Ala-scan of ghrelin (1-14): interaction with the recombinant human ghrelin receptor

Peptides. 2004 Jun;25(6):959-65. doi: 10.1016/j.peptides.2004.03.010.


Ghrelin, a 28 residues acylated peptide, is the natural ligand of the growth-hormone secretagogue receptor (GHS-R), which also interacts with small synthetic peptides. We investigated the importance of each of the first 14 N-terminal residues by Ala replacement (Ala-scan) and also of the N-terminal positive charge, on the recombinant GHS-R expressed in HEK293 or CHO cells by binding, IP and Ca(2+) assays. Nearly all of the replacements had no significant effect on the ligand binding or IP(3)/Ca(2+) stimulation. Exceptions were the modification of the N-terminal residue to [A(1)]- or N(alpha)-acetyl-ghrelin (1-14), confirming the requirement for the positive charge at the amino-terminus. Mutation of [F(4)]- to [A(4)]- or [Y(4)]-ghrelin (1-14), were detrimental suggesting direct interaction with the GHS-R. [A(8)] and [Y(8)] were more potent than ghrelin (1-14), implying that the naturally occurring Glu(8) residue may not be the optimal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alanine / chemistry
  • Amino Acid Substitution
  • Animals
  • Binding, Competitive
  • CHO Cells
  • Cricetinae
  • Cricetulus
  • Ghrelin
  • Humans
  • Peptide Hormones / chemistry*
  • Peptide Hormones / genetics
  • Peptide Hormones / metabolism*
  • Protein Interaction Mapping
  • Receptors, G-Protein-Coupled / genetics
  • Receptors, G-Protein-Coupled / metabolism*
  • Receptors, Ghrelin
  • Recombinant Proteins / metabolism


  • Ghrelin
  • Peptide Hormones
  • Receptors, G-Protein-Coupled
  • Receptors, Ghrelin
  • Recombinant Proteins
  • Alanine