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Title: Rhodopseudomonas palustris CGA010 Proteome Implicates Extracytoplasmic Function Sigma Factor in Stress Response

Rhodopseudomonas palustris encodes 16 extracytoplasmic function (ECF) σ factors. In this paper, to begin to investigate the regulatory network of one of these ECF σ factors, the whole proteome of R. palustris CGA010 was quantitatively analyzed by tandem mass spectrometry from cultures episomally expressing the ECF σRPA4225 (ecfT) versus a WT control. Among the proteins with the greatest increase in abundance were catalase KatE, trehalose synthase, a DPS-like protein, and several regulatory proteins. Alignment of the cognate promoter regions driving expression of several upregulated proteins suggested a conserved binding motif in the -35 and -10 regions with the consensus sequence GGAAC-18N-TT. Additionally, the putative anti-σ factor RPA4224, whose gene is contained in the same predicted operon as RPA4225, was identified as interacting directly with the predicted response regulator RPA4223 by mass spectrometry of affinity-isolated protein complexes. Furthermore, another gene (RPA4226) coding for a protein that contains a cytoplasmic histidine kinase domain is located immediately upstream of RPA4225. The genomic organization of orthologs for these four genes is conserved in several other strains of R. palustris as well as in closely related α-Proteobacteria. Finally, taken together, these data suggest that ECF σRPA4225 and the three additional genes make up a sigmamore » factor mimicry system in R. palustris.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [3] ;  [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division; Univ. of North Texas, Denton, TX (United States). Dept. of Biological Sciences; Univ. of North Texas Health Science Center, Fort Worth, TX (United States). Center for Biosafety and Biosecurity. Dept. of Molecular and Medical Genetics
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division
  4. Univ. of North Texas, Denton, TX (United States). Dept. of Biological Sciences
Publication Date:
OSTI Identifier:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Journal of Proteome Research
Additional Journal Information:
Journal Volume: 14; Journal Issue: 5; Journal ID: ISSN 1535-3893
American Chemical Society (ACS)
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Contributing Orgs:
Univ. of North Texas, Denton, TX (United States)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES ECF σ factor; gene regulation; proteomics; Rhodopseudomonas palustris; stress