FIG. 1.

Alignment of RegA homologues present in genome databases. The input domain contains a conserved phosphate-accepting aspartate residue, denoted by a star. The output domain contains the three-helical bundle DNA-binding domain, denoted by α6, α7, and α8. The flexible linker region, which connects the input and output domains, is labeled Hinge. The alanine responsible for the RegA* phenotype is indicated by an octagon. Red residues represent 100% conserved amino acids, blue residues represent 50% or higher conserved amino acids, and yellow residues represent conservative amino acid changes.