Evolutionary relationships between sugar kinases and transcriptional repressors in bacteria.

We have characterized a new family of proteins (the ROK family) which includes six transcriptional repressors for sugar catabolic operons, three sugar kinases, and three unidentified open reading frames. Analysis of the aligned sequences and phylogenetic tree construction allow predictions regarding the functional nature of conserved domains and residues within these proteins as well as the pathway of evolutionary divergence that gave rise to the family.