Proteomic Profiling of Deinococcus radiodurans Reveals Irradiation-Induced Proteins and Their Associated Functional Pathways

Deinococcus radiodurans is an extremophilic microorganism renowned for its extraordinary resistance to ionizing radiation. Its unique DNA repair capacity and robust protein protection mechanisms make it an important model organism for studying cellular responses to radiation stress. Although multiple radiation-resistance mechanisms have been elucidated, proteomic-level insights - particularly regarding proteins specifically expressed after irradiation - remain limited. In this study, we employed high-resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with bioinformatic analysis to systematically investigate the proteomic profiles of D. radiodurans at 0, 1, and 3 hours following exposure to 6 kGy of γ-radiation. Unlike traditional differential expression analysis, this study focused on proteins exclusively identified in the irradiated group, from which a total of 62 irradiation-induced proteins were identified. Gene Ontology (GO) enrichment analysis revealed that these proteins are predominantly involved in essential biological processes such as DNA repair, DNA binding, and cellular response to gamma radiation. Further analysis showed that irradiation-induced DNA repair proteins - RuvC, DdrA, and DdrB - exhibited a time-dependent increase in peptide-spectrum match (PSM) counts between 0 and 3 hours post-irradiation, indicating their critical roles in responding to radiation-induced genomic damage. These findings provide new proteomic evidence for understanding microbial radioresistance and offer promising molecular targets for applications in space biology and radiation protection technologies.