title: Dosage-dependent proteome response of Shewanella oneidensis MR-1 to acute chromate challenge.
abstract: Proteome alterations in the metal-reducing bacterium Shewanella oneidensis MR-1 in response to different acute dose challenges (0.3, 0.5, or 1 mM) of the toxic metal chromate [Cr(VI)] were characterized with multidimensional HPLC-MS/MS. Proteome measurements were performed and compared on both quadrupole ion traps as well as linear trapping quadrupole mass spectrometers. We have found that the implementation of multidimensional liquid chromatography on-line with the rapid scanning, high throughput linear trapping quadrupole platform resulted in a dramatic increase in the number of measured peptides and, thus, the number of identified proteins. A total of 2406 functionally diverse, nonredundant proteins were identified in this study, representing a relatively deep proteome coverage for this organism. The core molecular response to chromate challenge under all three concentrations consisted predominantly of proteins with annotated functions in transport and binding (e.g., components of the TonB1 iron transport system, TonB-dependent receptors, and sulfate transporters) as well as a functionally undefined DNA-binding response regulator (SO2426) that might play a role in mediating metal stress responses. In addition, proteins annotated as a cytochrome c, a putative azoreductase, and various proteins involved in general stress protection were up-regulated at the higher Cr(VI) doses (0.5 and 1 mM) only. Proteins down-regulated in response to metal treatment were distributed across diverse functional categories, with energy metabolism proteins dominating. The results presented in this work demonstrate the dynamic dosage response of S. oneidensis to sub-toxic levels of chromate.
authors: Graduate School of Genome Science and Technology, Oak Ridge National Laboratory-University of Tennessee-Knoxville, Tennessee 37830, USA.
authors: Melissa R
authors: MR
authors: Thompson
authors: Nathan C
authors: NC
authors: VerBerkmoes
authors: Karuna
authors: K
authors: Chourey
authors: Manesh
authors: M
authors: Shah
authors: Dorothea K
authors: DK
authors: Thompson
authors: Robert L
authors: RL
authors: Hettich
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002840:Chromates / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D019295:Computational Biology; D004305:Dose-Response Relationship, Drug; D008969:Molecular Sequence Data; D020543:Proteome / Q000032:analysis*; D020592:Shewanella / Q000187:drug effects / Q000378:metabolism; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D001426:Bacterial Proteins; D002840:Chromates; D020543:Proteome