Pleiotropic transcription regulator CodY was characterized in various Gram-positive bacteria as a repressor of the stationary-phase and sporulation genes and an activator of other genes, e.g. those are involved in the carbon overflow metabolism . Many of CodY-regulated genes are involved in nitrogen- or carbon metabolism, virulence-assotitation gene expression, transport of macromolecules and transcriptional regulation [20363936, 21097623].The repressor function of CodY is modulated by two different effectors, GTP and branched-chain amino acids (isoleucine, leucine, and valine) , which may be viewed as sensors of the energetic and metabolic status of the cell, respectively .
These co-repressors act independently and additively to increase the affinity of CodY for its target DNA sites. As a result of the decrease in the intracellular pools of GTP and branched-chain amino acids when cells enter the stationary phase, CodY becomes less active, leading to the induction of genes that are targets of CodY repression [19651859
]. CodY regulators contain a C-terminal winged HTH DNA binding domain (PF08222) and an N-terminal GAF domain (PF06018) responsible for binding of effectors.