Targeting EphA2-Sam and Its Interactome: Design and Evaluation of Helical Peptides Enriched in Charged Residues

Chembiochem. 2016 Nov 17;17(22):2179-2188. doi: 10.1002/cbic.201600413. Epub 2016 Oct 20.

Abstract

The EphA2 receptor controls diverse physiological and pathological conditions and its levels are often upregulated in cancer. Targeting receptor overexpression, through modulation of endocytosis and consequent degradation, appears to be an appealing strategy for attacking tumor malignancy. In this scenario, the Sam domain of EphA2 plays a pivotal role because it is the site where protein regulators of endocytosis and stability are recruited by means of heterotypic Sam-Sam interactions. Because EphA2-Sam heterotypic complexes are largely based on electrostatic contacts, we have investigated the possibility of attacking these interactions with helical peptides enriched in charged residues. Several peptide sequences with high predicted helical propensities were designed, and detailed conformational analyses were conducted by diverse techniques including NMR, CD, and molecular dynamics (MD) simulations. Interaction studies were also performed by NMR, surface plasmon resonance (SPR), and microscale thermophoresis (MST) and led to the identification of two peptides capable of binding to the first Sam domain of Odin. These molecules represent early candidates for the generation of efficient Sam domain binders and antagonists of Sam-Sam interactions involving EphA2.

Keywords: EphA2; Sam domain; cancer; conformational analysis; drug design; helical peptides.

MeSH terms

  • Amino Acid Sequence
  • Circular Dichroism
  • Drug Design
  • Kinetics
  • Magnetic Resonance Spectroscopy
  • Molecular Dynamics Simulation
  • Peptides / chemical synthesis
  • Peptides / chemistry*
  • Peptides / metabolism
  • Protein Binding
  • Protein Structure, Secondary
  • Receptor, EphA2 / chemistry*
  • Receptor, EphA2 / genetics
  • Receptor, EphA2 / metabolism
  • Recombinant Proteins / biosynthesis
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification
  • Solid-Phase Synthesis Techniques
  • Sterile Alpha Motif
  • Surface Plasmon Resonance

Substances

  • Peptides
  • Recombinant Proteins
  • Receptor, EphA2