REL PDBe PDBe PDBe 2010-10-04 2010-10-08 2010-11-01 2012-10-24 Fernandez-Tornero C Bottcher B Rashid UJ Steuerwald U Florchinger B Devos DP Lindner D Muller CW Transcription, RNA polymerase III, elongation complex, transcription initiation, transcription elongation, transcription termination Fernandez-Tornero C Bottcher B Rashid UJ Steuerwald U Florchinger B Devos DP Lindner D Muller CW EMBO J. 29 3762 3772 2010 20967027 doi:10.1038/emboj.2010.266 RNA Polymerase III elongation complex RNA Polymerase III elongation complex

Sample was monodisperse

Transcription bubble, RNA Pol III complex 2 0.7 0.7 Native mass spectrometry Transcription bubble synthetic construct 0.03

An artificial transcription bubble was prepared as described (Kettenberger et al., 2004) and was added in five molar excess to purified Pol III. Unbound transcription bubble was subsequently removed using size exclusion chromatography

DNA/RNA OTHER true RNA Polymerase III Saccharomyces cerevisiae Baker's yeast Nuclear 0.7 0.7 One complex of 17 different polypeptides false singleParticle particle 0.5 7.5

10 mM Tris pH 7.5, 100 mM ammonium sulphate, 10 mM DTT.

Lacey carbon film

ETHANE 100 HOMEMADE PLUNGER

Vitrification instrument: Controlled environment, self-built

Blot for 15 s in controlled environment chamber before plunging FEI/PHILIPS CM200FEG FLOOD BEAM BRIGHT FIELD FIELD EMISSION GUN 200 2 1.6 4.0 50000.0 GATAN LIQUID NITROGEN 95 Astigmatism was corrected at 200,000 times magnification KODAK SO-163 FILM ZEISS SCAI 14 39 8. Eucentric 0 0

ca. 23892 particles were sorted into four groups according to the compositional differences. The reconstruction shows the most complete species and represents ca. 49% of the particle population.

Each particle, phase flipped

C1 OTHER 16.5 FSC 0.5 CUT-OFF SPIDER

Maps were calculated from defocus groups,and added.

11700