Oligomerization of the E. coli Core RNA Polymerase: Formation of (α2ββ'ω)2–DNA Complexes and Regulation of the Oligomerization by Auxiliary Subunits
Figure 1
Determination of the molecular masses of the core RNA polymerase and the RNA polymerase holoenzyme under non-denaturing conditions.
A. Schematic for the RNA polymerase purification procedure. Samples of the purified core RNA polymerase (lane 2) and the RNA polymerase holoenzyme (lane 3) (∼4 µg of each complex) are shown on a Coomassie-stained SDS gel. The core RNA polymerase and the RNA polymerase holoenzyme were purified as described in Materials and Methods. B. Determination of the molecular masses of the core RNA polymerase and the RNA polymerase holoenzyme by gel-permeation chromatography on a Superose 6 HR 10/300 column. Chromatography was carried out as described in Materials and Methods. Native protein markers (Sigma) were: Alcohol Dehydrogenase (AD, 150 kDa), Apoferritin (AF, 443 kDa), Thyroglobulin (TG, 669 kDa), and Blue Dextran (BD, 2000 kDa). Each marker was run twice (black crosses and blue rectangles). Elution times for the RNA polymerase samples are indicated.