Coordinates the expression of genes functioning in central metabolism and its associated pathways. Acts as both a transcriptional activator and a repressor in response to carbon source availability. Binds to an inverted palindromic sequence in the promoters or ORFs of target genes. Does not bind DNA in the presence of high glucose or glycerol. Contains an N-terminal DNA-binding domain and a C-terminal sugar-binding domain. Deletion causes severe growth defect in various conditions, such as nutrient starvation in defined media, metal depletion and excess, and oxidative stress. Belongs to the transcriptional regulator TrmB family. Extended N-terminus.