Fig. 6

Scheme presenting gene arrangement at cyaC(A), the CyaC×CycR×cAMP-Clr sensor complex (B), and the transcriptional regulatory complex CycR×cAMP-Clr (C). (A) Adenylate cyclase CyaC forms with CycR the backbone of the CyaC×CycR×cAMP-Clr sensor complex. Cyclase activity of CyaC can be activated after oxidation by quinones (Q), resulting in cAMP formation (see [5]). Binding of Clr to CyaC and CycR is factor dependent. (B) The CycR×cAMP-Clr regulatory complex binds to CycR/Clr regulated promoters after detachment from CyaC and diffusion in the cytosol. The distal (B_D) and proximal (B_P) hemeB, and the [2Fe-2 S]²⁺ cluster of CyaC are indicated [5]