fa بیوشیمی Biochemistry <p style="text-align: justify;"><em><strong>Background: </strong></em>Sigma factors are proteins that regulate transcription in bacteria. Sigma factors can be activated in response to different environmental conditions. The rpoS (RNA polymerase, sigma S) gene encodes sigma-38 (&sigma;38, or RpoS), a 37.8 kDa protein in <em>Pseudomonas aeruginosa (P. aeruginosa)</em> strains. RpoS is a central regulator of the general stress response and operates in both retroactive and proactive manners; not only does it allow the cell to survive environmental challenges; it also prepares the cell for subsequent stresses (cross-protection).</p> <p style="text-align: justify;"><em><strong>Methods: </strong></em>The significance of RpoS for stress resistance and protein expression in stationary-phase <em>P. aeruginosa</em> cells was assessed. The goal of the current study was to characterize RpoS of <em>P. aeruginosa</em> PAO1 using bioinformatics tools.</p> <p style="text-align: justify;"><em><strong>Results: </strong></em>The results showed that RpoS is an unstable protein that belongs to the sigma-70 factor family. Secondary structure analysis predicted that random coil is the predominant structure followed by extended alpha helix. The three-dimensional (3D) structure was modeled using SWISS-MODEL Workspace.</p> <p style="text-align: justify;"><em><strong>Conclusion:</strong></em> Determination of sequence, function, structure, and predicted epitopes of RpoS is important for modeling of inhibitors that will help in the design of new drugs to combat multi-drug-resistant (MDR) strains. Such information may aid in the development of new diagnostic tools, drugs, and vaccines for treatment in endemic regions.</p> Bioinformatics, In silico, Pseudomonas aeruginosa, RpoS, Therapy 32 42 http://rbmb.net/browse.php?a_code=A-10-1-48&slc_lang=fa&sid=1 Mansour Sedighi 10031947532846006097 10031947532846006097 No Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Mohsen Moghoofei 10031947532846006098 10031947532846006098 No Department of Virology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Ebrahim Kouhsari 10031947532846006099 10031947532846006099 No Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Abazar Pournajaf 10031947532846006100 10031947532846006100 No Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Behzad Emadi 10031947532846006101 10031947532846006101 No Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran Masoud Tohidfar 10031947532846006102 10031947532846006102 No Agricultural Biotechnology Research Institute of Iran, Tehran, Iran Mehrdad x Gholami mehrdad_gholami90@yahoo.com 10031947532846006103 10031947532846006103 Yes Department of Microbiology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran