Figure 2.

(A) Chemical structures of Myx and Lpm. (B) Overlap of the Lpm and Myx binding sites. Amino acids substitutions conferring resistance to Lpm²⁷ are shown in CPK colored in cyan for β subunit (T. thermophilus Q¹⁰¹⁸, V¹⁰⁸⁷, N¹⁰⁶⁴) and magenta (R⁶¹³) or dark blue (R⁸⁷, P⁵²⁶) for β' subunit, σ_3.2HL is shown as green ribbons and Myx is shown in ball-and-stick and orange. R⁶¹³ is shown in two conformations—as in holoenzyme and as in the RNAP-Myx complex.¹ (C) Model of the mechanism of Lpm and Myx action. RNAP core is shown as a gray ellipse. The σ subunit is shown in green, region 3.2 is shown as a green triangle, and the β' switch-2 is shown as a blue rectangle. The +1 base of the promoter is indicated by a red circle.