Figure 2

In vitro assembly of Francisella α ₂ β RNAP subassembly. A. Reactions were assembled and analyzed as described in Figure 1 legend. "W" -wash with excess of loading buffer. Proteins were eluted with a buffer containing 100 mM imidazole. B. Sequence alignment of the α subunit segment involved in dimerization and interaction with the β subunit. A segment of E. coli α subunit (amino acids 1-59) is shown at the top (single-letter amino acid code). Corresponding sequences from Thermus aquaticus (Taq), Thermus thermophilus (Tth), and Francisella tularensis RpoA variants are aligned below. Dots indicate identities, hyphens - gaps. Amino acids highlighted in red form a cluster important for α homodimer formation in E. coli. Amino acid highlighted in blue is responsible for the interaction with β.