FIG. 3.

The domain structure of σ³². A schematic map reveals the domain structure and conserved regions of σ³². Note that domains are divided into subdomains as follows: domain 2 is comprised of subdomains 1.2 to 2.4 and encompasses amino acids 16 to 126, domain 3 is comprised of subdomains 3.1 and 3.2 and encompasses amino acids 127 to 177, and domain 4 is comprised of subdomains 4.1 and 4.2 and encompasses amino acids 213 to 280. The RpoH box is comprised of amino acids 132 to 141. Regions that bind RNA polymerase and promoter DNA are shown below the schematic; features specific to σ³² are indicated above the schematic. “Activity/stability mutants” marks the position of mutations in σ³² that affect the stability and/or activity of σ³².