Molecular approximations between residues 21 and 23 of secretin and its receptor: Development of a model for peptide docking with the amino terminus of the secretin receptor

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

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The structurally unique amino-terminal domain of class II G protein-coupled receptors is critically important for ligand binding and receptor activation. Understanding the precise role it plays requires detailed insights into the molecular basis of its ligand interactions and the conformation of the ligand-receptor complex. In this work, we used two high-affinity, full-agonist, secretin-like photolabile probes having sites for covalent attachment in positions 21 and 23 and used sequential proteolysis and sequencing of the labeled region of the receptor to identify two new spatial approximation constraints. The position 21 probe labeled receptor residue Arg15, whereas the position 23 probe labeled receptor residue Arg21. A homology model of the amino-terminal domain of the secretin receptor was developed using the NMR structure of the analogous domain of the corticotropin-releasing factor receptor. This was attached to a homology model of the secretin receptor transmembrane bundle, with the two domains oriented relative to each other based on continuity of the peptide backbone and by imposing a distance restraint recently identified between the amino-terminal WDN sequence and the region of the helical bundle above transmembrane segment six. Secretin was docked to this model using seven sets of spatial approximation constraints identified in previous photoaffinity labeling studies. This model was found to fully accommodate all existing constraints, as well as the two new approximations identified in this work.

Original languageEnglish (US)
Pages (from-to)280-290
Number of pages11
JournalMolecular Pharmacology
Volume72
Issue number2
DOIs
StatePublished - Aug 2007

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Secretin
Ligands
Peptides
Corticotropin-Releasing Hormone Receptors
G-Protein-Coupled Receptors
Proteolysis
secretin receptor

ASJC Scopus subject areas

  • Pharmacology

Cite this

Molecular approximations between residues 21 and 23 of secretin and its receptor : Development of a model for peptide docking with the amino terminus of the secretin receptor. / Dong, Maoqing; Lam, Polo C H; Gao, Fan; Hosohata, Keiko; Pinon, Delia I.; Sexton, Patrick M.; Abagyan, Ruben; Miller, Laurence J.

In: Molecular Pharmacology, Vol. 72, No. 2, 08.2007, p. 280-290.

Research output: Contribution to journalArticle

Dong, Maoqing ; Lam, Polo C H ; Gao, Fan ; Hosohata, Keiko ; Pinon, Delia I. ; Sexton, Patrick M. ; Abagyan, Ruben ; Miller, Laurence J. / Molecular approximations between residues 21 and 23 of secretin and its receptor : Development of a model for peptide docking with the amino terminus of the secretin receptor. In: Molecular Pharmacology. 2007 ; Vol. 72, No. 2. pp. 280-290.
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