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Séminaire


Séminaire invité

Redox regulation of RecA activity

Du 13/09/2018 au 13/09/2018
Benjamin Ezraty (CNRS, IMM)

​Conférencier : Benjamin Ezraty (Aix-Marseille Univ, CNRS, Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée) invité par Laurence Blanchard (BIAM/LBC)

DNA is continuously attacked by reactive oxygen species (ROS) and living cells evolved enzymes that continuously protect DNA such as the protein RecA. In this study, we found that RecA itself is targeted by ROS. We found Met residues of RecA to be targeted by ROS that convert them to methionine sulfoxide (Met-O). In vitro, RecA containing Met-O residues loses its ability to form filaments on DNA, to hydrolyse ATP and to perform DNA strand exchange. Moreover, we show that the methionine sulfoxide reductases MsrA and MsrB, which reduce Met-O residues back to Met are able to repair oxidized RecA. Consistently, we found E. coli msrA msrB mutants to exhibit defects in RecA-dependent process. Two Met residues were identified that are targeted by ROS. Oxidation of one such Met residues leads to loss of function of RecA. In contrast, oxidation of the other Met residue seems to allow constitutive expression of the SOS regulon. We propose that RecA is under redox control and that MsrA/B plays a key role in allowing ROS to act on RecA activity.  


Infos Pratiques

Salle de conférence du bâtiment 177, de 11 h à 12 h, Centre CEA Cadarache
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