A novel immunity system for bacterial nucleic acid degrading toxins and its recruitment in various eukaryotic and DNA viral systems

Zhang, Dapeng; Iyer, Lakshminarayan M.; Aravind, L.

The current study points to the remarkable flexibility of SUKH domains in mediating different protein-protein interactions. In a sense, this situation resembles what has earlier been observed with certain scaffolds like the immunoglobulin domain and the leucine-rich repeats of various immunity-related proteins of eukaryotes (98, 99) . The ability of the SUKH scaffold to accommodate diverse binding partners makes it a potential candidate as a template for protein engineering to generate novel binding capabilities. Likewise, the C-terminal diversification of the toxin domain could also have biotechnological utility as a model for generating secreted proteins that differ extensively in a given module but retain a constant N-terminal part. We hope that this characterization of the SUKH superfamily and identification of the associated nuclease toxin families provides new leads for the future exploration of the manifold implications of the systems discussed here.