Multiple N-methylation of MT-II backbone amide bonds leads to melanocortin receptor subtype hMC1R selectivity: pharmacological and conformational studies

J Am Chem Soc. 2010 Jun 16;132(23):8115-28. doi: 10.1021/ja101428m.


Multiple N-methylation is a novel technology to improve bioavailability of peptides and increase receptor subtype selectivity. This technique has been applied here to the superpotent but nonselective cyclic peptide MT-II. A library of all possible 31 backbone N-methylated derivatives has been synthesized and tested for binding and activation at melanocortin receptor subtypes 1, 3, 4, and 5. It turned out that selectivity is improved with every introduced N-methyl group, resulting in several N-methylated selective and potent agonists for the hMC1R. The most potent of these derivatives is N-methylated on four out of five amide bonds in the cyclic structure. Its solution structure indicates a strongly preferred backbone conformation that resembles other alpha-MSH analogs but possesses much less flexibility and in addition distinct differences in the spatial arrangement of individual amino acid side chains.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amides / chemistry*
  • Binding, Competitive
  • Cell Line
  • Drug Design*
  • Humans
  • Methylation
  • Molecular Dynamics Simulation
  • Nitrogen / chemistry*
  • Nuclear Magnetic Resonance, Biomolecular
  • Peptides, Cyclic / chemistry*
  • Peptides, Cyclic / metabolism*
  • Peptides, Cyclic / pharmacology
  • Protein Conformation
  • Receptor, Melanocortin, Type 1 / metabolism*
  • Receptors, G-Protein-Coupled / metabolism
  • Substrate Specificity


  • Amides
  • Peptides, Cyclic
  • Receptor, Melanocortin, Type 1
  • Receptors, G-Protein-Coupled
  • Nitrogen