title: Protective role of tolC in efflux of the electron shuttle anthraquinone-2,6-disulfonate.
abstract: Extracellular electron transfer can play an important role in microbial respiration on insoluble minerals. The humic acid analog anthraquinone-2,6-disulfonate (AQDS) is commonly used as an electron shuttle during studies of extracellular electron transfer. Here we provide genetic evidence that AQDS enters Shewanella oneidensis strain MR-1 and causes cell death if it accumulates past a critical concentration. A tolC homolog protects the cell from toxicity by mediating the efflux of AQDS. Electron transfer to AQDS appears to be independent of the tolC pathway, however, and requires the outer membrane protein encoded by mtrB. We suggest that there may be structural and functional relationships between quinone-containing electron shuttles and antibiotics.
authors.affiliation: Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: J Bruce H
authors.initials: JB
authors.lastname: Shyu
authors.forename: Douglas P
authors.initials: DP
authors.lastname: Lies
authors.forename: Dianne K
authors.initials: DK
authors.lastname: Newman
mesh_terms: D000880:Anthraquinones / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004579:Electron Transport; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D009154:Mutation; D020592:Shewanella / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000880:Anthraquinones; D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; C116147:MtrB protein, Shewanella putrefaciens; C408124:anthraquinone-2,6-disulfonate; C073126:tolC protein, E coli