The Protein Interactions Expert

1-by-1 Y2H & Interaction Domain Mapping

a scientist reviewing results

1-by-1 Y2H and Interaction Domain Mapping (IDM) are robust and versatile techniques to investigate interactions and delineate interacting domains.

Get insights into your favorite protein interactions and receive publication-grade figures.

CONTACT our experts to design the protein fragments to test, from your candidate partners.


  • Test the interaction between two candidate proteins
  • Compare the binding of wild-type and mutant proteins or between isoforms
  • Map the exact interacting domain on a protein

Molecules Tested

  • Full- length wild-type or mutant protein
  • Protein fragments or peptides
  • Cytoplasmic or extracellular proteins
  • Loops, tails or whole membrane proteins

How does it work?

1-by-1 Y2H and Interaction Domain Mapping take advantage of our ULTImate Y2H™ Yeast Two-Hybrid technology.

The two proteins or protein fragments to be tested are cloned in frame with LexA or Gal4 DNA binding domain and Gal4 activation domain.

In yeast, the interaction between the two fragments leads to the reconstitution of a functional transcription factor and activates the transcription of HIS3 and LacZ reporter genes.
HIS3 allows yeast cells to grow on a medium lacking histidine, whereas LacZ offers quantitative measurement of the interaction’s strength thanks to colorimetric or luminescent ß-galactosidase substrates.

To delineate the interacting domain on each protein, multiple fragments are cloned by gap repair in yeast and tested for their interaction with the protein partner.
For integral membrane proteins the process is adapted and takes advantage of our MBmate Y2H* protocol.


  • Simple, fast and robust pairwise interaction test
  • Quantification of the strength of the interactions
  • Deeper characterization of your interaction and the domains involved
  • Publication-grade illustrations including all positive and negative controls
  • Scientific assistance to select the domains to be tested


  • Electronic pictures of solid growth assays
  • Graphs for the quantitative LacZ assays
  • Detailed experimental methods

*This technology is protected under patents owned by or issued to Dualsystems Biotech, Switzerland

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