CopY family regulators (also known as CopR, TcrY,or AtkY) act as copper-responsive transcriptional repressors in Firmicutes [18837698, 21295546, 10069368, 16151212, 11238972]. Copper is an essential nutrient, acting as a cofactor for several enzymes, however copper excess is toxic to the cell and its cellular concentration is tightly controlled. CopY-like regulators control expression of genes responsible for copper uptake and efflux, as well as copper chaperones. CopY regulators bind target promoters and thus block transcription of corresponding genes. When copper concentration in the cell increases, zinc ion inside of the CopY protein is replaced by copper ion, that cause CopY dissociation from DNA and derepression of cop genes transcription.
CopY-like proteins constitute a unique family (PF03965) including an N-terminal DNA binding region and a C-terminal region responsible for metal-binding and dimerization.