FIG 1.
Cryo-EM structure determinations of M. smegmatis RNAP complexes. (Top row) Secondary structures of two forms of RNAP from M. smegmatis as observed in the experimental cryo-EM densities: core (left) and holoenzyme (right, RNAP in complex with primary sigma factor, σA). Subunits are colored as follows: β, yellow; β′, green; α, gray; α′, cyan; ω, orange; σA, magenta. (Middle row) Cryo-EM maps are filtered and colored according to local resolution calculated with the RELION software package (see Fig. S3 for more detail). (Bottom row) Cryo-EM maps, together with fit of secondary structure models of M. smegmatis RNAP complexes. Maps are visualized as 0.5 transparent at 0.08 volume threshold in Chimera (see Fig. S4 for more detail). Color coding is as described for the top row.