Homology models of the globin, middle, and diguanylate cyclase domains of PccGCS. (A) Globin domain (heme represented by stick-and-ball structure). (B) Middle domain showing the conserved histidine-237 and lysine-238 in cyan. (C) Diguanylate cyclase domain (GGEEF active site residues are shown in orange). Homology models were made for both PccGCS and BpeGReg using EcDosC crystal structures and the Protein Homology/analogY Recognition Engine V2.0 (PHYRE 2) tool [35]. Structure molecular graphics were created using the UCSF Chimera package [39].