FIG. 5.

Clustal W-aligned sequences of arginine regulators from B. subtilis 168 (Bsu_AhrC), B. stearothermophilus (Bst_ArgR), L. lactis MG1363 (Ll_ArgR and Ll_AhrC), and E. coli K-12 (Ec_ArgR). Shaded residues are identical in more than 50% of the sequences. “H” indicates the hinge region residues connecting the C- and N-terminal domains, as determined from the B. stearothermophius ArgR crystal structure (34). Functions of specific residues are specified as follows: involved in operator recognition and binding (•), involved in subunit multimerization (▪), and involved in arginine binding (□). ISS1 integration sites in ArgR_Ll and integrant strain names are indicated by ▾.