title: Impact of reducing and oxidizing agents on the infectivity of Qβ phage and the overall structure of its capsid.
abstract: Qβ phages infect Escherichia coli in the human gut by recognizing F-pili as receptors. Infection therefore occurs under reducing conditions induced by physiological agents (e.g. glutathione) or the intestinal bacterial flora. After excretion in the environment, phage particles are exposed to oxidizing conditions and sometimes disinfection. If inactivation does not occur, the phage may infect new hosts in the human gut through the oral route. During such a life cycle, we demonstrated that, outside the human gut, cysteines of the major protein capsid of Qβ phage form disulfide bonds. Disinfection with NaClO does not allow overoxidation to occur. Such oxidation induces inactivation rather by irreversible damage to the minor proteins. In the presence of glutathione, most disulfide bonds are reduced, which slightly increases the capacity of the phage to infect E. coli in vitro Such reduction is reversible and barely alters infectivity of the phage. Reduction of all disulfide bonds by dithiothreitol leads to complete capsid destabilization. These data provide new insights into how the phages are impacted by oxidizing-reducing conditions outside their host cell and raises the possibility of the intervention of the redox during life cycle of the phage.
authors.affiliation: LCPME (Laboratory of Physical Chemistry and Microbiology for the Environment), Joint Research Unit - UMR 7564, CNRS/Université de Lorraine, Nancy 54000, France CNRS, LCPME, UMR 7564, Institut Jean Barriol (IJB), Nancy 54000, France Food Safety Department, ACTALIA, Saint Lô 50000, France.
authors.forename: Pauline
authors.initials: P
authors.lastname: Loison
authors.affiliation: ACTIA, 16 rue Claude Bernard, 75231 Paris Cedex 05, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Majou
authors.affiliation: Université de Lorraine, Tree-Microbe Interactions Department, UMR1136, F-54500 Vandœuvre-lès-Nancy, France INRA, Tree-Microbe Interactions Department, UMR1136, F-54280 Champenoux, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Gelhaye
authors.affiliation: Food Safety Department, ACTALIA, Saint Lô 50000, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Boudaud
authors.affiliation: LCPME (Laboratory of Physical Chemistry and Microbiology for the Environment), Joint Research Unit - UMR 7564, CNRS/Université de Lorraine, Nancy 54000, France CNRS, LCPME, UMR 7564, Institut Jean Barriol (IJB), Nancy 54000, France christophe.gantzer@univ-lorraine.fr.
authors.forename: Christophe
authors.initials: C
authors.lastname: Gantzer
mesh_terms: D001435:Bacteriophages / Q000254:growth & development*; D002213:Capsid / Q000502:physiology; D036022:Capsid Proteins / Q000378:metabolism*; D002352:Carrier Proteins; D004229:Dithiothreitol / Q000737:chemistry; D004926:Escherichia coli / Q000821:virology*; D000069196:Gastrointestinal Microbiome; D041981:Gastrointestinal Tract / Q000382:microbiology* / Q000821:virology*; D005978:Glutathione / Q000737:chemistry; D006801:Humans; D008018:Life Cycle Stages; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D036022:Capsid Proteins; D002352:Carrier Proteins; D016877:Oxidants; D005978:Glutathione; D004229:Dithiothreitol
keywords: Qβ phage; capsid proteins; disulfide bonds; inactivation; oxidation; reduction