Ancestral Reconstruction of LacI/GalR Transcriptional Regulators

The LacI/GalR family comprises an array of transcriptional repressors involved predominantly in the regulation of metabolic pathways in prokaryotes. Members of the family have an N-terminal DNA-binding domain and a regulatory solute-binding domain that shares strong structural homology with periplasmic-binding proteins. Activation of the DNA-binding domain occurs via allosteric interactions upon effector ligand binding in the solute-binding domain. The aim of this research is to elucidate the molecular basis for the evolution of allostery within the LacI/GalR family by biophysically and functionally characterizing reconstructed ancestral proteins along an evolutionary trajectory. We aim to highlight how this may be applied to engineer novel transcriptional regulators necessary for metabolic engineering and synthetic biology.