Conserved amino acid residues in the C-terminal region of P. gingivalis HmuR compared with representative hemoglobin, hemoglobin-haptoglobin, heme, vitamin B12 and siderophore receptors. Conserved amino acids between receptors and the consensus sequence are indicated in boldface letters. The positions of the amino acids were numbered according to the codons from the NCBI database. Pg, P. gingivalis; Hd, Haemophilus ducreyi; Hi, Haemophilus influenzae; Vv, Vibrio vulnificus; Vc, Vibrio cholerae; Sd, Shigella dysenteriae; Ye, Yersinia enterocolitica; Nm, Neisseria meningitidis; Sm, Serratia marcescens; Ec, Escherichia coli.