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The dynamic protein partnership of RNA polymerase in Bacillus subtilis
Author(s) -
Delumeau Olivier,
Lecointe François,
Muntel Jan,
Guillot Alain,
Guédon Eric,
Monnet Véronique,
Hecker Michael,
Becher Dörte,
Polard Patrice,
Noirot Philippe
Publication year - 2011
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.201000790
Subject(s) - bacillus subtilis , rna polymerase , biology , sigma factor , rna , polymerase , transcription (linguistics) , biophysics , microbiology and biotechnology , biochemistry , chemistry , dna , genetics , bacteria , gene , linguistics , philosophy
In prokaryotes, transcription results from the activity of a 400 kDa RNA polymerase (RNAP) protein complex composed of at least five subunits (2α, β, β′, ω). To ensure adequate responses to changing environmental cues, RNAP activity is tightly controlled by means of interacting regulatory proteins. Here, we report the affinity‐purification of the Bacillus subtilis RNAP complexes from cells in different growth states and stress conditions, and the quantitative assessment by mass spectrometry of the dynamic changes in the composition of the RNAP complex. The stoichiometry of RNA polymerase was determined by a comparison of two mass spectrometry‐based quantification methods: a label‐based and a label‐free method. The validated label‐free method was then used to quantify the proteins associated with RNAP. The levels of sigma factors bound to RNAP varied during growth and exposure to stress. Elongation factors, helicases such as HelD and PcrA, and novel unknown proteins were also associated with RNAP complexes. The content in 6S RNAs of purified RNAP complexes increased at the onset of the stationary phase. These quantitative variations in the protein and RNA composition of the RNAP complexes well correlate with the known physiology of B. subtilis cells under different conditions.