FIG. 2.

Genetic context of the Gp0.7 phosphorylation site in the E. coli RNAP β′ subunit. The thick bar at the top represents the 1,407-amino-acid-long β′ subunit of E. coli RNAP. Hatched boxes labeled A to H represent segments highly conserved in evolution (1). The E. coli hypervariable region that contains the Gp0.7 phosphorylation site and that is absent from β′ homologues from gram-positive bacteria (46) is shown by an open box, and its sequence is expanded underneath. The E. coli sequence (E. c.) is aligned with homologous sequences from Yersinia pestis (Y. p.), Kluyvera cryocrescens (K. c.), Caulobacter crescentus (C. c.), and Bacillus subtilis (B. s.). Dots indicate identity to the E. coli sequence, and dashes indicate gaps. Methionine residues that flank the CNBr fragment that contains the phosphorylation site are indicated above the E. coli sequence, threonine residues that are contained within this CNBr fragment are italicized, and two phosphomimetic substitutions used in this work are indicated. The bar above the E. coli sequence shows the deletion of the β′ downstream jaw in the E. coli JE1144 cells.