third extracellular loop of its receptor provides new insight into the molecular basis of natural agonist binding

AU - Dong, Maoqing

AU - Lam, Polo C H

AU - Pinon, Delia I.

AU - Sexton, Patrick M.

AU - Abagyan, Ruben

AU - Miller, Laurence J

PY - 2008/8

Y1 - 2008/8

N2 - The amino terminus of class II G protein-coupled receptors plays an important role in ligand binding and receptor activation. Understanding of the conformation of the amino-terminal domain of these receptors has been substantially advanced with the solution of nuclear magnetic resonance and crystal structures of this region of receptors for corticotrophin-releasing factor, pituitary adenylate cyclase-activating polypeptide, and gastric inhibitory polypeptide. However, the orientation of the amino terminus relative to the receptor core and how the receptor gets activated upon ligand binding remain unclear. In this work, we have used photoaffinity labeling to identify a critical spatial approximation between residue five of secretin and a residue within the proposed third extracellular loop of the secretin receptor. This was achieved by purification, deglycosylation, cyanogen bromide cleavage, and sequencing of labeled wild-type and mutant secretin receptors. This constraint has been used to refine our evolving molecular model of secretin docked at the intact receptor, which for the first time includes refined helical bundle and loop regions and reflects a peptide-binding groove within the receptor amino terminus that directs the amino terminus of the peptide toward the receptor body. This model is fully consistent with the endogenous agonist mechanism for class II G protein-coupled receptor activation, where ligand binding promotes the interaction of a portion of the receptor amino terminus with the receptor body to activate it.

AB - The amino terminus of class II G protein-coupled receptors plays an important role in ligand binding and receptor activation. Understanding of the conformation of the amino-terminal domain of these receptors has been substantially advanced with the solution of nuclear magnetic resonance and crystal structures of this region of receptors for corticotrophin-releasing factor, pituitary adenylate cyclase-activating polypeptide, and gastric inhibitory polypeptide. However, the orientation of the amino terminus relative to the receptor core and how the receptor gets activated upon ligand binding remain unclear. In this work, we have used photoaffinity labeling to identify a critical spatial approximation between residue five of secretin and a residue within the proposed third extracellular loop of the secretin receptor. This was achieved by purification, deglycosylation, cyanogen bromide cleavage, and sequencing of labeled wild-type and mutant secretin receptors. This constraint has been used to refine our evolving molecular model of secretin docked at the intact receptor, which for the first time includes refined helical bundle and loop regions and reflects a peptide-binding groove within the receptor amino terminus that directs the amino terminus of the peptide toward the receptor body. This model is fully consistent with the endogenous agonist mechanism for class II G protein-coupled receptor activation, where ligand binding promotes the interaction of a portion of the receptor amino terminus with the receptor body to activate it.

UR - http://www.scopus.com/inward/record.url?scp=47949116776&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=47949116776&partnerID=8YFLogxK

U2 - 10.1124/mol.108.047209

DO - 10.1124/mol.108.047209

M3 - Article

C2 - 18467541

AN - SCOPUS:47949116776

VL - 74

SP - 413

EP - 422

JO - Molecular Pharmacology

JF - Molecular Pharmacology

SN - 0026-895X

IS - 2

ER -