Structure-activity studies of RFamide peptides reveal subtype-selective activation of neuropeptide FF1 and FF2 receptors

ChemMedChem. 2011 Jun 6;6(6):1081-93. doi: 10.1002/cmdc.201100089. Epub 2011 May 4.


Selectivity is a major issue in closely related multiligand/multireceptor systems. In this study we investigated the RFamide systems of hNPFF₁R and hNPFF₂R that bind the endogenous peptide hormones NPFF, NPAF, NPVF, and NPSF. By use of a systematic approach, we characterized the role of the C-terminal dipeptide with respect to agonistic properties using synthesized [Xaa 7]NPFF and [Xaa 8]NPFF analogues. We were able to identify only slight differences in potency upon changing the position of Arg 7, as all modifications resulted in identical behavior at the NPFF₁R and NPFF₂R. However, the C-terminal Phe 8 was able to be replaced by Trp or His with only a minor loss in potency at the NPFF₂R relative to the NPFF₁R. Analogues with shorter side chains, such as α-amino-4-guanidino butyric acid ([Agb 7]NPFF) or phenylglycine ([Phg 8]NPFF), decreased efficacy for the NPFF₁ R to 25-31 % of the maximal response, suggesting that these agonist-receptor complexes are more susceptible to structural modifications. In contrast, mutations to the conserved Asp 6.59 residue in the third extracellular loop of both receptors revealed a higher sensitivity toward the hNPFF₂R receptor than toward hNPFF₁R. These data provide new insight into the subtype-specific agonistic activation of the NPFF₁ and NPFF(2) receptors that are necessary for the development of selective agonists.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • COS Cells
  • Chlorocebus aethiops
  • Humans
  • Molecular Sequence Data
  • Neuropeptides / chemistry
  • Neuropeptides / pharmacology*
  • Point Mutation
  • Receptors, Neuropeptide / agonists*
  • Receptors, Neuropeptide / chemistry*
  • Receptors, Neuropeptide / genetics
  • Receptors, Neuropeptide / metabolism
  • Sequence Alignment
  • Structure-Activity Relationship*


  • Neuropeptides
  • RFamide peptide
  • Receptors, Neuropeptide
  • neuropeptide FF receptor