The importance of valine 114 in ligand binding in β2- adrenergic receptor

Makoto Arakawa, Naveena Yanamala, Jasbir Upadhyaya, Andrew Halayko, Judith Klein-Seetharaman, Prashen Chelikani

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

G-protein coupled receptors (GPCRs) are transmembrane signaling molecules, with a majority of them performing important physiological roles. β2-Adrenergic receptor (β2-AR) is a well-studied GPCRs that mediates natural responses to the hormones adrenaline and noradrenaline. Analysis of the ligand-binding region of β2-AR using the recently solved high-resolution crystal structures revealed a number of highly conserved amino acids that might be involved in ligand binding. However, detailed structure-function studies on some of these residues have not been performed, and their role in ligand binding remains to be elucidated. In this study, we have investigated the structural and functional role of a highly conserved residue valine 114, in hamster β2-AR by site-directed mutagenesis. We replaced V114 in hamster β2-AR with a number of amino acid residues carrying different functional groups. In addition to the complementary substitutions V114I and V114L, the V114C and V114E mutants also showed significant ligand binding and agonist dependent G-protein activation. However, the V114G, V114T, V114S, and V114W mutants failed to bind ligand in a specific manner. Molecular modeling studies were conducted to interpret these results in structural terms. We propose that the replacement of V114 influences not only the interaction of the ethanolamine side-chains but also the aryl-ring of the ligands tested. Results from this study show that the size and orientation of the hydrophobic residue at position V114 in β2-AR affect binding of both agonists and antagonists, but it does not influence the receptor expression or folding. Published by Wiley-Blackwell.

Original languageEnglish (US)
Pages (from-to)85-93
Number of pages9
JournalProtein Science
Volume19
Issue number1
DOIs
StatePublished - Jan 2010
Externally publishedYes

Keywords

  • Beta-adrenergic receptor
  • Ligand binding
  • Molecular modeling
  • Site-directed mutagenesis
  • Valine 114

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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