title: Rhodopseudomonas palustris CGA010 Proteome Implicates Extracytoplasmic Function Sigma Factor in Stress Response.
abstract: Rhodopseudomonas palustris encodes 16 extracytoplasmic function (ECF) σ factors. 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 σ(RPA4225) (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. Taken together, these data suggest that ECF σ(RPA4225) and the three additional genes make up a sigma factor mimicry system in R. palustris.
authors: §Department of Biological Sciences, University of North Texas, Denton, Texas 76203-5017, United States.|∥Center for Biosafety and Biosecurity Department of Molecular and Medical Genetics, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States.
authors: Michael S
authors: MS
authors: Allen
authors: Gregory B
authors: GB
authors: Hurst
authors: Tse-Yuan S
authors: TY
authors: Lu
authors: §Department of Biological Sciences, University of North Texas, Denton, Texas 76203-5017, United States.
authors: Leslie M
authors: LM
authors: Perry
authors: Chongle
authors: C
authors: Pan
authors: Patricia K
authors: PK
authors: Lankford
authors: Dale A
authors: DA
authors: Pelletier
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001665:Binding Sites; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002853:Chromatography, Liquid; D017124:Conserved Sequence; D004269:DNA, Bacterial / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005964:Glucosyltransferases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D059372:Nucleotide Motifs; D009876:Operon; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D020543:Proteome / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D012241:Rhodopseudomonas / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012808:Sigma Factor / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D013312:Stress, Physiological / Q000235:genetics*; D053719:Tandem Mass Spectrometry; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D020033:Protein Isoforms; D020543:Proteome; D012808:Sigma Factor; D002374:Catalase; D005964:Glucosyltransferases; C099692:trehalose synthase
keywords: ECF σ factor; Rhodopseudomonas palustris; gene regulation; proteomics; stress