Nov 29


This webserver provides a database listing basic properties of LAGLIDADG homing endonucleases (LHEs) with validated biochemical activity and known target site specificity. It also supports web-based searches of DNA sequences (ranging from single or multiple genes to entire genomic reads) for potential target sites that might be recognized either by wild-type or by engineered variants of those endonucleases. Searches can be performed using several different Position Weight Matrices (PWMs) or scoring algorithms, ranging from:

  1. Searches for perfect identity across the 'Central 4' basepairs for given LHEs
  2. Searches for highest identity to the entire 22 basepair recognition site for given LHEs
  3. Searches for highest scored matches against 'Fidelity-based’ PWMs (that account for variable levels of recognition fidelity exhibited by wild-type enzymes at individual basepair positions)
  4. Searches for combinations of three basepair modules of DNA sequences across the entire target site that are engineerable based on modular targets screens for cleavage activity conducted using yeast surface display assays

All scoring matrices and algorithms are curated within our database, to allow for easy access in the search process. Only endonucleases with biochemically validated endonuclease activity, specificity and biophysical properties that are amenable to engineering are used in this database and server. Additional homing endonucleases and matrices may also be added using the tool allowing for custom searches.

For further information, please read the FAQ page.

If you use the LAHEDES webserver for your research, please cite the following paper:

Taylor, G. K., Petrucci, L. H., Lambert, A.R., Baxter, S.K., Jarjour, J. and Stoddard, B. L. (2012) "LAHEDES: the LAGLIDADG homing endonuclease database and engineering server" Nucleic Acids Research 40 (W1): W110-W116. PubMED: 22570419

This website is free and open to all users without a login requirement.