Gene organizations, sequence alignments, consensus sequences, and amino acids relevant for Pr to Pfr transitions. (a) Gene organization related to BphPs from S. aurantiaca DW4/3–1, Chondromyces apiculatus, Cystobacter fuscus, Myxococcus fulvus HW-1 and Corallococcus coralloides DSM 2259 (heme oxygenase opens the tetrapyrrole ring, the response regulator has histidine kinase activity). (b) Partial sequence alignment of BphPs. The PASDIP consensus sequence as well as position 289 of the Thr to His mutation in SaBphP1 are marked in green, the PRXSF consensus sequence is marked in pink, the Cys to which the BV is bound is marked in gray. SaBphP1 and SaBphP2 (S. aurantiaca DW4/3–1); CaBphP1 and CaBphP2 (C. apiculatus DSM 436); CfBphP1, CfBphP2 and CfBphP3 (C. fuscus); MfBphP (M. fulvus HW-1); CcBphP (C. coralloides DSM 2259); DrBphP (D. radiodurans); RpBphP2 and RpBphP3 (R. palustris CGA009); PaBphP (P. aeruginosa PA01); PsBphP (Pseudomonas syringae pv. tomato T1); Cph1 (Synechocystis PCC6803).