Involvement of PG1037 in the repair of 8‐oxo‐7,8‐dihydroguanine caused by oxidative stress in Porphyromonas gingivalis

Abstract

BackgroundThe PG1037 gene is part of the uvrA‐PG1037‐pcrA operon in Porphyromonas gingivalis. It encodes for a protein of unknown function upregulated under hydrogen peroxide (H2O2)‐induced oxidative stress. Bioinformatic analysis shows that PG1037 has a zinc‐finger motif, two peroxidase motifs, and one cytidylate kinase domain. The aim of this study is to characterize further the role of the PG1037 recombinant protein in the unique 8‐oxoG repair system in P. gingivalis.Materials and MethodsPG1037 recombinant proteins with deletions in the zinc‐finger or peroxidase motifs were created. Electrophoretic mobility shift assays were used to evaluate the ability of the recombinant proteins to bind 8‐oxoG‐containing oligonucleotides. Zinc binding, peroxidase, and Fenton reaction assays were used to assess the functional roles of the rPG1037 protein. A bacterial adenylate cyclase two‐bride assay was used to identify the partner protein of PG1037 in the repair of 8‐oxoG.ResultsThe recombinant PG1037 (rPG1037) protein carrying an N‐terminal His‐tag demonstrated an ability to recognize and bind 8‐oxoG‐containing oligonucleotide. In contrast to the wild‐type rPG1037 protein, the zinc‐finger motif deletion resulted in the loss of zinc and 8‐oxoG binding activities. A deletion of the peroxidase motif‐1 showed a decrease in peroxidase activity. Using a bacterial adenylate cyclase two‐hybrid system, there was no observed protein‐protein interaction of PG1037 with UvrA (PG1036), PcrA (PG1038), or mismatch repair system proteins.ConclusionsTaken together, the results show that PG1037 is an important member of a novel mechanism that recognizes and repairs oxidative stress‐induced DNA damage in P. gingivalis.