title: The Escherichia coli SOS gene dinF protects against oxidative stress and bile salts.
abstract: DNA is constantly damaged by physical and chemical factors, including reactive oxygen species (ROS), such as superoxide radical (O(2)(-)), hydrogen peroxide (H(2)O(2)) and hydroxyl radical (•OH). Specific mechanisms to protect and repair DNA lesions produced by ROS have been developed in living beings. In Escherichia coli the SOS system, an inducible response activated to rescue cells from severe DNA damage, is a network that regulates the expression of more than 40 genes in response to this damage, many of them playing important roles in DNA damage tolerance mechanisms. Although the function of most of these genes has been elucidated, the activity of some others, such as dinF, remains unknown. The DinF deduced polypeptide sequence shows a high homology with membrane proteins of the multidrug and toxic compound extrusion (MATE) family. We describe here that expression of dinF protects against bile salts, probably by decreasing the effects of ROS, which is consistent with the observed decrease in H(2)O(2)-killing and protein carbonylation. These results, together with its ability to decrease the level of intracellular ROS, suggests that DinF can detoxify, either direct or indirectly, oxidizing molecules that can damage DNA and proteins from both the bacterial metabolism and the environment. Although the exact mechanism of DinF activity remains to be identified, we describe for the first time a role for dinF.
authors.affiliation: Centro Nacional de Biotecnología (CSIC), Madrid, Spain.
authors.forename: Jerónimo
authors.initials: J
authors.lastname: Rodríguez-Beltrán
authors.forename: Alexandro
authors.initials: A
authors.lastname: Rodríguez-Rojas
authors.forename: Javier R
authors.initials: JR
authors.lastname: Guelfo
authors.forename: Alejandro
authors.initials: A
authors.lastname: Couce
authors.forename: Jesús
authors.initials: J
authors.lastname: Blázquez
mesh_terms: D000595:Amino Acid Sequence; D017920:Antiporters / Q000235:genetics; D001647:Bile Acids and Salts / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D018384:Oxidative Stress / Q000187:drug effects*; D050050:Protein Carbonylation / Q000187:drug effects; D011755:Pyrophosphatases / Q000502:physiology; D013014:SOS Response, Genetics / Q000235:genetics* / Q000502:physiology; D016415:Sequence Alignment
chemical_list: D017920:Antiporters; D001647:Bile Acids and Salts; C574042:DinF protein, E coli; D029968:Escherichia coli Proteins; C491958:mdtK protein, E coli; D006861:Hydrogen Peroxide; D011755:Pyrophosphatases; C052211:mutT protein, E coli