IrrE peptidase (Deinococcus sp.)
Résumé
Metalloendopeptidase IrrE is required for radiation resistance in Deinococcus bacteria and is involved in gene regulation. After exposure of Deinococcus to radiation or other DNA damage- and oxidative stress-generating conditions, IrrE cleaves and inactivates its substrate, the transcriptional repressor DdrO, thereby inducing the expression of several DNA repair and other genes. DdrO dimerization and DNA binding are abolished after cleavage by IrrE. Crystal structures of IrrE and DdrO have been solved, and data suggest that IrrE is a zinc-dependent enzyme that cleaves the DdrO monomer. Protein pairs related to IrrE and DdrO are present in many bacteria, suggesting that similar stress-induced regulatory mechanisms are widespread.